The Musculoskeletal System - Jones & Bartlett Learning

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The Musculoskeletal System © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

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Learning Objectives 1. Describe muscle structure in terms ofLearning, muscle cells, tendons, © Jones & Bartlett LLCand bones. (p 76–82) NOT FOR SALE OR DISTRIBUTION 2. Describe the neuromuscular junction and explain the function(s) for each part. (p 77–78) 3. Describe the structure of a sarcomere. (p 77) 4. Describe the sliding filament theory of muscle contraction. (p 78–80) 5. Bartlett Explain polarization, depolarization, and repolarization in terms of & Learning, LLC ions and charges. (p 79–80)

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6. Name the© energy sources& forBartlett muscle contraction. (p 80–81) LLC Jones Learning, 7. Explain the importance of hemoglobin, myoglobin, oxygen debt, and NOT FOR SALE OR DISTRIBUTION lactic acid. (p 81) 8. Describe the difference between antagonistic and synergistic muscles. (p 82) 9. State the major muscles of the body and their functions. (p 83–92)

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Skidplate: © Photodisc; Cells © ImageSource/age fotostock

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6

Fascia surrounds every muscle and may form cordlike tendons The human body is a well-designed system whose form, beyond each muscle’s end. Tendon fibers may intertwine with upright posture, and movement are provided by the musculobone fibers to attach muscles to bones. Broad sheets of fibers skeletal system. The term musculoskeletal refers to the bones that may attach to bones or to coverings of other muscles & Bartlett Learning, LLC © the Jones & Bartlett Learning, LLC and voluntary muscles of © theJones body. The musculoskeletal sysare known as aponeuroses. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION tem also protects the vital internal organs of the body. Muscle Skeletal muscles are closely surrounded by a layer of is composed of fibers that contract, causing movement. The connective tissue known as an epimysium. The muscle is body contains three types of muscle: skeletal muscle (striated), separated into small compartments by another layer known smooth muscle, and cardiac muscle. Muscles are a form of tisas the perimysium. Inside these compartments are muscle sue that causes body movement. The understanding of muscle fascicles (muscle fasciculus ), which Learning, are bundles of skeletal © Jones & Bartlett Learning, LLC © Jones & Bartlett LLC tissue is very important to your clinical field practice. Whether muscle cells bound together by connective tissue and formNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the patient is an injured athlete, a victim of a motor vehicle ing one of the constituent elements of a muscle fibers. These crash, or has runaway tachycardia caused by irritable cardiac layers form a thin covering (endomysium). The many layers muscle tissue, you need to be familiar with how muscles work. of connective tissue that enclose and separate skeletal muscles allow a great deal of independent movement.

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Pathophysiology

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Skeletal muscle, so named because it attaches to the bones of the skeleton, forms the major muscle mass of the body. It Tendon lacerations, especially in the hand, may result in is also called voluntary muscle because skeletal muscle can long-term impairment unless they are properly treated. be consciously controlled by the brain Figure 4-1 . The body Unless a tendon is completely transected, the patient © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC contains more than 350 skeletal muscles. often will retain some motion of the finger. The examiner NOT FORtoSALE DISTRIBUTION NOT SALE OR DISTRIBUTION must test for pain against resistance motionOR rather Movement of the body, likeFOR waving or walking, results than simply motion itself. A partially torn or lacerated from skeletal muscle contraction or relaxation. Usually a tendon will allow motion but also causes pain against specific motion is the result of several muscles contracting resistance to motion. If a partially torn tendon is missed and relaxing simultaneously. Individual skeletal muscles are and the hand is improperly immobilized, the tear may separated from other muscles and held in position by layers become© complete. repair is delayed in such a situation, © Jones & Bartlett Learning, LLC JonesIf & Bartlett Learning, LLC of fibrous connective tissue known as fascia. the surgical procedure becomes much more complicated

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Fascia

and the NOT resultsFOR are notSALE as good.OR

DISTRIBUTION

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© Jones & Bartlett Learning, LLC Epimysium NOT FOR SALE OR DISTRIBUTION Perimysium

The median nerve passes through a strong band of connective tissue in the wrist, the carpal tunnel. Many conditions, including glandular diseases, pregnancy, and overuse, can result in irritation and compression of the nerve, or carpal tunnel syndrome. Carpal tunnel © Jones & Bartlett Learning, LLCsyndrome is a common source © Jones & Bartlett Learning, LLC of occupational disability NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION claims.

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Muscle fibers

Sarcolemma

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Structure of Skeletal Muscle Fibers © Jones & Bartlett Learning, LLC A single cell thatFOR contracts in response to stimulation and NOT SALE OR DISTRIBUTION relaxes when the stimulation ceases is known as a skeletal muscle fiber. These fibers are thin, elongated cylinders with rounded ends. The cell membrane (sarcolemma) lies above the cytoplasm (also known as sarcoplasm), with many small, © Jones & Bartlett Learning, oval-shaped mitochondria and LLC nuclei. The sarcoplasm is NOT made FORup SALE ORthreadlike DISTRIBUTION of many myofibrils arranged parallel to each other.

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Myofi brils have thick protein fi laments composed of extending inward and passing through the fiber. NOT channels FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

myosin, and thin protein filaments mostly composed of actin These tubules open to the outside of the muscle fiber Figure 4-2 . These filaments are organized so that they appear and contain extracellular fluid. Each tubule lies between as striations—areas of alternating colored bands of skeletal enlarged structures called cisternae, near the point where muscle fiber. The repeating patterns of striation units that actin and myosin filaments overlap. Together, the sarcoplasJones & Bartlett Learning, LLC © Jones Bartlett Learning, LLC appear along each muscle©fiber are referred to as sarcomeres . mic reticulum and T-tubules activate & muscle contraction Muscles are basically considered to beSALE collections sarcowhen stimulated. NOT FOR SALE OR DISTRIBUTION NOT FOR ORofDISTRIBUTION meres. Neurologic Structures There are two main parts of the striation pattern of skelNeurons (nerve cells) conduct nerve impulses. Motor etal muscle fibers. The light bands (I bands) are made up of neurons control effectors, which include skeletal muscle. thin filaments of actin attached to Z lines. The dark bands ©are Jones & of Bartlett Learning, LLC © muscle Jonesfiber & Bartlett Learning, LLCmanEach skeletal is connected in a functional (A bands) made up thick filaments of myosin that overner to the axon a motor neuron. These pass outward from lap thin NOT filaments of actin. There a central region (H zone) FOR SALE ORis DISTRIBUTION NOTofFOR SALE OR DISTRIBUTION the brain or spinal cord. Each functional connection is called of thick filaments, with a thickened area (the M line) that a synapse. At the synapses, neurons communicate with other consists of proteins holding them in place. Sarcomeres extend cells by releasing neurotransmitters (chemicals that enable from one Z line to another Z line, as shown in Figure 4-2. communication). Skeletal muscle fibers usually contract Inside the sarcoplasm of a muscle fiber, a network © Jones Bartlett Learning, BartlettbyLearning, LLC when& stimulated motor neurons. of & channels surrounds each LLC myofibril Figure 4-3 . These© Jones NOT FOR SALE OR DISTRIBUTION FOR SALE OR DISTRIBUTION membranous channels form the sarcoplasmic reticulumNOT . A neuromuscular junction is the connection between Transverse tubules (T-tubules) are other membranous a motor neuron and a muscle fiber Figure 4-4 . A motor

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Your unit is standing by at the local high school’s regional soccer tournament. Four games have been playing simultaneously for the past 4 hours and there are 2 more hours to go. Suddenly, you notice a commotion over on field 4 and find a girl has been injured and is lying on the field. Witnesses say that she was running after the ball and came to a © Jones & Bartlett LLC © Jones Bartlett Learning, LLC sudden stop while attemptingLearning, to make a turn. You determine that the scene is safe,& and your general impression of this patient reveals girl whose right knee is flexed and swollen. The patientNOT did not strike her head lose consciousness. NOT FORa SALE OR DISTRIBUTION FOR SALE ORorDISTRIBUTION She is crying in apparent pain and is attempting to hold her knee still. You take standard precautions and determine that there are no immediate life-threats. Examination reveals that the patient has no injuries to the spine, head, or body parts other than the knee. The patient states that she heard a pop and now feels that the knee joint is unstable and she cannot bear any weight on the leg.

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Recording Time: 0 Minutes

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1. What type of muscle is involved in the function of a joint such as the knee?

