chapter 7

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CHAPTER 7

Muscles and Joints


Muscles Overview

• Muscles support and maintain body posture through a low level of contraction

• Skeletal muscles produce a substantial amount of heat when they contract


Types of Muscles

• Skeletal – Attaches to the bones of the skeleton

– Voluntary/striated

– Operates under conscious control

• Smooth – Called visceral muscle

– Involuntary/not striated

– Not under conscious control


Types of Muscles

• Cardiac – Forms the wall of the heart

– Involuntary


Attachment of Muscles

• Tendon– Attaches muscles to bones

• Point of origin– Point of attachment of the muscle to the bone that is less

movable

• Point of insertion– Point of attachment to the bone that it moves


Attachment of Muscles


Question

True or False: Of the 3 types of muscle, cardiac is the only one that is voluntary.


Muscles of the Head and Neck

• Buccinator– Located in fleshy part of cheek

• Temporal– Located above and near the ear

• Masseter– Located at the angle of the jaw

– Raises the mandible and closes the jaw


Muscles of the Head and Neck

• Sternomastoid– Also called the sternocleidomastoid

– Extends from the sternum upward along the side of the neck to the mastoid process


Muscles of the Upper Extremities

• Trapezius– Triangular-shaped muscle

– Extends across the back of the shoulder

– Covers back of neck

– Inserts on clavicle and scapula



• Latissimus dorsi– Originates from vertebrae of lower back

– Crosses lower half of thoracic region

– Passes between humerus and scapula

– Inserts on anterior surface of humerus

– Forms the posterior border of the armpit



• Pectoralis major– Large, fan-shaped muscle

– Crosses the upper part of the front chest

– Originates from sternum

– Crosses over to humerus



• Deltoid – Covers the shoulder joint

– Originates from clavicle and scapula

– Inserts on lateral side of the humerus



• Biceps brachii– Muscle has two heads

– Originates from scapula

– Inserts on the radius



• Triceps brachii– Muscle has three heads

– Originates from scapula and humerus

– Inserts onto olecranon process of the ulna at the elbow


Question

If you have a tension headache and the back of your neck feels like it is in a vice grip, which muscle is most likely responsible?a. trapezius

b. sternocleidomastoid

c. biceps brachii

d. latissimus dorsi


Muscles of the Lower Extremities

• Gluteus maximus– Forms most of the fleshy part of the buttock

– Originates from ilium and inserts in the femur

• Gluteus medius– Located above the upper outer quadrant of the gluteus

maximus muscle

– Originates from posterior part of ilium

– Inserts in greater trochanter of the femur



• Quadriceps femoris– Form anterior part of the thigh

– Help extend the thigh

• Hamstring muscles– Located in posterior part of the thigh

– Help flex leg on the thigh

– Help extend the thigh



• Gastrocnemius– Main muscle of the calf

– Attaches to heel bone by way of Achilles tendon

– Used to plantar flex foot and flex toes

• Tibialis anterior– Positioned on the front of the leg

– Used to dorsiflex foot and turn foot inward


Question

A runner suddenly grabs the back of his or her leg in pain. Which muscle group was injured?a. quadriceps femoris

b. gastrocnemius

c. hamstring

d. tibialis anterior


PATHOLOGICAL CONDITIONS

Muscles


Muscular Dystrophy

• Pronounced– (MUSS-kew-lar DIS-troh-fee)

• Defined– Group of genetically transmitted disorders

– Characterized by progressive weakness and muscle fiber degeneration

– No evidence of nerve involvement or degeneration of nerve tissue


Polymyositis

• Pronounced– (pol-ee-my-oh-SIGH-tis)

• Defined– Chronic, progressive disease affecting the skeletal

muscles

– Characterized by muscle weakness and degeneration

– Atrophy


Rotator Cuff Tear

• Pronounced– (ROH-tay-tor kuff TAIR)

• Defined– Tear in muscles that form a “cuff” over upper end of arm

• Rotator cuff helps to lift and rotate the arm

• Also helps to hold head of humerus in place during abduction of arm


Rotator Cuff Tear


Question

True or False: The term muscular dystrophy means development of bad muscle, while polymyositis means inflammation of many muscles.


DIAGNOSTIC TECHNIQUES, TREATMENTS, AND PROCEDURES

Muscles


Diagnostic Techniques, Treatments, and Procedures

• Electromyography– Process of recording strength of contraction of a muscle

when stimulated by electric current

• Muscle biopsy– Extraction of a specimen of muscle tissue, through

biopsy needle or incisional biopsy, for purpose of examining it under a microscope


ANATOMY & PHYSIOLOGY

Joints


Joints Overview

• Joint = articulation– Point at which two individual bones connect

– Joints determine degree of movement

– Movement ranges from free to limited

• Suture = immovable joint– Purpose is to bind bones together


Classification of Joints (Structural)

• Fibrous – Surfaces of bone fit closely together

– Held together by fibrous connective tissue

– Immovable joint• Example: suture between the skull bones



• Cartilaginous – Bones are connected by cartilage

– Limited movement joint• Example: Symphysis

– Joint between the pubic bones of the pelvis



• Synovial – Space between the bones = joint cavity

– Joint cavity lined with synovial membrane

– Synovial membrane secretes synovial fluid

– Bones are held together by ligaments

– Free movement joint• Example = shoulder


Classification of Joints (Functional)

• Hinge – Allows a back and forth type motion

• Example: elbow

• Ball-and-socket – Allows movement in many directions around a central

point• Example: shoulder joint and hip joint


Classification of Joints (Functional)


Question

True or False: The cartilaginous joint between the 2 halves of the pelvis (symphysis) is vital for childbirth.


