Key Terms
abduction
moving a body part away from the midline
contracture
a severe tightening of a flexor muscle resulting in bending of a joint. Foot drop is a common contracture,
extension
increasing the angle between two bones, or straightening a body part
muscle tone
occur in severe illness such as paralysis. When muscles are not used for a long period
rotation
turning a body part around its own axis;
adduction
moving a body part toward the midline
dorsiflexion
bending backward or bending the foot toward the knee
fascia
Other muscles attach by fascia, a tough, sheetlike membrane that covers and protects the tissue.
muscular system
More than 600 muscles make up the system known as the muscular system.
skeletal muscle
Skeletal muscle is attached to bones and causes body movement
cardiac muscle
they function without conscious thought or control.
elasticity
allows the muscle to return to its original shape after it has contracted or stretched
flexion
decreasing the angle between two bones, or bending a body part
origin
the origin of the shoulder muscle, called the deltoid, is by the clavicle and scapula. Its insertion is on the humerus. When the deltoid contracts, the area by the scapula
supination
turning a body part upward
circumduction
moving in a circle at a joint, or moving one end of a body part in a circle while the other end remains stationary, such as swinging an arm
excitability
irritability, the ability to respond to a stimulus such as a nerve impulse
insertion
is on the humerus. When the deltoid contracts, the area by the scapula
plantar flexion
bending forward or bending the foot away from the knee
tendons
which are strong, tough, fibrous
contractibility
muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement
extensibility
the ability to be stretched
involuntary
they function without conscious thought or control. Skeletal muscle is attached to bones and causes body movement.
pronation
turning a body part downward Supination: turning a body part upward
visceral muscle
are involuntary, meaning they function without conscious thought or control.