MED TERM Chapter 9 PDF

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MEDICAL TERMINOLOGY: Chapter 9 Orthopedics: Muscular System

Objectives of Chapter 9: 1. Identify structures of the muscular system. 2. Describe the process of muscle contraction and how muscles produce movement. 3. Describe common muscular diseases, laboratory and diagnostic procedures, medical and surgical procedures, and drugs. 4. Form the plural and adjective forms of nouns related to orthopedics (muscular). 5. Give the meanings of word parts and abbreviations related to orthopedics (muscular). 6. Divide orthopedics (muscular) words and build orthopedics (muscular) words. 7. Spell and pronounce orthopedic (muscular) words. 8. Research sound-alike and other orthopedic (muscular) words. 9. Analyze the medical content and meaning of orthopedic (muscular) reports.

Anatomy and Physiology The muscular system is the engine that 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. The contours of some skeletal muscles are visible under the skin, particularly when they contract. Others are located more deeply, and their movements may be felt. The purpose of the muscular system is to produce body movement. All of the muscles of the body (or the muscles in a particular part of the body) are referred to as the musculature. The muscular system is also known as the musculoskeletal system because of the close relationship between the muscles and the bones. Without the muscles, the bones would not be able to move and, without the bones, the muscles would lack support.

Anatomy of the Muscular System Types of Muscles There are three types of muscles: skeletal muscles, the cardiac muscle, and smooth muscles. o

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Skeletal muscles: Skeletal muscles provide the means by which the body can move. Skeletal muscles are voluntary muscles that contract and relax in response to conscious thought. They are striated, have multiple nuclei, and show bands of color when seen under a microscope. Cardiac muscle: The cardiac muscle of the heart pumps blood through the circulatory system. It is an involuntary muscle that is not under conscious control. Smooth muscles: Smooth muscles are involuntary, nonstriated muscles. They form a continuous, thin layer around many organs and structures (blood vessels, bronchi, intestines, etc.). Smooth muscles are discussed in various chapters.

Of the three types of muscles, only skeletal muscle belongs to the muscular -system. In the rest of this chapter, the word muscle should be understood to mean -skeletal muscle.

Muscle Origins, Insertions, and Related Structures A muscle is attached to a bone by a tendon , a cordlike, nonelastic, 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. The belly of a muscle is where its mass is the greatest, usually midway between the origin and insertion. From its origin on a bone, the muscle often travels across a joint; this is the joint that will move when the muscle contracts. A bursa, a thin sac of synovial membrane filled with synovial fluid, acts as a cushion to reduce friction where a tendon rubs against the bone near a synovial joint. Each muscle is wrapped in fascia , a thin connective tissue that joins with the tendon. An aponeurosis is a wide, white fibrous sheet of connective tissue, sometimes composed of several tendons, that attaches a flat muscle to a bone or to other, deeper muscles. A retinaculum is a nearly translucent band of fibrous tissue and fascia that holds down tendons that cross the wrist and ankle.

Muscle Names Muscle names can seem complex because they are in Latin, but you will recognize some of the Latin words because they relate to the bones studied in Chapter 8. Other Latin words become familiar because they consistently describe where the muscle is located, its shape, its size, or what action it performs. Muscle Name Biceps Brachii

What the Muscle Name Tells You Shape: Origin of the muscle has two parts or heads (biceps)

Extensor Digitorum

Location: Arm (brachii) Location: Radial bone (radi/o -) in the arm (brachi/o-) Action: Extends

Flexor Hallucis Brevis

Location: Digits (digitorum) Action: Flexes

Brachioradialis

Location: Big toe (hallux)

Gluteus Maximus

Size: Short (brevis) Location: Buttocks (gluteus)

Rectus Abdominis

Size: Large (maximus) Orientation: Straight up and down (rectus)

Temporalis Triceps Brachii

Location: Abdomen (abdominis) Location: Temporal bone (temporalis) of the cranium Shape: Origin of the muscle has three parts or heads (triceps) Location: Arm (brachii)

Types of Muscle Movement Muscles function in antagonistic pairs to produce movement. When the first muscle contracts, the second muscle relaxes to allow the movement or it partially contracts to control the movement. Flexion and extension, abduction and adduction, rotation to the right and to the left, supination and pronation, and eversion and inversion are opposite movements that are controlled by muscle pairs. Movement Flexion

