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
2
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
3
Types of Muscles
• Cardiac
– Forms the wall of the heart
– Involuntary
4
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
5
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
6
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
7
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
8
Muscles of
the Upper Extremities
• 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
9
Muscles of
the Upper Extremities
• Pectoralis Major
– Large, fan-shaped muscle
– Crosses the upper part of the front chest
– Originates from sternum
• Crosses over to humerus
10
Muscles of
the Upper Extremities
• Deltoid
– Covers the shoulder joint
– Originates from clavicle and scapula
• Inserts on lateral side of the humerus
11
Muscles of
the Upper Extremities
• Biceps Brachii
– Muscle has two heads
– Originates from scapula
• Inserts on the radius
12
Muscles of
the Upper Extremities
• Triceps Brachii
– Muscle has three heads
– Originates from scapula and humerus
– Inserts onto olecranon process of the ulna
• At the elbow
13
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
14
Muscles of
the Lower Extremities
• Quadriceps Femoris
– Forms 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
15
Muscles of
the Lower Extremities
• 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
16
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
18
Polymyositis
• Pronounced
– (pol-ee-my-oh-SIGH-tis)
• Defined
– Chronic, progressive disease affecting the
skeletal muscles
– Characterized by muscle weakness and
degeneration
– Atrophy
19
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
20
Rotator Cuff Tear
21
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
23
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
24
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
25
Classification of Joints
(Structural)
26
Classification of Joints
(Structural)
• Cartilaginous
– Bones are connected by cartilage
– Limited movement joint
• Example: Symphysis
– Joint between the pubic bones of the pelvis
27
Classification of Joints
(Structural)
28
Classification of Joints
(Structural)
• 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
29
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
30
Classification of Joints
(Functional)
31
Movements of Joints
• Flexion
– Bending motion
– Decreases angle between two bones
• Extension
– Straightening motion
– Increases angle between two bones
32
Movements of Joints
• Abduction
– Movement of a bone away from midline of the
body
• Adduction
– Movement of a bone toward midline of the
body
33
Movements of Joints
• Supination
– Act of turning the palm up or forward
• Pronation
– Act of turning the palm down or backward
34
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
35
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
36
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
37
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”
39
Arthritis
• Pronounced
– (ar-THRY- tis)
• Defined
– Inflammation of joints
40
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
41
Bunion (Hallux Valgus)
• Pronounced
– (BUN-yun) (HAL-uks VAL-gus)
• Defined
– Abnormal enlargement of the joint at the base
of the great toe
42
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
43
Ganglion
• Pronounced
– (GANG-lee-on)
• Defined
– Cystic tumor developing on a tendon
– Sometimes occurs on back of wrist
44
Gout
• Pronounced
– (GOWT)
• Defined
– Acute arthritis that is characterized by
inflammation of the first metatarsal joint of the
great toe
45
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
46
Herniated Disk
47
Lyme Disease
• Pronounced
– (LYME dih-ZEEZ)
• Defined
– Acute, recurrent inflammatory infection,
transmitted through the bite of an infected
deer tick
48
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
49
Osteoarthritis
50
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
51
Sprains
• Pronounced
– (SPRAYN)
• Defined
– Injury involving ligaments that surround and
support a joint
• Caused by a wrenching or twisting motion
52
Systemic Lupus Erythematosus
• Pronounced
– (sis-TEM-ic LOO-pus er-ih-them-ah-TOHsis)
• Defined
– Chronic, inflammatory connective tissue
disease affecting the skin, joints, nervous
system, kidneys, lungs, and other organs
– Characteristic “butterfly rash” appears on the
face
53
DIAGNOSTIC
TECHNIQUES, TREATMENTS
AND PROCEDURES
Joints
Diagnostic Techniques,
Treatments, and Procedures
• 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
55
Diagnostic Techniques,
Treatments, and Procedures
• Arthroplasty
– Surgical repair of a joint
• Arthroscopy
– Visualization of the interior of a joint using an
endoscope
56
Diagnostic Techniques,
Treatments, and Procedures
• 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
57
Diagnostic Techniques,
Treatments, and Procedures
• Rheumatoid factor
– Blood test that measures the presence of
unusual antibodies that develop in a number
of connective tissue diseases, such as
rheumatoid arthritis
58