Muscles and Joints
CHAPTER 7
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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
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• 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
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• Cardiac – Forms the wall of the heart– Involuntary
Types of Muscles
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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
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• 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
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• Sternomastoid• Also called the sternocleidomastoid
– Extends from the sternum upward along the side of the neck to the mastoid process
Muscles of the Head and Neck
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• Trapezius– Triangular-shaped muscle – Extends across the back of the shoulder– Covers back of neck– Inserts on clavicle and scapula
Muscles of the Upper Extremities
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• 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
Muscles of the Upper Extremities
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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
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Muscles of the Upper Extremities
• Deltoid – Covers the shoulder joint– Originates from clavicle and scapula
• Inserts on lateral side of the humerus
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Muscles of the Upper Extremities
• Biceps Brachii– Muscle has two heads– Originates from scapula
• Inserts on the radius
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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
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• 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
Muscles of the Lower Extremities
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• 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
Muscles of the Lower Extremities
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• 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
Muscles of the Lower Extremities
PATHOLOGICAL CONDITIONS
Muscles
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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
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Polymyositis
• Pronounced– (pol-ee-my-oh-SIGH-tis)
• Defined– Chronic, progressive disease affecting the
skeletal muscles– Characterized by muscle weakness and
degeneration – Atrophy
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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
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Rotator Cuff Tear
DIAGNOSTIC TECHNIQUES, TREATMENTS,
AND PROCEDURES
Muscles
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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
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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
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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
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Classification of Joints(Structural)
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Classification of Joints(Structural)
• Cartilaginous – Bones are connected by cartilage– Limited movement joint
• Example: Symphysis– Joint between the pubic bones of the pelvis
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Classification of Joints(Structural)
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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
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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
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Classification of Joints(Functional)
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Movements of Joints• Flexion
– Bending motion– Decreases angle between two bones
• Extension– Straightening motion– Increases angle between two bones
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Movements of Joints• Abduction
– Movement of a bone away from midline of the body
• Adduction– Movement of a bone toward midline of the
body
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Movements of Joints• Supination
– Act of turning the palm up or forward• Pronation
– Act of turning the palm down or backward
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• 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
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• 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
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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
PATHOLOGICAL CONDITIONS
Joints
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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”
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Arthritis• Pronounced
– (ar-THRY- tis)• Defined
– Inflammation of joints
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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
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Bunion (Hallux Valgus)• Pronounced
– (BUN-yun) (HAL-uks VAL-gus)• Defined
– Abnormal enlargement of the joint at the base of the great toe
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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
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Ganglion• Pronounced
– (GANG-lee-on)• Defined
– Cystic tumor developing on a tendon– Sometimes occurs on back of wrist
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Gout• Pronounced
– (GOWT)• Defined
– Acute arthritis that is characterized by inflammation of the first metatarsal joint of the great toe
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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
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Herniated Disk
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Lyme Disease• Pronounced
– (LYME dih-ZEEZ)• Defined
– Acute, recurrent inflammatory infection, transmitted through the bite of an infected deer tick
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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
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Osteoarthritis
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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
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Sprains• Pronounced
– (SPRAYN)• Defined
– Injury involving ligaments that surround and support a joint• Caused by a wrenching or twisting motion
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Systemic Lupus Erythematosus• Pronounced
– (sis-TEM-ic LOO-pus er-ih-them-ah-TOH-sis)
• Defined– Chronic, inflammatory connective tissue
disease affecting the skin, joints, nervous system, kidneys, lungs, and other organs
– Characteristic “butterfly rash” appears on the face
DIAGNOSTIC TECHNIQUES, TREATMENTS
AND PROCEDURES
Joints
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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
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Diagnostic Techniques, Treatments, and Procedures
• Arthroplasty– Surgical repair of a joint
• Arthroscopy– Visualization of the interior of a joint using an
endoscope
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• 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
Diagnostic Techniques, Treatments, and Procedures
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• Rheumatoid factor– Blood test that measures the presence of
unusual antibodies that develop in a number of connective tissue diseases, such as rheumatoid arthritis
Diagnostic Techniques, Treatments, and Procedures