Extension

Abduction Adduction Rotation Supination

Pronation

Eversion Inversion

Description 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.) Straightening and extending a joint to increase the angle between two bones or two body parts Moving a body part away from the midline of the body Moving a body part toward the midline of the body Moving a body part around its axis Turning the palm of the hand anteriorly or upward. (Note: Here, lying on the back refers to the back of the hand.) Turning the palm of the hand posteriorly or downward. (Note: Here, face down refers to the face of the palm.) Turning a body part outward and toward the side Turning a body part inward

Muscle Type Flexor

Extensor

Abductor Adductor Rotator Supinator

Pronator

Evertor Invertor

Muscles of the Head and Neck o o o o o o o o

Frontalis: Moves the eyebrows or wrinkles the forehead skin. Temporalis: Moves the mandible (lower jaw) upward and backward. Orbicularis oculi: Closes the eyelids or presses them together. Orbicularis oris: Closes the lips or presses them together. Masseter: Moves the mandible (lower jaw) upward. Buccinator: Moves the cheeks. Sternocleidomastoid: Bends the head toward the sternum (flexion) and turns the head to either side (rotation). Platysma: Moves the mandible (lower jaw) down

Muscles of the Shoulders, Back, and Chest o o o

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Deltoid: Raises the arm and moves the arm away from the body (abduction). Pectoralis major: Moves the arm anteriorly and medially across the chest (adduction). Intercostal muscles: Muscle pairs between the ribs; one contracts during inspiration to spread the ribs apart; the other contracts during forced expiration, coughing, or sneezing to pull the ribs together. Trapezius: Raises the shoulder, pulls the shoulder blades together, elevates the clavicle. Turns the head from side to side (rotation). Moves the head posteriorly (extension). Latissimus dorsi: Moves the arm posteriorly and medially toward the vertebral column (adduction).

Muscles of the Upper Extremity o o o o

Biceps brachii: Bends the upper arm toward the shoulder (flexion) and bends the lower arm toward the upper arm (flexion). Triceps brachii: Straightens the lower arm (extension). Brachioradialis: Bends the lower arm toward the upper arm (flexion). Thenar muscles: Bend the thumb (flexion) and move it toward the palm (adduction).

Muscles of the Abdomen o o o

External abdominal oblique: Bends the upper body forward (flexion), rotates the side of the body medially, and compresses the side of the abdominal wall. Internal abdominal oblique: Bends the upper body forward (flexion), rotates the side of the body medially, and compresses the side of the abdominal wall. Rectus abdominis: Bends the upper body forward (flexion) and compresses the anterior abdominal wall.

Muscles of the Lower Extremity

Anterior Leg: o o o o o

Rectus femoris: Bends the upper leg toward the abdomen (flexion); straightens the lower leg (extension). Sartorius: Bends the upper leg toward the abdomen (flexion) and rotates it laterally. Vastus lateralis and vastus medialis: Bend the upper leg toward the abdomen (flexion); straighten the lower leg (extension). Peroneus longus: Raises the lateral edge of the foot (eversion) and bends the foot downward (plantar flexion). Tibialis anterior: Bends the foot up toward the leg (dorsiflexion)

Quadriceps femoris is a collective name for the group of four muscles—the rectus femoris, vastus lateralis, vastus intermedius (beneath the vastus lateralis), and vastus medialis—on the anterior and lateral upper leg. The tendons of the four heads of these muscles join together and insert on the tibia. These muscles straighten the lower leg (extension). Posterior Leg: o o o o

Gluteus maximus: Moves the upper leg posteriorly (extension) and rotates it laterally. Biceps femoris: Moves the upper leg posteriorly (extension) and bends the lower leg toward the buttocks (flexion). Semitendinosus and semimembranosus: Move the upper leg posteriorly (extension), bend the lower leg toward the buttocks (flexion), and rotate the leg medially. Gastrocnemius: Bends the foot downward (plantar flexion) and lets you stand on tiptoe.

Hamstrings is a collective name for the group of three muscles—the biceps femoris, semitendinosus, and semimembranosus—on the posterior upper leg. These muscles move the upper leg posteriorly (extension) and bend the lower leg toward the buttocks (flexion).