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 2. What is the primary function of the type of muscle found around the knee? NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

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A Band Bundles of muscle fibers

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I Band

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Muscle fiber (a single cell)

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line M line Z line LLC © Jones & ZBartlett Learning, Thick Thin NOT FOR SALE OR DISTRIBUTION filament filament (Actin)

Skeletal muscle

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(Myosin)

(contracting sarcomere)

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Bone A band

I band © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

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© Jones & plate Bartlett Learning, LLC muscle fiber mem-© Jones & Bartlett Learning, LLC end  is formed by specialized Motor Units NOT FOR SALE OR DISTRIBUTION branes. Motor end plates have abundant mitochondria andNOT FOR SALE OR DISTRIBUTION

Most muscle fibers have a single motor end plate, though nuclei, with greatly folded sarcolemmas. motor neuron axons have many branches connecting the Motor neurons branch out and project into muscle fiber motor neuron to various muscle fibers. When an impulse membrane recesses. Cytoplasm at these distal ends have is transmitted, all of the connected muscle fibers contract at many mitochondria and tiny synaptic vesicles that con© Jones & Bartlett Learning, LLC Jones & Bartlett LLC the same time. A motor unit© is therefore made up of a Learning, motor tain neurotransmitters. On receiving impulses, the vesicles NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION neuron and the muscle fibers that it controls Figure 4-5 . release neurotransmitters into the synaptic cleft between the neuron and motor end plate, stimulating muscle contraction.

Contraction of Skeletal Muscles

Pathophysiology

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Certain types of nerve gas, as well as ingredients in certain pesticides, bind to acetylcholinesterase and inhibit its function. Thus, acetylcholine is not degraded in the synaptic cleft and continues to constantly stimulate the muscle fiber, resulting in spastic paralysis, a condition in Bartlett which muscles fire spontaneously © Jones & Learning, LLC but cannot relax, resulting in paralysis, an inability to respond to volunNOT FORtary SALE OR DISTRIBUTION stimuli.

Skeletal muscles contract when organelles and molecules bind myosin to actin & to Bartlett cause a pulling action. LLC The myo© Jones Learning, fibrils thenNOT moveFOR as theSALE actin and filaments slide, ORmyosin DISTRIBUTION shortening the muscle fiber and pulling on its attachments.

Required Chemicals Myosin molecules are made up of two protein strands with globe-shaped cross-bridges that project © Jones & Bartlett Learning, LLC outward. Groups of many myosin molecules make up a myosin (thick) filament. NOT FOR SALE OR DISTRIBUTION Actin molecules are globe-shaped with a binding site that attaches to myosin cross-bridges. Groups of many

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© Jones & Bartlett Learning, LLC actin molecules twist in double NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC NOT FOR SALEMuscle OR DISTRIBUTION Tendon

strands (helixes) to form an actin (thin) filament, which includes the proteins known as troponin and tropomyosin Figure 4-6 . © Jones & Bartlett Learning, LLC ©Strands Jonesof&tropomyosin Bartlett Learning, LLC preMuscle fiber ventNOT actin–myosin (aNOT single FOR SALE OR DISTRIBUTION FOR SALEinteraction. OR DISTRIBUTION muscle cell) One subunit of the troponin molecule binds to tropomyosin, forming the troponin–tropomyosin Cell membrane complex. Another subunit binds (sarcolemma) T-tubule © Jones & Bartlett Learning, LLC © Jones &toBartlett G actin Learning, to hold the LLC complex position. A third subunit has NOT FOR SALE OR DISTRIBUTION NOT FOR in SALE OR DISTRIBUTION a receptor binding a calcium ion. When the muscle is at rest, intracellular calcium is very low, and the Sarcoplasmic reticulum binding site is empty. Contractions © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC unless the position cannot occur NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION of the troponin–tropomyosin complex changes to expose the active sites on F actin. The position change occurs when calcium ions Nucleus Mitochondrion Myofibril bind to receptors on the troponin © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC molecules. This binding causes a NOT SALEofOR NOT FOR SALE OR DISTRIBUTION change in FOR the structure the DISTRIBUTION actin molecule that allows actin and Muscle myosin to react with each other, fibers forming a troponin-tropomyosin complex, resulting in Motor neuron muscle contraction. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The functional unit of skeletal muscle is the sarcomere. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION When sarcomeres shorten within a skeletal muscle fiber, a skeletal muscle contracts. This occurs because of the crossbridges pulling on the thin filaments of actin. The sliding Voltage-gated Synaptic end bulb Motor end plate Ca++ channel filament model is so named because of the way sarcomeres shorten, with thick and thin filaments sliding past each other Axon © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC toward the center of the sarcomere, from both ends. NOT FOR SALE OR DISTRIBUTION Neurotransmitter NOT FOR SALE OR DISTRIBUTION Myosin filaments contain the enzyme adenosine triphosphatase (ATPase) in their globe-shaped portions. This enzyme Neurotransmitter catalyzes the breakdown of adenosine triphosphate (ATP) to receptors both adenosine diphosphate (ADP) and phosphate, releasing Action potential energy. The myosin cross-bridges assume a “cocked”Learning, posi© Jones & Bartlett Learning, LLC © Jones & Bartlett LLC tion, binding to actin to pull on the thin filament. After the Synaptic NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION vesicles pulling occurs, the cross-bridge is released from actin before the ATP splits. The cycle repeats as long as there is enough ATP for energy and muscular stimulation occurs. Synaptic cleft

© Jones & Bartlett Learning, LLC T-tubule NOT FOR SALE OR DISTRIBUTION Ca++

Sarcolemma

Sarcoplasmic

reticulum © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

Contraction Stimulus © Jones & Bartlett Learning, LLC The impulse that causes contraction of skeletal muscle is NOT FOR SALE OR DISTRIBUTION transmitted through motor neurons as a nerve impulse. These impulses are also known as action potentials, and are transmitted from one cell to another in the nervous system, causing each successive cell in the chain to “fire.” The process by which cells activate in response to the action potential is © Jones & Bartlett Learning, LLC known as depolarization . When the cell is at rest, ions are NOT FOR SALE OR DISTRIBUTION actively transported into and out of the cell to create an electrochemical gradient across the cell membrane. This is known

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Motor units Axon terminals

Muscle fibers

Myosin

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Actin

Resting

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Ca++ Ca++

ADP P

ADP P

Tropomyosin Troponin

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© Jones & Bartlett Learning, LLC ADP P NOT FOR SALE OR DISTRIBUTION ADP P

(b)

© Jones & Bartlett Learning, LLC © Jones Learning, LLC Step&1:Bartlett Action potential as being polarized. When the cell is activated by the release NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

of a neurotransmitter, proteins in the cell wall open rapidly, allowing a rapid influx of ions that equalizes the charges on ADP P Ca++ either side of the cell wall. When the charges are equal, the cell has depolarized, and the protein channels close. Then the process of repolarization begins, which again creates the © Jones & Bartlett Learning, LLC Ca++ © Jones & Bartlett Learning, LLC ADP P electrochemical gradient so the cell can “fi re” again. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The neurotransmitter that stimulates skeletal muscle to (c) Catch Myosin binding site contract is acetylcholine. Synthesized in the cytoplasm of Step 2: Myosin-actin binding motor neurons, acetylcholine is released into the synaptic clefts between motor neuron axons and motor end plates. It rapidly © diffuses, binding to certain protein receptors Jones & Bartlett Learning, LLC in the © Jones & Bartlett Learning, LLC muscle fi ber membrane, increasing permeability to sodium. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ADP P These charged particles stimulate a muscle impulse that passes in many directions over the muscle fiber membrane. ADP P This impulse eventually reaches the sarcoplasmic reticulum. (d) Drive The sarcoplasmic reticulum has a high calcium ion concentration, and itLearning, responds to the muscle impulse by becom-© Jones © Jones & Bartlett LLC &3:Bartlett Learning, LLC Step Power stroke ing more permeable to calcium. Calcium is then releasedNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION into the cytoplasm where it binds to troponin, initiating a contraction cycle in which troponin and tropomyosin interATP act to form linkages between actin and myosin filaments. The muscular contraction also requires ATP and continues ATP Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC as long as acetylcholine is©released. (e) Release Muscle relaxation is caused the decomposition of aceNOT FOR SALE OR DISTRIBUTION NOT by FOR SALE OR DISTRIBUTION Step 4: ATP binding and actin-myosin release tylcholine via the enzyme acetylcholinesterase. It prevents a single nerve impulse from stimulating the muscle fiber continuously. When the stimulus ceases, calcium ions are transADP P ported back to the sarcoplasmic reticulum. The actin and Jones & Bartlett Learning, © Jones & Bartlett Learning, LLC myosin © linkages break, and the muscle relaxes.LLC