Question

What enables our movable joints to move freely and without pain?a. cartilage

b. fibrous tissue

c. connective tissue

d. synovial membrane


Movements of Joints

• Flexion– Bending motion

– Decreases angle between two bones

• Extension– Straightening motion

– Increases angle between two bones


Movements of Joints

• Abduction– Movement of a bone away from midline of the body

• Adduction– Movement of a bone toward midline of the body


Movements of Joints

• Supination– Act of turning the palm up or forward

• Pronation– Act of turning the palm down or backward


Movements of Joints

• Dorsiflexion– Narrows the angle between the leg and the top of the

foot

– Foot is bent backward, or upward, at the ankle


Movements of Joints

• Plantar flexion– Increases angle between the leg and the top of the foot

– Foot is bent downward at the ankle

– Toes pointing downward, as in ballet dancing


Movements of Joints

• Rotation– Turning of a bone on its own axis

• Circumduction– Movement of an extremity around in a circular motion

– Can be performed with ball-and-socket joints


Question

When bodybuilders are showing off their muscles, what movement are they using?a. extension

b. flexion

c. abduction

d. circumduction


Question

True or False: When I turn my head, I am rotating vertebrae in my neck.


PATHOLOGICAL CONDITIONS

Joints


Adhesive Capsulitis

• Pronounced– (add-HE-sive cap-sool-EYE-tis)

• Defined– Shoulder condition characterized by a stiffness of the

shoulder, limited shoulder movement, and pain

– Also known as “frozen shoulder”


Arthritis

• Pronounced– (ar-THRY-tis)

• Defined– Inflammation of joints


Ankylosing Spondylitis

• Pronounced– (ang-kih-LOH-sing spon-dil-EYE-tis)

• Defined– Type of arthritis that affects the vertebral column

– Causes deformities of the spine


Bunion (Hallux Valgus)

• Pronounced– (BUN-yun) (HAL-uks VAL-gus)

• Defined– Abnormal enlargement of the joint at the base of the

great toe


Bunion (Hallux Valgus)


Question

The treatment for bunions is surgical removal of the bony overgrowth. If -ectomy is the element for surgical removal, what is the correct term?a. buniectomy

b. bonyectomy

c. bunionectomy

d. ectomy


Dislocation

• Pronounced– (diss-loh-KAY-shun)

• Defined– Displacement of a bone from its normal location within a

joint

– Causes loss of function of the joint


Ganglion

• Pronounced– (GANG-lee-on)

• Defined– Cystic tumor developing on a tendon

– Sometimes occurs on back of wrist


Gout

• Pronounced– (GOWT)

• Defined– Acute arthritis that is characterized by inflammation of

the first metatarsal joint of the great toe


Herniated Disk

• Pronounced– (HER-nee-ay-ted disk)

• Defined– Rupture of the central portion of the vertebral disk

through the disk wall and into the spinal canal

– Also called a ruptured disk or a slipped disk


Herniated Disk


Lyme Disease

• Pronounced– (LYME dih-ZEEZ)

• Defined– Acute, recurrent inflammatory infection, transmitted

through the bite of an infected deer tick


Question

True or False: A herniated disk is referring to one of the cushions between the vertebral bodies. If inter- means between, the term to describe it must be interdiskal.


Osteoarthritis

• Pronounced– (oss-tee-oh-ar-THRY-tis)

• Defined– Most common form of arthritis

– Results from wear and tear on the joints, especially weight-bearing joints such as hips and knees

– Also known as degenerative joint disease


Osteoarthritis


Rheumatoid Arthritis

• Pronounced– (ROO-mah-toyd ar-THRY-tis)

• Defined– Chronic, systemic, inflammatory disease that affects

multiple joints of the body

– Mainly the small peripheral joints


Sprain

• Pronounced– (SPRAYN)

• Defined– Injury involving ligaments that surround and support a

joint

– Caused by a wrenching or twisting motion


Systemic Lupus Erythematosus

• Pronounced– (sis-TEM-ic LOO-pus er-ih-them-ah-TOH-sus)

• Defined– Chronic, inflammatory connective tissue disease

affecting the skin, joints, nervous system, kidneys, lungs, and other organs

– Characteristic “butterfly rash” appears on the face


Question

True or False: The most common form of arthritis is bony arthritis, also known as osteoarthritis.


DIAGNOSTIC TECHNIQUES, TREATMENTS, AND PROCEDURES

Joints



• Arthrocentesis– Surgical puncture of a joint with a needle for the purpose

of withdrawing fluid for analysis

• Arthrography– Process of X-raying the inside of a joint, after injecting

the joint with a contrast medium



• Arthroplasty– Surgical repair of a joint

• Arthroscopy– Visualization of the interior of a joint using an

endoscope



• Erythrocyte sedimentation (sed) rate– Blood test that measures the rate at which erythrocytes

settle to the bottom of a test tube filled with unclotted blood



• Rheumatoid factor– Blood test that measures the presence of unusual

antibodies that develop in a number of connective tissue diseases, such as rheumatoid arthritis


Question

An MRI of the knee shows a possible meniscus tear. The doctor opts to look right into the joint with a scope. This is called an _________.a. arthrotomy

b. arthrostomy

c. arthroplasty

d. arthroscopy

chapter 7

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