Physiology of a Muscle Contraction A muscle is composed of several muscle fascicles, each of which is individually wrapped in fascia. Each muscle fascicle is a bundle of individual muscle fibers. These run parallel to each other so that, when they contract, they all pull in the same direction. A muscle fiber (which is actually one long muscle cell) has hundreds of nuclei along its length to speed up the chemical processes that occur as it contracts. Each muscle fiber is composed of myofibrils that contain thin strands of the protein actin and thick strands of the protein myosin that give skeletal muscle its characteristic striated (striped) appearance under a microscope. A muscle contracts in response to an electrical impulse from a nerve. On a microscopic level, each muscle fiber is connected to a single nerve cell at a neuromuscular junction. The nerve cell releases the neurotransmitter acetylcholine, a chemical messenger that changes the permeability of the muscle fiber and allows sodium ions to flow into it. This releases calcium ions from their storage site within the muscle fiber. Calcium causes the thin strands (actin) to slide between the thick strands (myosin), which shortens the muscle and produces a muscle contraction . The muscle eventually relaxes when acetylcholine is inactivated by an enzyme and the calcium ions are pumped back into their storage site.

Even when not actively moving, your muscles are in a state of mild, partial contraction because of nerve impulses from the brain and spinal cord. This produces muscle tone that keeps the muscles firm and ready to act. This is the only aspect of muscle activity that is not under conscious control.

Diseases Word or Phrase Atrophy

Avulsion

Compartment Syndrome

Contracture

Fibromyalgia

Description Loss of muscle bulk in one or more muscles. It is caused by a lack of use or by malnutrition, or it can occur in any part of the body that is paralyzed because the muscles receive no electrical impulses from the nerves. The muscle is atrophic. It is also known as muscle wasting. Treatment: Correct the underlying cause. Condition in which the muscle tears away from the tendon or the tendon tears away from the bone. Treatment: Surgical repair (myorrhaphy or tenorrhaphy) The result of a severe blunt or crushing injury that causes bleeding in the muscles of the leg. The fascia acts as a compartment, holding in the accumulating blood. The increased pressure causes muscle and nerve damage and tissue death. Treatment: Fasciotomy to allow the blood and fluid to drain out. Inactivity or paralysis coupled with continuing nerve impulses can cause an arm or leg muscle to become progressively flexed and drawn into a position where it becomes nearly immovable. Treatment: Range of motion (ROM) exercises and frequent repositioning. Pain located at specific, hyperirritable trigger points in the muscles of the neck, back, or hips. The trigger points are tender to the touch and feel firm. The cause is not known, but may be related to an overreaction to painful stimuli with a possible history of prior injury or a genetic predisposition. Fibromyalgia is associated with disturbed sleep patterns and sometimes depression. Treatment: Analgesic drug, muscle relaxant drug, massage, and trigger point injections with a local anesthetic drug.

Hyperextension-Hyperflexion Injury

Muscle Contusion

Muscle Spasm

Muscle Strain

Muscular Dystrophy

Myalgia

Myasthenia Gravis

Injury that occurs during a car accident as a person’s head snaps forward and then backward in response to the car’s changing speed. This causes a muscle strain or muscle tear, as well as damage to the nerves. It is also known as acceleration–deceleration injury or whiplash. Treatment: Soft cervical collar to support the neck, rest, analgesic drug, nonsteroidal antiinflammatory drug. Condition in which blunt trauma causes some bleeding in the muscle. It is also known as a bruise. Treatment: Analgesic drug. Painful but temporary condition with a sudden, severe, involuntary contraction of a muscle, often in the legs. It can be brought on by overexercise. It is also known as a muscle cramp. Torticollis is a painful spasm of the muscles on one side of the neck. It is also known as wryneck. Treatment: Massage, muscle relaxant drug, analgesic drug Overstretching of a muscle, often due to physical overexertion. This causes inflammation, pain, swelling, and bruising as capillaries in the muscle tear. It is also known as a pulled muscle. Treatment: Rest, analgesic drug, nonsteroidal anti-inflammatory drug. Genetic mutation of the gene that normally makes the muscle protein dystrophin. Without dystrophin, the muscles weaken and then atrophy. It begins in early childhood with weakness in the lower extremities and then the upper extremities. The most common and most severe form is Duchenne’s muscular dystrophy; Becker’s muscular dystrophy is a milder form. Weakness of the diaphragm with an inability to breathe is the most frequent cause of death. Treatment: Supportive care. Pain in a muscle due to injury or muscle disease. Polymyalgia is pain in several muscle groups. Treatment: Analgesic drug, massage. Autoimmune disorder with abnormal and rapid fatigue of the muscles, particularly in the muscles of the face, where there is ptosis (drooping) of the eyelids. The weakness worsens during the day, but is relieved by rest. The body produces antibodies against its own acetylcholine

