Types of Muscle Movements Produced by Skeletal Muscle Contraction Shapes of bones, type of joint, dictates movement in several or 2 directions Flexion Abduction Extension Adduction Dorsiflecion Rotation Plantar Flexion Supination Pronation

FLEXION Movement that makes > between bones at their joints smaller than it was to start EXTENSION Actions opposite/antagonistic to flexions. Movement that makes the > between bones at their joints larger. Straightening and stretching.

DORSIFLEXION Movement that elevates top (dorsum) of foot & tilts it up. Stand on heels PLANTAR FLEXION Movement that directs bottom of foot downward. Stand on toes

ABDUCTION Moving body part away from midline (what muscles are involved?) ADDUCTION Moving body part to midline (What muscles are involved?)

ROTATION Moving around a longitudinal axis SUPINATION Palm of hand turned to anterior position (anatomical) PRONATION Palm of hand turned to posterior position

Specific Facts about Key Muscle Groups Flexors: muscles that flex (make angle between 2 bones smaller) produce walking, sitting, swimming, typing movements. Extensors: Also function in above movements but most important in maintaining posture (tonic contraction). Muscles move bones and the bones they move are their insertion bones.

MUSCLE DISORDERS Affect many body systems

Muscular Dystrophy: long lasting progressive disease of wasting and weakening of muscles.

Paralysis: muscles ok, brain/spinal cord message can’t activate muscles

Muscle Atrophy: muscles decrease in size from non use (ex. w/ cast, bedridden, paralysis)

Muscle Hypertrophy: Increase of muscle mass due to increased use/exercise Additional contractile proteins appear to be incorporated into existing myofibrils (chains of sarcomeres within a muscle cell). Limit to how large a myofibril can become: at some point, they split. These events appear to occur within each muscle fiber. Hypertrophy results from the growth of each muscle cell, not an increase in the # of cells.

Myasthenia Gravis: ?cause may involve defect in body’s immune system and lack of communication between nerves & muscles. Progressive muscle weakness  paralysis  death due to paralysis of respiratory muscles Commonly affects muscles that control eye and eyelid movement. 1st symptoms noticed may be eyelid drooping and/or blurred or doubled vision. Starts with ocular myasthenia, majority will develop weakness in other muscle groups within 1-2 yrs.

Though anyone can develop myasthenia gravis, those most likely to do so are women between age 20 and 40 or men between 50 and 70. Difficult for you to chew, swallow, smile, shrug, lift your arm up, grip, rise to a stand, or walk up stairs. When the muscles necessary for breathing are affected, a patient is said to be in myasthenic crisis. This is a life-threatening situation.

INTRAMUSCULAR INJECTIONS Injection < 5ml  Deltoid (2 fingers below acromion process & lateral to tip of acromion Injection > 5ml  Gluteal area (into gluteal medius near center of upper-outer quadrant, avoiding sciatic nerve and gluteal blood vessels).