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ADP P Energy Sources (f) Recover Muscle contraction, regardless of type, requires energy. Step 5: ATP cleavage Muscle fibers have just enough ATP for short-term contraction. ATP must be regenerated when fibers are active, using © Jones & Bartlett Learning, existing ATP molecules in the LLC cells. ATP is regenerated from© Jones & Bartlett Learning, LLC NOT FOR OR DISTRIBUTION ADPSALE and phosphate. Creatine phosphate enables this withNOT FOR SALE OR DISTRIBUTION high-energy phosphate bonds. It is between four and six

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC times more abundant in muscle fi bers than ATP; however, it muscle OR becomes fatigued and cramps, it experiences NOT When FOR aSALE DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

does not directly supply energy. It stores excess energy from a sustained, involuntary contraction. Though not fully the mitochondria in the phosphate bonds. understood, muscle cramps appear to be caused by changes When ATP breaks down, energy from creatine phosphate in the extracellular fluid surrounding muscle fibers and is transferred to ADP molecules to convert them back into motor neurons. Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ATP. Creatine phosphate © stores are exhausted rapidly when Production of Heat muscles are active; therefore, muscles use cellular respiNOT FOR SALE OR DISTRIBUTION NOTtheFOR SALE OR DISTRIBUTION Most of the energy released in cellular respiration becomes ration of glucose as energy to synthesize ATP. heat. Muscle tissue generates a large amount of heat because muscles form so much of the total body mass. Body temperature is partially maintained by the blood transporting Clinical Tip heat generated by the muscle to other body tissues. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC

FOR ORtheDISTRIBUTION ManyNOT cardiac drugsSALE influence passage of calcium, sodium, or both across cell membranes. These drugs include standard anti-dysrhythmic agents, such as lidocaine or procainamide, and calcium channel blockers, such as verapamil, diltiazem, and amiodarone.

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Muscle Responses Muscle contractions can be observed by using a myogram to “see” muscle twitches. This requires electrical signals that can cause various strengths and frequencies of responses. A muscle fiber will remainLearning, unresponsiveLLC until a certain strength of © Jones & Bartlett Learning, LLC © Jones & Bartlett stimulation (the threshold stimulus) is applied. An action NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION potential is then generated that results in an impulse that Oxygen Use and Debt spreads throughout the fiber, releasing calcium and activatOxygen is required for the breakdown of glucose in the mitoing cross-bridge binding. This causes contraction. chondria. Red blood cells carry oxygen, bound to hemogloThe contractile response of a fiber to an impulse is called bin molecules. Hemoglobin is the pigment that makes blood © Jones & Bartlett Learning, LLC Jones & Bartlettfollowed Learning, LLC a twitch, and it consists of a©period of contraction appear red. The pigmentNOT myoglobin is synthesized in the by a period of relaxation. A NOT myogram records this OR pattern of FOR SALE DISTRIBUTION FOR SALE OR DISTRIBUTION muscles to give skeletal muscles their reddish-brown color. events. There is a brief delay between the stimulation time Myoglobin can also combine with oxygen and temporarily and the beginning of contraction. This is known as the latent store it in order to reduce muscular requirements for continperiod, and may last less than 2 milliseconds. A myogram uous blood supply during contraction. results from the combined twitches of muscle fibers taking When skeletal muscles are used for a moreLLC than a min© Jones & Bartlett Learning, © JonesThere & Bartlett LLC the part in contraction. are twoLearning, types of twitches: ute or two, anaerobic respiration is required for energy. In NOT FOR SALE OR DISTRIBUTION NOTslow FOR SALE DISTRIBUTION fatigue-resistant twitch and OR the fatigable fast twitch. one type of anaerobic respiration, glucose is broken down The force of individual twitches combines via the provia glycolysis to yield pyruvic acid, which is converted to cess of summation. When sustained contractions have no lactic acid. Lactic acid can accumulate in muscles, but often relaxation at all, they are referred to as either tetanic condiffuses in the bloodstream, reaching the liver, where it is tractions or the condition known as tetany. High intensities converted back into glucose. LLC © Jones & Bartlett Learning, © Jones & Bartlett Learning, of stimulation can activate many LLC motor units (recruitment). is exercising strenuously, oxygen is usedNOT FOR SALE OR DISTRIBUTION NOT FOR When SALEa person OR DISTRIBUTION Actions of Skeletal Muscles mostly to synthesize ATP. As lactic acid increases, an oxygen Skeletal muscles cause unique movements based on the type debt develops. Oxygen debt is equivalent to the amount of of joint they attach to and where the attachment points are. oxygen that liver cells require to convert the lactic acid into When a muscle appears to be at rest, its fibers still undergo glucose, as well as the amount needed by muscle cells to © Joneslevels. & Bartlett Learning, LLC Jones & Bartlett LLC some sustained contraction, © known as muscle tone or Learning, tonus. restore ATP and creatine phosphate It may take several hours the body to convert lactic NOT FOR SALE OR DISTRIBUTION NOTforFOR SALE OR DISTRIBUTION Origins and Insertions acid back into glucose. Muscles may experience a change in One end of a skeletal muscle usually is fastened to a relatheir metabolic activity as exercise levels change. Increased tively immovable part (origin) at a moveable joint. The other exercise raises the muscles’ capacity for glycolysis. Aerobic end connects to a one side of a movable joint (insertion) on exercise increases the muscles’ capacity for aerobic respiration. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, the other side of the joint. As contraction occurs,LLC the insertion is pulled toward origin.OR There may be more than MuscleNOT Fatigue FOR SALE OR DISTRIBUTION NOT FORthe SALE DISTRIBUTION one origin or insertion, such as in the biceps brachii muscle Prolonged exercise may cause a muscle to become unable of the arm. When this muscle contracts, the insertion being to contract. This condition is called fatigue, and it may also pulled toward its origin causes the forearm to flex and supioccur because of interruption of muscular blood supply, nate at the elbow Figure 4-7 . or occasionally a lack of acetylcholine in the motor neuron © Jones & Bartlett Learning, LLC & Bartlett Learning, LLC head of a muscle is the part closest to its origin. The axons. Lactic acid accumulation is the usual cause of mus-© JonesThe NOT FOR DISTRIBUTION FORflexion SALE OR DISTRIBUTION describes a decrease in the angle of a joint; for cularSALE fatigue.OR As lactic acid lowers pH levels, muscle fibersNOT term example, a movement of the forearm that causes it to bend become progressively less able to respond to stimulation. © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION.

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© Jones & Bartlett Learning, LLC skeletalOR muscle cells. The myofilaments of smooth NOT than FORdoSALE DISTRIBUTION

muscle are not organized into sarcomeres; therefore, smooth muscle is considered to be nonstriated muscle. The two types of smooth muscle are visceral and mulOrigin tiunit smooth muscle. Visceral smooth muscle is the more © Jones & Bartlett Learning, LLC © normally Jones & Bartlett LLC Tendon common of the two types and is made up ofLearning, sheets of muscle that form the layers of the digestive, reproductive, NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION and urinary tracts. Electrochemical signals travel quickly from one cell to another because numerous conduction Muscle body areas, or gap junctions, interconnect the individual cells. Multiple sheets of smooth muscle tend to function as a single © Jones & Bartlett Learning, LLC © Jones Bartlett Learning, Epimysium unit because of rapid & transmission of the action LLC potential. Sometimes,NOT contraction muscles in this fashion is referred NOT FOR SALE OR DISTRIBUTION FOR of SALE OR DISTRIBUTION to as a functional syncytium. Multiunit smooth muscle may be found in sheets (as in Stationary Insertion the walls of blood vessels), in small bundles (as in the iris of bone the eye), or as single cells (as in the capsule of the spleen). © Jones & Bartlett Learning, LLC & Bartlett Learning, LLC Endostium © Jones This form of smooth muscle has few gap junctions; each cell NOT FOR SALE OR DISTRIBUTION NOT contracts FOR SALE OR DISTRIBUTION as an independent unit when stimulated by nerves. Thus, the rate of contraction is somewhat slower than that of visceral smooth muscle. The autonomic nervous system innervates smooth musArticulation Moving bones cle. Because the autonomic nervous system is not under © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC conscious control, smooth muscle contraction is involunFOR SALE NOT FOR SALE OR DISTRIBUTION tary. Unlike skeletal muscle,NOT smooth muscle has OR very DISTRIBUTION little sarcoplasmic reticulum. The calcium required for contraction diffuses into the cell from the surrounding fluid (extracellular fluid). Calcium binds to an intracellular protein, calmodulin©, resulting muscle contraction. © Jones & Bartlett Learning, LLC Jones &in Bartlett Learning,Whether LLC or not actin and myosin fi laments actually form cross-bridges at the elbow. termSALE extension an increase in the NOTThe FOR ORdescribes DISTRIBUTION NOT FOR SALE OR DISTRIBUTION between each other is unknown. In general, contraction of angle of a joint; for example, a movement of the forearm that smooth muscle occurs at a slower rate than that of skeletal straightens the elbow. muscle. In addition to electrochemical stimulation that the autoSkeletal Muscle Interactions nomic nervous system provides to smooth muscle, various Skeletal muscles usually function in groups, with the ner© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC hormones released by the glands also affect smooth muscle vous system stimulating the desired muscles to perform the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE DISTRIBUTION contraction. ForOR example, the hormone oxytocin stimulates intended function. A muscle that contracts to provide most contractions of uterine smooth muscle. of a desired movement is called a prime mover or agonist. Other muscles, known as synergists, work with a prime mover to make its action more effective. For example, when Cardiac Muscle you bend your forearm, the agonist muscles are the biceps, © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC whereas the synergists are the brachialis. NOT FORmuscle, SALEand ORmuscle DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Cardiac muscle is striated like skeletal Other muscles act as antagonists to prime movers. They cells contain only one nucleus. Intercalated disks are branchcause movement in the opposite direction. In the above ing fibers between cells and protein-lined ion channels that example, the triceps would be the antagonists to the biceps. allow action potentials to pass from cell to cell. For an action Smooth body movement depends on antagonists relaxing potential (an electrochemical cell signal or impulse) to occur, while prime movers&contract. Muscles may work opposite to © Jones Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the process needs a polarized cell, which is a cell at rest, waiteach other or together in orderOR to control various movements. NOT FOR SALE DISTRIBUTION FOR SALE OR DISTRIBUTION ing to reactNOT to a stimulus. Depolarization of the polarized cell requires a trigger or minimum energy level. Depolarization opens channels into the cell, allowing sodium to rush in. Smooth Muscle When enough sodium is inside the awaiting cell, an action potential fires stimulating surrounding Smooth muscle cells are smaller than those of skeletal mus© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC cells. Repolarization is the recovery phase that follows depolarization. During this cle. They are spindle-shaped with a single nucleus. Smooth NOT FOR SALE DISTRIBUTION FOR sodium SALE leaves OR DISTRIBUTION the cell via active transport, allowing muscle cells OR contain fewer actin and myosin myofilamentsNOT phase

