anatomy ch 6 list 2

flexion

a movement that decreases and angle of the joint and brings two bones closer; usually along the sagittal plane; ex. pulling your forearm closer to you

extension

a movement that increases the angle between two bones and moves two bones further apart; ex. extending your forearm

rotation

the movement of a bone around its longitudinal axis; ex. shaking your head “no”

abduction

moving a limb away from the midline; ex. holding your arm away from your body

adduction

moving a limb toward the midline; ex. moving your arm towards your body

circumduction

a combination of flexion, extension, abduction, adduction; the proximal end of the limb stays stationary while the distal end of the limb moves in a circle

origin

attachment points of the muscle to the immovable or less movable bone

insertion

attachment point of the muscle to the movable bone; the bone that the muscle will move by contracting

dorsiflection

lifting the superior surface of the foot towards your shin; standing on your heels

plantar flexion

depressing the foot; pointing your toes

inversion

to turn the sole of the foot medially; to stand on the outside edge of the sole of your foot

eversion

to turn the sole of the foot laterally; to stand on the inside edge of the sole of your foot

supination

when the forearm rotates laterally; palms face anteriorly; the radius and ulna are parallel

pronation

when the forearm rotates medially; the palms face posteriorly; the radius and ulna form an X

opposition

when you move your thumb to touch the tips of your other fingers

prime mover

the muscle that has the major responsibility for causing a particular movement; ex. your bicep when you move your forearm closer to your humerus

antagonist

muscles that oppose/reverse a movement; ex. your triceps when you move your forearm closer to your humerus

synergist

help prime movers by producing the same movement or by reducing undesirable movements; ex. when you make a fist, these muscles stabilize the wrist so the prime mover can act on the finger joints

fixators

specialized synergists that hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the intended bone; ex. the muscles that anchor the scapulae to the thorax

circular

the arrangement of fascicles in concentric rings; also called sphinctors; ex. the orbicularis muscles around the eyes

convergent 

the arrangement of fascicles towards a single insertion tendon; generally triangle shaped; ex. pectoralis major

parallel

the arrangement of fascicles where the length of the fascicles run along the long axis of the muscle; straplike; ex. the sartorius muscle in the anterior leg

fusiform

a modification of the parallel arrangement that results in a spindle-shaped muscle with an expanded midsection; ex. biceps brachii of the arm

pennate

fascicle pattern where short fascicles attach laterally to a central tendon; looks like a feather; ex. the rectus femoris muscle of the leg

torticollis

a condition where the head is involuntarily twisted or tilted to one side; often caused by an injury to the sternocleidomastiod muscle, which results in spasms; “wryneck”