Muscular System Chapter 9

Orthopedics The medical specialty that studies the anatomy and physiology of the muscular and skeletal systems and uses laboratory and diagnostic tests, medical and surgical procedures, and drugs to treat muscular and skeletal diseases.

Figure 9-1 Muscular system.

Anatomy and Physiology The muscular system moves the bony framework of the body. There are approximately 700 skeletal muscles in the body, as well as tendons and other structures of the muscular system.

Figure 9-2 Types of muscle.

Anatomy of the Muscular System Types of Muscles: Skeletal muscles Provide the means by which the body can move Are voluntary muscles that contract and relax in response to conscious thought Are striated Of the three types of muscles, only skeletal muscle belongs to the muscular system.

Anatomy of the Muscular System Types of Muscles: Cardiac Muscle Cardiac muscle of the heart pumps blood through the circulatory system. An involuntary muscle that is not under conscious control

Anatomy of the Muscular System Types of Muscles: Smooth Muscles Involuntary, nonstriated muscles Form a continuous, thin layer around many organs and structures (blood vessels, intestines, etc.)

Muscle Origins, Insertions, and Related Structures A muscle is attached to a bone by a tendon, a cordlike, non-elastic, white fibrous band of connective tissue. The origin or beginning of a muscle is where its tendon is attached to a stationary or nearly stationary bone. The insertion or ending of a muscle is where its tendon is attached to the bone that moves when the muscle contracts and relaxes.

Figure 9-3 Tendon.

Figure 9-4 Origin and insertion of a muscle.

Muscle Names 9-1 Muscle names are in Latin. They describe where the muscle is located, its shape, its size, or what action it performs.

Types of Muscle Movement Muscles function in antagonistic pairs to produce movement. These are opposite movements controlled by muscle pairs: Flexion and extension Abduction and adduction Rotation to the right and to the left Supination and pronation Eversion and inversion

Table 9-2 Types of Muscle Movement Description Muscle Type Pronunciation/Word Parts flexion Bending a joint to decrease the angle between two bones or two body parts. (Note: Plantar flexion of the foot causes the toes to point downward. Dorsiflexion of the foot causes the toes to point upward.) flexor flexion (FLEK-shun) flex/o- bending -ion action; condition flexor (FLEK-sor) -or person who does; person who produces; thing that does; thing that produces extension Straightening and extending a joint to increase the angle between two bones or two body parts extensor extension (eks-TEN-shun) extens/o- straightening extensor (eks-TEN-sor)

Table 9-2 Types of Muscle Movement Description Muscle Type Pronunciation/Word Parts abduction Moving a body part away from the midline of the body abductor abduction (ab-DUK-shun) ab- away from duct/o- bring; duct; move -ion action; condition abductor (ab-DUK-tor) -or person who does; person who produces; thing that does; thing that produces adduction Moving a body part toward the midline of the body adductor adduction (ad-DUK-shun) ad- toward adductor (ad-DUK-tor)

Pronunciation/Word Parts Movement Description Muscle Type Pronunciation/Word Parts rotation Moving a body part around its axis rotator rotation (roh-TAY-shun) rotat/o- rotate -ion action; condition rotator (ROH-tay-tor) -or person who does; person who produces; thing that does; thing that produces supination Turning the palm of the hand anteriorly or upward. (Note: Here, lying on the back refers to the back of the hand.) supinator supination (soo-pih-NAY-shun) supinat/o- lying on the back supinator (SOO-pih-nay-tor) pronation posteriorly or downward. (Note: Here, face down refers to the face of the palm.) pronator pronation (proh-NAY-shun) pronat/o- face down pronator (proh-NAY-tor) 9-1

Pronunciation/Word Parts Movement Description Muscle Type Pronunciation/Word Parts eversion Turning a body part outward and toward the side evertor eversion (ee-VER-zhun) e- out; without vers/o- travel; turn -ion action; condition evertor (ee-VER-tor) vert/o- travel; turn -or person who does; person who produces; thing that does; thing that produces inversion Turning a body part inward invertor inversion (in-VER-zhun) in- in; not; within invertor (in-VER-tor)

Figure 9-5 Extension, abduction, and dorsiflexion.

Figure 9-6 Extension, adduction, pronation, abduction, flexion, and plantar flexion.

Figure 9-7 Rotation.

Figure 9-8 Extension, supination, abduction, flexion, and inversion.

Figure 9-9 Muscles of the head and neck.

Figure 9-10 Muscles of the shoulder and chest.

Figure 9-11 Muscles of the shoulder and back.

Muscles of the Upper Extremity Biceps brachii Triceps brachii Brachioradialis Thenar muscles

Muscles of the Abdomen External abdominal oblique Internal abdominal oblique Rectus abdominis

Muscles of the Lower Extremity Quadriceps femoris is a collective name for the group of four muscles on the anterior aspect of the thigh: Rectus femoris Vastus lateralis Vastus intermedius (beneath the vastus lateralis) Vastus medialis

Muscles of the Lower Extremity Hamstrings is a collective name for the group of three muscles on the posterior aspect of the thigh: Biceps femoris Semitendinosus Semimembranosus

Figure 9-15 Muscles of the lower extremity.

Figure 9-17 Parts of a muscle. 9-2

Diseases 9-3 Diseases of the Muscles Atrophy- no muscle development- AKA muscle wasting Avulsion- muscle tears away from tendon Contracture- muscle becomes progressively flexed. ROM exercises are needed

Figure 9-19 Muscle contracture. 9-3

Diseases 9-3 Diseases of the Muscles Muscle contusion- bruise Muscle spasm- muscle cramp- sudden involuntary contraction of muscle Muscle strain- pulled muscle- overstretching a muscle

Diseases 9-3 Movement Disorders Ataxia-incoordination of muscles during movement Bradykinesia- slow muscle movement Dyskinesia- difficulty controlling the voluntary muscle movement- see in Parkinson’s & cerebal palsy Tetany- constant muscle contraction

Medical and Surgical Procedures 9-3 Medical and Surgical Procedures Medical Procedures Braces and adaptive devices Deep tendon reflexes (DTR)

Figure 9-22 Braces. 9-3

Figure 9-23 Deep tendon reflex. 9-3

Figure 9-24 Active exercise. 9-3