Myopathy

Myositis

Repetitive Strain Injury

Rhabdomyoma Rhabdomyo-sarcoma

Rotator Cuff Tear

Movement Disorders

receptors on the muscle fibers. The antibodies destroy many of the receptors. There are normal levels of acetylcholine, but too few receptors remain to produce a sustained muscle contraction. Treatment: Thymectomy to remove the thymus because it contributes to the abnormal immune response; drug that prolongs the action of acetylcholine. Plasmapheresis to remove antibodies from the blood. Category that includes many different diseases of the muscles. Treatment: Correct the underlying cause. Inflammation of a muscle with localized swelling and tenderness. It can be caused by injury or strain. Polymyositis is a chronic, progressive disease that causes widespread inflammation of muscles with weakness and fatigue. The cause is unknown, although it may be an autoimmune disorder. Dermatomyositis causes a skin rash as well as muscle weakness and inflammation. Treatment: Analgesic drug, nonsteroidal antiinflammatory drug, corticosteroid drug. Condition affecting the muscles, tendons, and sometimes the nerves. It occurs as a result of trauma caused by repetitive movements over an extended period of time. It includes tennis elbow, carpal tunnel syndrome, and other disorders. It is also known as cumulative trauma disorder (CTD). Treatment: Rest, analgesic drug, nonsteroidal anti-inflammatory drug. Benign tumor in a muscle. Treatment: Surgical removal. Cancerous tumor in a muscle. This cancer usually occurs in children and young adults. Treatment: Surgical removal, chemotherapy drugs, and radiation therapy. Tear in the rotator muscles of the shoulder that surround the head of the humerus. These muscles help to abduct the arm. The tear can be caused by acute trauma or repetitive overuse, particularly motions in which the arm is above the head. Treatment: Surgical repair

Word or Phrase Ataxia

Bradykinesia

Dyskinesia

Hyperkinesis

Restless Legs Syndrome (RLS)

Tremor

Diseases of the Bursa, Fascia, or Tendon

Description Incoordination of the muscles during movement, particularly incoordination of the gait. It is caused by disease of the brain or spinal cord, cerebral palsy, or an adverse reaction to a drug. The patient is ataxic. Treatment: Correct the underlying cause. Leg braces or crutches, if needed. Abnormally slow muscle movements or a decrease in the number of spontaneous muscle movements. It is usually associated with Parkinson’s disease, a neurologic disease of the brain. Treatment: Drug for Parkinson’s disease. Abnormal motions that occur because of difficulty controlling the voluntary muscles. Attempts at movement become tics, muscle spasms, muscle jerking (myoclonus ), or slow, wandering, purposeless writhing of the hand (athetoid movements) in which some muscles of the fingers are flexed and others are extended. It is associated with neurologic disorders (Parkinson’s disease, Huntington’s chorea, cerebral palsy, etc.). Treatment: Correct the underlying cause An abnormally increased amount of muscle movements. Restlessness. It can be a side effect of a drug. Treatment: Correct the underlying cause. An uncomfortable restlessness and twitching of the muscles of the legs, particularly the calf muscles, along with an indescribable tingling, aching, or crawling-insect sensation. This usually occurs at night and can interfere with sleep. The exact cause is unknown. Treatment: The drug Requip, which stimulates dopamine receptors in the brain. Tranquilizer drug may be of some help Small, involuntary, sometimes jerky, back-andforth movements of the hands, head, jaw, or extremities. These are continuous and cannot be controlled by the patient. These are usually due to essential familial tremor, an inherited condition. Treatment: Beta-blocker drug.

Word or Phrase Bursitis

Dupuytren’s Contracture

Fasciitis

Ganglion

Lateral Epicondylitis

Medial Epicondylitis

Description Inflammation of the bursal sac because of repetitive muscle contractions or pressure on the bone underneath the bursa. It can occur with any joint that has a bursa, but most often occurs in the should...