6

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the cell to return to a polarized state awaiting the next stimmeans OR “long.” The adductor brevis muscle is a NOT longus FOR SALE DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

ulus. short muscle that adducts the thigh. One of its synergists, Cardiac muscle has the property of intrinsic automaticity, the adductor longus, is a long muscle that performs the meaning that, to an extent, it is able to generate its own elecsame task. trical activity. Depolarization of cardiac muscle results from the In Greek, the word deltoid translates as “triangular.” The Jonesions & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC influx of both sodium and©calcium across the cell memdeltoid muscle is a large triangular muscle of the arm and brane. Under the right conditions (electrolyte abnormality, shoulder. In Latin, the term NOT rectus FOR means SALE “straight,” and the OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION sodium, potassium or calcium abnormalities, or hypoxemia), linear muscle of the abdomen is the rectus abdominis. The any cell in the heart can become irritable and begin giving off sternocleidomastoid muscle originates at the sternum and extrasystoles. It is these extrasystoles that can precede ventrictravels over the clavicle and then inserts into the mastoid ular fibrillation. process. The biceps muscle of the arm has two heads. © Jones & Bartlett Learning, LLC © Jones & Bartlett The anterior and posterior viewsLearning, of the superfiLLC cial skeleFigure 4-8 Figure 4-9 . tal musclesNOT are shown NOT FOR SALE OR DISTRIBUTION FORinSALE ORand DISTRIBUTION

6

Muscular Anatomy

The Head, Trunk, and Upper Extremity

It is important for you to know the muscle groups, their The Head locations, and their functions. Names of muscles often The muscles that enable head movement describe their sizes, shapes, locations, actions, number of© Jones © Jones & Bartlett Learning, LLC & Bartlett Learning, LLC are located in the anterior, posterior, and lateral aspects of the skull. As a rule, attachments, or direction of fi bers. For example, the word NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION most of these muscles originate at the upper cervical vertepectoralis means “chest” in Latin. The major muscle of brae and insert in the skull, most often the occipital bone the chest wall is the pectoralis major. The word “angina” Figure 4-10 . Innervation is provided by cervical roots C1 means pain, thus angina pectoralis is “pain in the chest.” and C2, as well as the spinal accessory nerve. The word brevis means “short” in Latin; and the word

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Case Study PART 2

You suspect that the patient has sustained an injury to the ligaments that hold the knee joint together. You ask the patient and her& father, who has been at herLLC side since moments after the occurred, about her history, revealing © Jones Bartlett Learning, © injury Jones & Bartlett Learning, LLC thatNOT the patient is a 14-year-old girl who weighs 49 kg. Her SAMPLE history shows the following: FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Signs and symptoms: Swelling, pain, tenderness, and distal muscular motor weakness secondary to pain in the injured extremity ■ Allergies to medications: No known drug allergies ■ Medications taken: Ibuprofen, vitamin C © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ■ Past pertinent medical history: Previously injured right knee while alpine skiing and fractured right wrist while NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION skateboarding ■ Last food/fluid intake: A few orange slices during the last break, otherwise no food since breakfast ■ Events prior to onset: Noncontact injury involving rapid deceleration and rotation of the right knee ■

Recording Time:© 5 Jones Minutes&

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3. In addition to tendons, what other structures in and around the knee may have been injured? What types of knee injuries situation? © Jones & 4. Bartlett Learning, LLC are most common in this © Jones & Bartlett Learning, LLC NOT FOR SALE NOT FOR SALE OR DISTRIBUTION 5. WhatOR are DISTRIBUTION your concerns for management of this injury?

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Sternocleidomastoid Pectoralis minor

Levator scapulae

© Jones & Bartlett Learning, LLC Platysma NOT FOR SALE OR DISTRIBUTION Trapezius Deltoid

Pectoralis major Serratus anterior

Deltoid

Biceps brachii

Triceps brachii

© Jones & Bartlett Learning, LLC External abdominal NOT FOR SALE OR DISTRIBUTION oblique

External intercostals

Splenius

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Latissimus © Jones & Bartlett Learning, LLC dorsi NOT FOR SALE OR DISTRIBUTION

Extensor carpi radialis longus

Rectus abdominis

Brachioradialis

© Jones & Bartlett Learning, LLC Tensor NOT FOR SALEfasciae OR DISTRIBUTIONAdductor latae

Sartorius Gracilis

longus

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Rectus femoris

Adductor magnus

Vastus medialis Vastus lateralis

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Gastrocnemius

Tibialis anterior

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Biceps femoris

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Peroneus longus

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Gluteus maximus

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Located anteriorly, both the longus capitis and rectus of both eyeballs coordinate, so that eye movements occur in © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC capitis muscles rotate and flex the head. Numerous postesynchrony. NOT FOR ORbyDISTRIBUTION NOT FOR SALE OR DISTRIBUTION rior muscles assist in rotation and extension of the head. Muscles of mastication (chewing) areSALE innervated the Laterally, the sternocleidomastoid muscles rotate and extend fifth cranial nerve. The temporalis muscle elevates and retracts the head, whereas the rectus capitis lateralis abducts it. the mandible, as does the masseter. The lateral and medial pterygoid muscles perform the opposite action, depressing The Face the mandible. The tongue contains several muscles that also © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The skeletal muscles of the face are superficial and attach to are very important in both chewing and speech Figure 4-12 . SALE OR facial DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the skin.NOT They FOR originate on various bones and, with one Swallowing is a complex process that involves coordiexception, are innervated by the seventh cranial nerve, the nated contraction of numerous muscles of the palate, pharfacial nerve. The exception, the levator palpebrae superioris, ynx, and larynx. Many of these muscles are innervated by is innervated by the third cranial nerve, the oculomotor nerve the recurrent laryngeal nerve. Figure 4-11 . © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The Shoulder and Back Six muscles attach to the eyeball, allowing it to rotate NOT FOR SALE OR DISTRIBUTION FOR SALE ORposterior DISTRIBUTION muscles of the thorax form the first layer of back within the orbit in many directions. These muscles areNOT The muscles. These include the trapezius, deltoids, rhomboids, innervated by the oculomotor nerve. The motions of muscles © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION.

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Rectus capitis lateralis

Rectus capitis anterior © Jones

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© Jones Longus colli

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Longus capitis

Sternocleidomastoid

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Clavicle

© Jones & Bartlett Learning, LLC NOT FOR SALE ORManubrium DISTRIBUTION of sternum

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

Pathophysiology The term whiplash describes aLearning, neck injury associated © Jones & Bartlett LLC with NOT suddenFOR flexionSALE or extension and resulting in pain OR DISTRIBUTION or other evidence of injury. Typically, a hyperextension-hyperflexion injury of the cervical spine occurs as a result of a rear-end collision. The patient reports neck and head pain, which may radiate down either arm. At times, concomitant stimulation of the sympathetic nervous system may result in dizziness, © Jones & Bartlett Learning, LLC blurred vision, or behind the eyeballs. In the absence of fracture, NOT FORpain SALE OR DISTRIBUTION dislocation, or neurologic injury, symptoms typically resolve spontaneously within 6 to 8 weeks, and longterm impairment is rare.

