key terms
Abduction
Movement of a body part away from the midline of the body.
Contracture
A tightening or shortening of a muscle that results in limited movement of the joint.
Extension
Increasing the angle between two bones; straightening a body part.
Muscle tone
The slight, constant contraction of muscles that helps maintain posture.
Rotation
Movement of a body part around its long axis.
Adduction
Movement of a body part toward the midline of the body.
Dorsiflexion
Bending the foot upward at the ankle.
Fascia
Tough, sheet-like connective tissue that covers and protects muscles.
Muscular system
The body system made of muscles that allows movement, posture, and heat production.
Skeletal muscle
Muscle attached to bones; voluntary and responsible for body movement.
Cardiac muscle
Muscle tissue found only in the heart; it is involuntary and able to contract without conscious control.
Elasticity
The ability of a muscle to return to its original shape after being stretched or contracted.
Flexion
Decreasing the angle between two bones; bending a body part
Origin
The end of a muscle that attaches to a fixed or immovable bone.
Supination
Turning the palm or foot upward
Circumduction
A circular movement of a limb that combines flexion, extension, abduction, and adduction.
Excitability
The ability of a muscle to respond to a stimulus such as a nerve impulse.
Insertion
The end of a muscle that is attached to a movable bone.
Plantar flexion
Bending the foot downward, away from the leg.
Tendons
Strong, fibrous connective tissues that attach muscles to bones.
Contractibility
The ability of muscle fibers to shorten and produce movement when stimulated.
Extensibility
The ability of muscle fibers to stretch without being damaged.
Involuntary
Muscle action that cannot be consciously controlled.
Pronation
Turning the palm or foot downward.
Visceral muscle
Smooth, involuntary muscle found in organs such as the stomach and intestines.