Occipitofrontalis

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Procerus

Levator labii superioris alaeque nasi

© JonesTemporalis & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Obicularis oculi

Levator labii superioris Zygomaticus minor

© Jones & Bartlett Learning, LLCZygomaticus major NOT FOR SALE OR DISTRIBUTION

Pathophysiology

Levator anguli oris

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Masseter

Bell palsy is a condition that results from dysfunction

of the facial nerve, as a result of either trauma or infecJones Bartlett Learning, tion.© The patient&becomes unable to move LLC the facial muscles onFOR the affected the lip sags during NOT SALEside, ORand DISTRIBUTION speech and attempts at smiling. The most significant problem that results from Bell palsy is that the patient often is unable to close his or her eyelid and loses the protective blinking reflex. To protect the eye, patients can instill artificial tears or keep the eyelid taped shut. © Jones & Bartlett Learning, LLCpersons, at least to a Nerve function returns in most few weeks. NOT FORdegree, SALEwithin OR aDISTRIBUTION

Buccinator Obicularis oris

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Depressor anguli oris

Depressor labii inferioris Mentalis Platysma

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© Jones & Bartlett Learning, LLC vertebrae to the ribs. These muscles often are referred NOT from FORtheSALE OR DISTRIBUTION

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to as the back muscles. Various spinal nerves innervate all of the back muscles, depending on the muscle’s location. Collectively, the erector spinae form the largest group of superficial back muscles. This group is subdivided into three © Jones & Bartlett Learning, LLC © Jonesand & Bartlett Learning, LLC groups: the iliocostalis, longissimus, spinalis muscles. The longissimus group provides greatest muscle mass NOT the FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION and strength in the back. Styloid process Deep muscles of the back include the interspinales musTongue cles, which connect the spinous processes of all vertebrae; the intertransversarii muscles, which connect the transverse proStyloglossus Mandible © Jones & Bartlett Learning, LLC © Jones & Bartlett cesses; the multifi dus muscles, which Learning, help erect andLLC rotate the Hyoglossus spine; the rotatores, which lie deep in the groove between the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION spinous and transverse processes of the vertebrae and extend Genioglossus and rotate the vertebral column toward the opposite side; and Larynx Geniohyoid the semispinalis muscles, which help to rotate the spine.

© Jones & Bartlett Learning, LLC NOT FORTrachea SALE OR DISTRIBUTION

Hyoid

© Jones & Bartlett Learning, LLC Clinical Tip NOT FOR SALE OR DISTRIBUTION

Injury to even one of the smallest deep back muscles can result in spasm. Once started, the process tends to spread and involve surrounding tissues. Inflammation is common with muscle spasm. These conditions © Jones & Bartlett Learning, LLCalso © Jones & Bartlett Learning, LLC often are treated with a combination of pain mediNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION cations and anti-inflammatory and anti-spasm (muscle relaxing) agents. Nonsteroidal anti-inflammatory Pathophysiology drugs such as ibuprofen are the most common type of anti-inflammatory agents used for back pain and spasm. Laryngeal spasm (spasm of the muscles of the larynx) Depending on local protocols, severe muscle spasm in can occur following severe allergic reactions. If swelling the prehospital setting may be treated with a combina© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC is severe enough, it can block passage of air into the tion of pain medication (such as morphine) and muscle NOT FORthis SALE OR isDISTRIBUTION NOT SALE OR DISTRIBUTION trachea. Unless condition promptly corrected, relaxants (suchFOR as diazepam). hypoxia can cause brain damage or death.

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Clinical Tip

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Sprains and strains of the lower back are often sustained

by EMS providers and usually are caused by repetitive lifting or straining of the lower back muscles, tendons, Clinically, oculomotor nerve function is evaluated by and ligaments. Sprains and strains sometimes can occur having the patient move the eyes in various directions— after a single attempt at trying to lift an object that is right, left, up, down, and at 45º angle combinations because&ofBartlett poor posture © Jones LLCtoo heavy, or they can occur © Jones Learning, LLC (eg, up and to the right, down and&toBartlett the left). Learning, These or lifting techniques. In a business in which the EMS are called the extraocular . The easiest NOT FOR SALE OR DISTRIBUTION NOT movements FOR SALE OR DISTRIBUTION provider has to lift and move people who can and will way to evaluate the extraocular movements is to ask be found in the most unusual places and positions, it the patient to follow a fingertip or flashlight with his or is essential that good lifting mechanics are used at all her eyes. Normally, both eyes should move the same times to help prevent back injuries from occurring. amount in each direction. The pain from sprains and strains of the lower back sometimes is described as soreness and achingLLC and is © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, localized over the lower part ofOR the back. The pain often NOT FOR SALE OR DISTRIBUTION NOT FOR SALE DISTRIBUTION is severe and, at times, a sharp pain may occur with sudden movements such as twisting or bending to pick and latissimus dorsi. All of these muscles are involved in something up. The pain sometimes is relieved by lying flat on the back or with the use of heat or ice. The pain motion of the upper thorax and shoulder girdle (see Figures from back spasm alone does not travel down the leg 4-8 and 4-9). © Jones & Bartlett Learning, LLC © Jonesor& Bartlett Learning, LLC cause numbness or weakness. The pain may last for Two groups of muscles move the spine: deep muscles and several weeksOR or longer. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE DISTRIBUTION

superficial muscles. The deep muscles originate and insert from vertebra to vertebra, whereas the superficial muscles run

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87

© Jones & Bartlett Learning, LLC by spinal nerves. The trapezius muscle receives NOT innervated FOR SALE OR DISTRIBUTION

innervation from the 11th cranial nerve, the spinal accesDuring breathing, the major movement is produced by consory nerve. traction of the diaphragm, a flattened dome-shaped muscle The pectoralis major and latissimus dorsi muscles attach located at the base of the thoracic cavity. The phrenic nerve the arm to the thorax. The rotator cuff is a special group innervates the diaphragm. Damage to this nerve can result © Jones LLC Jones & over Bartlett Learning, LLC of four muscles that forms © a cuff or cap the proximal in difficulty breathing. Other muscles&ofBartlett respirationLearning, include humerus, attaches the humerus to FOR the scapula, andOR provides the scalene muscles, which elevate theSALE first twoOR ribsDISTRIBUTION during NOT SALE DISTRIBUTION NOT FOR for rotation of the arm. inspiration, and the external and internal intercostal muscles Numerous other muscles are involved in movements of Figure 4-13 . the arm. Major flexors include the deltoid and biceps brachii muscles. The triceps brachii and deltoid muscles are primar© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ily responsible for extension of the arm. Abduction, adducPathophysiology tion, and medial and lateral rotation are caused by actions NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION of the triceps brachii and deltoid muscles, as well as several other accessory muscles Figure 4-14 . Hiccups occur when there is irritation of the phrenic nerve, resulting in sudden and unpredictable contracMuscles acting on the forearm include those of the arm, tions of the diaphragm. as noted above, as well as intrinsic muscles of the forearm. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The anconeus muscle stabilizes the elbow in extension; the NOT FOR SALE OR DISTRIBUTION NOT brachioradialis FOR SALE OR flexesDISTRIBUTION it. Both the pronator quadratus and pronator teres muscles pronate the forearm, whereas the supinator muscle supinates the forearm. The Abdomen Hand, wrist, and finger movements are primarily mediThe abdominal muscles, which consist of both superfiated by muscles in the forearm. These muscles are divided cial and deep layers of muscles, flex&and rotate the spine. © Jones Bartlett Learning, LLC © Jones & Bartlett Learning, LLC into extensor muscles, groups of muscles that cause extenA  tendinous area knownNOT as theFOR linea SALE alba liesOR in the midSALE that OR cause DISTRIBUTION DISTRIBUTION sion, and flexor muscles, NOT groupsFOR of muscles line. The muscles originate along the pelvic bones and the flexion when contracted. For example, the flexor digitoribs and insert in the same areas, depending on which musrum superficialis causes flexion of the fingers. As a rule, cle is involved. Spinal nerves provide innervation to the abdominal muscles.

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The Upper Extremity NOT FOR SALE OR DISTRIBUTION Six muscle groups hold the scapula firmly against the body when the muscles of the arm contract. All originate on the upper vertebrae and ribs and insert onto various portions of the scapula. Except for the trapezius muscle, all are

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Deltoid Infraspinatus Teres major

Scalene muscles

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© Jones & Long Bartlett head ofLearning, LLC triceps brachii NOT FOR SALE OR DISTRIBUTION

External intercostals

Lateral head of triceps brachii

Pectoralis minor Internal intercostals Serratus anterior

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Medial head of

triceps brachii © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Common triceps tendon Olecranon

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Medial

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Lateral

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the extensor muscles originate on the lateral aspect of the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Pathophysiology elbow, and the flexor muscles originate on the medial side Figure 4-15 . Movement is also affected by the intrinsic muscles of Rotator cuff injuries are a common source of shoulder pain and often occur as a result of tendon degeneration the hand, the lumbricales and the interossei, as well as the As the& tendons weaken, © Jones & Bartlett Learning, LLCfrom age and repeated trauma. © Jones Bartlett Learning, LLC muscles of the thenar and hypothenar eminences, fleshy thickening and chronic infl ammation occur in the overprominences at the base of the thumb and fiDISTRIBUTION fth finNOT FOR SALE OR DISTRIBUTION NOT FOR (thenar) SALE OR lying shoulder bursa. Complete ruptures occasionally ger (hypothenar). These small muscles are located entirely occur during athletic events involving heavy lifting or a within the hand Figure 4-16 . All muscles that cause motion fall on an outstretched hand, but they occur far more of the hand and fingers are innervated by the median, ulnar, frequently as a result of chronic degeneration. Patients typically report pain and tenderness over the shoulor radial nerve. © Jones & Bartlett Learning, LLC NOT FORand SALE OR Extremity DISTRIBUTION The Pelvis Lower

der, which is worsened by abduction of the arm.LLC In the © Jones & Bartlett Learning, absenceNOT of complete tendon rupture, some strength is FOR SALE OR DISTRIBUTION maintained. With rupture, severe weakness and variable pain are both common. Radiographs often are normal; The Pelvic Floor and Perineum magnetic resonance imaging can help diagnose comThe coccygeus muscle and the levator ani muscle form plete and partial tears. Strains of the rotator cuff or tendinitis respond well to rest and treatment with nonthe floor of the pelvis. The area below these muscles is the © Jones & Bartlett Learning, LLC © Jones & Bartlett LLCTears may require steroidal anti-inflLearning, ammatory drugs. perineum. The structures of the urogenital system (somesurgical repair. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

times called the urogenital triangle) lie anteriorly; the structures of the anus, or anal triangle, lie posteriorly.

© Jones & Bartlett Learning, LLC BicepsDISTRIBUTION and NOT FOR SALE OR Medial epicondyle tendon

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of humerus

© Jones & Bartlett Learning, LLC Flexor muscles NOT FOR SALE OR DISTRIBUTION (medial) Extensor muscles

Anconeus

© Jones & Bartlett Learning, LLC Supinator NOT FOR SALE OR DISTRIBUTION Abductor pollicis longus

(lateral)

© Jones & Bartlett Learning, LLC NOT FORExtensor SALEtendons OR DISTRIBUTION

Flexor tendons©

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Extensor pollicis longus Extensor pollicis brevis Extensor indicis

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Hand

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Lateral

Medial

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION B

Medial

Lateral

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Pathophysiology

Bicipital tendinitis is a common cause of shoulder pain in adults older than 40 years; however, it also may use repeated throwing © Jones & Bartlett Learning, LLCoccur in younger athletes©who Jones & Bartlett Learning, LLC motions. The common denominator is inflammation of NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Interossei the biceps tendon, as well as its sheath, in the bicipital groove. Patients have pain over the anterolateral aspect of the shoulder, which often radiates down the arm. Palpation reveals tenderness in the bicipital groove of Lumbricales the humerus, and a positive Yergason test, supported by pain © in the bicipital on supination of the fore© Jones & Bartlett Learning, LLC Jones & groove Bartlett Learning, LLC arm against resistance. Radiographic studies most often NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION are normal. Treatment consists of rest, heat, range-ofmotion exercises, and nonsteroidal anti-inflammatory drugs. Sometimes, corticosteroids are injected into the shoulder. Surgery is a last resort. Hypothenar eminence

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Thenar eminence

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In males, the bulbospongiosus muscle constricts the urethra and aids in the erection of the penis; in females, it results in erection of the clitoris. &The orifice Learning, of the © Jones & Bartlett Learning, LLC © Jones Bartlett LLC anal  canal is kept closed by the sphincter ani externus, NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION whereas the urethral sphincter muscle constricts the urethra Figure 4-17 .

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Penis

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Bulbospongiosus Deep transverse perinei Learning, LLC

Vagina

Urogenital triangle

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Ischiocavernosus

Sphincter ani externus

Levator ani Anal triangle

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Sphincter ani externus

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Coccyx

A

Deep transverse

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Levator ani Anal triangle

Urethra Bulbospongiosus

Ischiocavernosus

Urogenital triangle

Clitoris

B

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cause flexion and rotation at the hip. Muscles of the medial The muscles of the hip cause movement of the thigh at the compartment, the adductor brevis, adductor longus, and hip joint. Many of these muscles originate in the pelvis and adductor magnus, the gracilis, and the pectineus muscles— insert on the femur. Various lumbar and sacral spinal nerves adduct, flex, and internally rotate the thigh Figure 4-18 . innervate this area. © Jones Bartlett Learning, LLC Movements at the knee © joint Jones Bartlett Learning, LLC are &effected by sets of Flexion of the hip occurs when&the iliopsoas muscle muscles located in two compartments the thigh, anacontracts. Posterolaterally,NOT the gluteal muscles OR (the DISTRIBUTION gluteus NOT FOR of SALE OR DISTRIBUTION FOR SALE tomic spaces that are enclosed by fascia. The anterior comminimus, medius, and maximus) and the tensor fasciae latae partment contains the quadriceps femoris and sartorius extend and rotate the hip. Deeper muscles, the gemellus,

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Inguinal ligament

Pectineus © Jones & Bartlett Learning, LLC NOT FORRectus SALE OR DISTRIBUTION Adductor

Gluteus maximus

femoris

longus

Gracilis

Vastus lateralis

Gracilis

Semitendinosus

Quadriceps tendon

A

minimus

Gluteus medius

Iliopsoas

Sartorius

Fascia lata

© Jones & Bartlett Learning, LLC Gluteus NOT Pelvis FOR SALE OR DISTRIBUTION Piriformis

© Jones & BartlettObturator Learning, LLC internus NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC Biceps SemiNOTVastus FOR SALE OR DISTRIBUTION femoris membranosus

Gemellus superior Femur

Gracilis

Gemellus inferior

Semitendinosus

Quadratus femoris

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Semimembranosus NOT

medialis Patella

Lateral

Medial Medial B © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

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Lateral

Lateral C © Jones &Medial Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION

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At this point, you and your team carefully splint the injury, making sure to apply ice to help control the swelling, and prepare the patient for transport to the hospital. The patient is alert and talking with her father. As you roll the patient off the field on your stretcher, all the andLearning, bystanders applaud. that she&appreciates © Jones & parents Bartlett LLC You can see on her face © Jones Bartlett Learning, their support, while at the same time, she appears anxious about her injury.

LLC NOT FOR SALE OR DISTRIBUTION

NOT FOR SALE OR DISTRIBUTION

Recording Time: 10 Minutes

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR 6. SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION What would be your next steps in assessing the patient?

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Chapter 4 The Musculoskeletal System

91

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC muscles. The quadriceps femoris muscle primarily extends Anatomically functionally, the leg contains four NOT FOR SALE ORand DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

the knee when it contracts. (Because portions of the quadcompartments: the anterior, the superficial posterior, the riceps femoris also cross the hip, a secondary function of deep posterior, and the lateral compartments. The anterior this muscle is flexion of the hip joint.) The sartorius muscompartment contains muscles that extend (or dorsiflex) cle is the longest muscle in the body, and it flexes the knee the ankle and toes. The superficial posterior compartment © Jones & Bartlett LLC Jones and & Bartlett Learning, LLC and the hip when it contracts. In the posterior Learning, compartcontains the gastrocnemius,©plantaris, soleus muscles, ment, the biceps femorisNOT muscleFOR flexesSALE and laterally rotates which are superficial muscles thatFOR plantar flex the NOT SALE ORankle. DISTRIBUTION OR DISTRIBUTION the knee and extends the hip. The semimembranosus and The Achilles tendon is the strong tendon that attaches these semitendinosus muscles flex and medially rotate the knee. muscles to the calcaneus. The deep posterior compartment Together, the biceps, semimembranosus, and semitendinocontains muscles that flex the toes and invert the foot and sus muscles are referred to as the hamstrings. ankle. The lateral compartment contains muscles that pri© Jones Learning, LLC Jones Muscles located&inBartlett the leg act on the ankle and foot. marily evert©the foot. & Bartlett Learning, LLC The intrinsic foot muscles within the foot These muscles typically originate on the tibia and fibula NOT FOR SALE OR DISTRIBUTION NOT FOR SALE are ORlocated DISTRIBUTION itself and are arranged similarly to the intrinsic muscles of and insert into the foot Figure 4-19 . The tibial and peroneal nerves, terminal divisions of the sciatic nerve, innervate the hand. They flex, extend, abduct, and adduct the toes Figure 4-20 . these muscles.

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© Jones & Bartlett Learning, LLC Plantaris OR DISTRIBUTION NOT FOR SALE

Patella

© Jones & Bartlett Learning, LLC Tibialis anterior NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Gastrocnemius

Gastrocnemius Peroneus muscles

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Soleus

Extensor muscles and tendons

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Achilles tendon

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Lateral

Medial

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© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Medial

Lateral

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92

Anatomy & Physiology for the Prehospital Provider, Second Edition

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Lumbricales

Pathophysiology

Each anatomic compartment of the leg is enclosed by fascia and is essentially a closed space. Following © Jones & Bartlett Learning, LLCtrauma, blood or fluid can © Jones & Bartlett Learning, LLC accumulate within a compartment, resulting in compression of the blood OR vessels NOT FOR SALE DISTRIBUTION NOT FOR SALE OR DISTRIBUTION and tissue damage secondary to ischemia, a condition known as compartment syndrome. If not recognized and promptly treated, compartment syndrome can Flexor hallucis cause death of muscle and loss of the limb. brevis

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Flexor digiti NOT minimi brevisFOR

Flexor digitorum brevis

Abductor digiti minimi

The Achilles tendon can be ruptured, usually following

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Insertion of plantar aponeurosis

Pathophysiology

Abductor hallucis

or overstretching activities © Jonesjumping & Bartlett Learning, LLC such as racquetball. Spontaneous rupture is rare. Following the injury, NOT FOR the SALE patient OR walksDISTRIBUTION flat-footed and is unable to stand

on the ball of the foot. Active plantar flexion is lost, although other muscles in the calf may allow some motion to remain. The Thompson test is a test that is used to evaluate the integrity of the Achilles tendon for foot,& theBartlett test normally © Jones & Bartlett Learning, LLCpossible rupture; in the uninjured © Jones Learning, LLC is positive—squeezing the calf results in plantar flexion NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION at the ankle. With a complete tear, the foot remains stationary. Treatment is occasionally surgical.

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Case Study PART 4

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En route to the hospital, you continue to take serial vital signs, which remain stable. You reassess the splint and reevaluate the patient’s distal pulse, motor, and sensory function. The application of ice has helped diminish the © Jones patient’s & Bartlett Learning, LLC Jones & tore Bartlett Learning, pain somewhat. You find out from the patient’s © father that he his anterior cruciateLLC ligament about 10 NOT FOR SALE OR DISTRIBUTION FOR DISTRIBUTION years ago at work and had it reconstructed, so he is veryNOT familiar with SALE this typeOR of injury.

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Skidplate: © Photodisc

Prep Kit

© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Chapter Summary

93

action potentials Changes in electrical potential that occur when a cell or tissue has been activated by a stimulus. ■ Muscles are classified as skeletal muscle (voluntary), adductor brevis The short muscle that adducts the thigh. smooth muscle© (involuntary), cardiac muscle. Jones & or Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ■ adductor longus The long muscle adducts the hip. Muscle fibers, NOT as wellFOR as connective tissue, blood NOTthat FOR SALE OR DISTRIBUTION SALE OR DISTRIBUTION vessels, and nerves, comprise the more than 350 agonist A prime mover; a muscle that contracts to provide voluntary skeletal muscles in the body. most of a desired movement. ■ Myofibrils, which are threadlike structures that anal triangle The area within the pelvis that contains the extend from one end of the muscle fiber to the other, anus. are located individual muscle cells. © Jones &within Bartlett Learning, LLC Jones & Bartlett Learning, LLC antagonists©Muscles working in opposition to each other. ■ A cell membrane each muscle fiber. As NOT FOR SALEsurrounds OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION aponeuroses Broad sheets of fibers that may attach to several muscle fibers are bundled with connective bones or to the coverings of other muscles. tissue, they form a muscle fasciculus. A complete Bell palsy A condition caused by damage, either through muscle consists of many fasciculi grouped together, trauma or infection, to the facial nerve, resulting in surrounded by the perimysium. an inability to move the facial muscles on the affected © Jones & Bartlett Learning, LLC & Bartlett Learning, LLC ■ One end of a skeletal muscle usually is fastened to© Jonesside. relatively immovable part (origin) at a movableNOT biceps NOT FOR SALEa OR DISTRIBUTION FOR SALE DISTRIBUTION femoris OR Located in the posterior compartment joint. The other end connects to one side of a movof the leg; flexes and laterally rotates the knee and able joint (insertion) on the other side of the joint. extends the hip. ■ Calcium and energy, from ATP, are important to the calmodulin An intracellular protein to which calcium binds, resulting in muscle contraction. contraction of muscles. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ■ cardiac muscle Muscle that is found only in the heart, There are two types of smooth muscle: visceral and NOTneeded FOR to SALE NOT FORare SALE OR DISTRIBUTION providing the contractions propelOR theDISTRIBUTION multiunit. Smooth muscles nonstriated and are blood through the circulatory system. involuntary. The smooth muscles are located in the digestive, reproductive, and urinary tracts, as well as compartment syndrome Accumulation of blood or fluid in a fascial compartment, typically following trauma, in the linings of blood vessels. resulting in compression of blood vessels and tissue ■ The autonomic nervous system innervates smooth © Jones & Bartlett Learning, LLC ©secondary Jones & Bartlettand, Learning, LLC damage to ischemia if not recognized muscle throughout the body. and promptly treated, death of muscle and loss of the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ■ The study of muscular anatomy involves underlimb. standing the placement of muscles and their funccompartments Anatomic spaces within the body that are tion in moving bones. enclosed by fascia. ■ Synergists are muscles that work together to accomcreatine phosphate An organic compound in muscle tisplish Learning, a particular movement; antagonists are mus-© Jonessue can store and provideLLC energy for muscle con© Jones & Bartlett LLC & that Bartlett Learning, cles that work in opposition to one another. traction. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ■ Specific muscles are key to the movement of the depolarization The rapid movement of electrolytes across a cell membrane that changes the cell’s overall charge. head, face and eyes, back, thorax, abdomen, pelvis, This rapid shifting of electrolytes and cellular charges and the upper and lower extremities. is the main catalyst for muscle contractions and neural transmissions. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Vital Vocabulary diaphragm A muscular dome that forms the undersurNOT FOR SALE NOT FOR SALE OR DISTRIBUTION face of the thorax, separating the chest fromOR theDISTRIBUTION abdominal cavity. Contraction of the diaphragm acetylcholine A chemical neurotransmitter that serves as (and the chest wall muscles) brings air into the a mediator in both the sympathetic and parasympalungs. Relaxation allows air to be expelled from the thetic nervous system. lungs. acetylcholinesterase The enzyme that causes muscle ©relaxation Jones by & helping Bartlett Learning, LLC © Jones & Bartlett LLC endomysium The delicate connectiveLearning, tissue surrounding to break down acetylcholine. individual muscular fi bers. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Achilles tendon The strong tendon that joins the muscles epimysium A layer of connective tissue that closely surin the posterior leg to the calcaneus. rounds skeletal muscles. actin The component that makes up most of the thin proextensor muscles Groups of muscles that cause extension. tein filaments of the myofibrils.

6

6

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Prep Kit, continued Skidplate: © Photodisc

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION extracellular fluid Fluid outside of the cells, in which nerve impulse Electrochemical changes transmitted by

most of the body’s supply of sodium in contained; neurons to other neurons and to cells outside the neraccounts for 15% of body weight. vous system. extraocular movements Movement of the eyes in various neuromuscular junction The junction between a motor directions. type of&a Bartlett synapse. Learning, LLC © Jones & Bartlett Learning, LLC neuron and a muscle fiber; © one Jones fascia A layer of fibrous tissueOR outside the neurotransmitters Chemical NOT substances that transmit FOR SALE OR DISTRIBUTION NOTconnective FOR SALE DISTRIBUTION epimysium that separates individual muscles and nerve impulses across a synapse. individual muscle groups. origin A relatively immovable part of the body where a flexor muscles Groups of muscles that cause flexion when skeletal muscle is fastened at a moveable joint. contracted. oxygen debt The amount of oxygen that liver cells need to gap©junctions areas between cells (eg, in visconvert©lactic acid into glucose, asLearning, well as the amount JonesConduction & Bartlett Learning, LLC Jones & Bartlett LLC ceral smooth muscle) that interconnect individual needed by muscle cells to restore adenosine triphosNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION muscle cells. phate and creatine phosphate levels. hemoglobin An iron-containing protein within red blood pectineus muscles Deep muscles of the medial compartcells that has the ability to bind to oxygen. ment that adduct, flex, and internally rotate the thigh. insertion A moveable part of the body to which a skeletal pectoralis major The largest muscle of the chest wall; it muscle Learning, is fastened at aLLC moveable joint. and internally rotates LLC the shoulder. © Jones & Bartlett © Jonesadducts & Bartlett Learning, intercalated disks Branching fi bers in cardiac muscle that perimysium The connective tissue sheath that surrounds NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION allow action potentials to pass from cell to cell. a muscle and forms sheaths for the bundles of muscle fibers. intrinsic automaticity The ability of a muscle to generate its own electrical activity. perineum The area below the coccygeus and levator ani muscles, which forms the floor of the pelvis. lactic acid A metabolic end product of the breakdown of © Jones & Bartlett Learning, LLC Jones Bartlett Learning, LLC glucose that accumulates when metabolism proceeds polarized When a cell is at © rest, ions are&actively transin the absence ofNOT oxygen. ported into and out of the cell to create an electroNOT FOR SALE OR DISTRIBUTION FOR SALE OR DISTRIBUTION chemical gradient across the cell membrane. motor end plate The flattened end of a motor neuron that transmits neural impulses to a muscle. prime mover The muscle in a group of muscles that has the major role in movement. motor neurons Specialized nerve cells that deliver an impulse to muscle cells, causing them to contract. quadriceps femoris Muscle contained in the anterior compartment of the thigh that extends the knee LLC when © Jones & Bartlett Learning, © Jones & Bartlett Learning, motor unit A motor neuron and the muscleLLC fibers that it contracted. controls. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION rectus abdominis The linear muscle of the midline of the multiunit smooth muscle One of the two types of smooth abdomen. muscle, it is formed into sheets of muscle (as in the walls of blood vessels), small bundles of muscles (as repolarization The process by which ions are moved in the iris of the eye), or single cells (as in the capsule across the cell wall to return to a polarized state. of the spleen). © Jones & Bartlett Learning, LLC © Jones Bartlett Learning, LLC rotator&cuff A special group of four muscles that forms a muscle Fibers that contract causing movement; threeNOT FOR capSALE over theOR proximal humerus and ties the humerus NOT FOR SALE OR DISTRIBUTION DISTRIBUTION types of muscle are present in the body: skeletal musto the scapula; it controls rotation at the shoulder cle, smooth muscle, and cardiac muscle. joint. muscle fasciculus A bundle of skeletal muscle cells bound sarcolemma The thin transparent sheath surrounding a together by connective tissue and forming one of the striated muscle fiber. constituent elements of a muscle. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC sarcomeres The repeating patterns of striation units that muscle impulse OneNOT that FOR passesSALE in many appear along each skeletalNOT muscle fiber.SALE OR DISTRIBUTION FOR ORdirections DISTRIBUTION over a muscle fiber membrane after stimulation by sarcoplasmic reticulum A system of membranes that acetylcholine. transport materials in muscle cells. musculoskeletal system The bones and voluntary muscles sartorius muscle The longest muscle in the human body, of the body. it is located in the anterior compartment of the thigh myofi Threadlike structures that extend from one and flexes both the& hipBartlett and knee when it contracts. © brils Jones & Bartlett Learning, LLC © Jones Learning, LLC end ofFOR the muscle fiber to the other. scalene muscles of respiration that elevate the NOT SALE OR DISTRIBUTION NOT Muscles FOR SALE OR DISTRIBUTION myoglobin An iron-containing red pigment, similar to first two ribs during inspiration. hemoglobin, that is found in muscle fibers. skeletal muscle Striated muscles that are under direct myosin The component that makes up most of the thick volitional control of the brain; also called voluntary protein filaments of the myofibrils. muscle.

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Prep Kit, continued

Skidplate: © Photodisc

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORAnswer: SALE Skeletal OR DISTRIBUTION NOT FOR SALE DISTRIBUTION sliding fiOR lament model A method of action of muscle muscle comprises 40% of the

95

contraction involving how sarcomeres shorten, with body’s weight and is responsible for most volunthick and thin filaments sliding past each other tary body movements. The body contains more toward the center of the sarcomere from both ends. than 350 skeletal muscles. smooth muscle Nonstriated muscle that carries out much Jones Bartlett Learning, LLC3. In addition to tendons, © what Jones & structures Bartlett in Learning, LLC other of the automatic©work of the&body, such as moving and around the knee may have beenSALE injured?OR DISTRIBUTION NOT FOR FOR OR and DISTRIBUTION food through theNOT digestive tractSALE and dilating constricting the pupils of the eye; also called involuntary Answer: The knee is unusual in that it contains muscle. ligaments within the joint. It is traditionally classtriations Areas of alternating, colored bands of skeletal sified as a hinge joint. The knee is surrounded muscle fiber. by several fluid-filled bursae. The distal end of © Jones & Bartlett Learning, LLCcommu© Jones & Bartlett synapse A functional connection where neurons the femur articulates with theLearning, condyles ofLLC the nicateFOR with other cells.OR DISTRIBUTION NOT SALE NOT FOR SALE OR DISTRIBUTION proximal tibia. The C-shaped lateral and medial synaptic cleft The space between neurons. menisci are cartilage pads that act as cushions between the femur and tibia. The patella, a flat trisynergists Muscles that work together to accomplish a particular movement. angular movable bone, covers the anterior surface of the joint. Tough, ropelike cords © Jones & tendons Bartlett Learning, LLCof fibrous tissue that attach© Jones & Bartlett Learning, LLC muscles to bones. 4. What types of knee injuries are most common in NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Thompson test A test used to evaluate the integrity of the this situation? Achilles tendon for possible rupture. Answer: Cartilage and ligament injuries of the transverse tubules T-tubules; membranous channels knee are relatively common. The anterior and extending inward and passing through muscle fibers. posterior cruciate ligaments prevent abnormal tropomyosin An actin-binding protein that Learning, regulates © Jones & Bartlett LLC motion of the knee from © Jones & Bartlett Learning, LLC front to back, while the muscle contraction and other actin-related mechanNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONmedial and lateral collateral ligaments stabilize ical function of the body. the joint against abnormal side-to-side motions. troponin A regulatory protein in the actin filaments of skelWhen these structures are injured, abnormal etal and cardiac muscle that attaches to tropomyosin. motions can occur. urogenital triangle The region within the pelvis that con5. What are your concerns for management of this the structures of the Learning, urogenital system. ©tains Jones & Bartlett LLC © Jones & Bartlett Learning, LLC injury? visceral of muscle found in the NOTsmooth FOR muscle SALE Sheets OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Answer: An injury to the knee joint is potendigestive, reproductive, and urinary tracts. tially serious. Bleeding, swelling, and nerve whiplash A layman’s term for traumatic soft-tissue injury impingement can occur, and if the injury is not to the structures of the neck, associated with sudden managed properly, the joint may be permanently flexion or extension. damaged. Proper positioning, testLearning, Supination of the forearm against resistance© Jones & © Jones & Yergason Bartlett LLC Bartlett Learning, LLCwith elevation if possible, and the immediate application of ice to to evaluate whether a patient has bicipital tendinitis. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

help reduce bleeding, swelling, and pain are the important initial steps in managing an injury to Case Study Answers the knee. 6. What would be your next steps in assessing the 1. What type of muscle is involved in the function of © Jones & Bartlett Learning, LLC patient? © Jones & Bartlett Learning, LLC a joint such as NOT the knee? FORisSALE FOR SALE OR DISTRIBUTIONAnswer: The patient’sNOT condition stable, OR withDISTRIBUTION Answer: Striated or skeletal muscle produces an isolated extremity injury; therefore, your reasmotion around a joint such as the knee. These sessment should include repeating the primary voluntary muscles are composed of muscle fibers, assessment, repeating and recording the patient’s connective tissue, blood vessels, and nerves. vital © signs every & 15Bartlett minutes, and reassessing the © Jones & Bartlett Learning, LLC Jones Learning, LLC 2. What is the primary function of the type of mussplint and distal pulse, motor, and sensory funcNOT FOR around SALEthe OR DISTRIBUTION SALEextremity. OR DISTRIBUTION cle found knee? tion NOT (PMS) FOR of the injured

6

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