Muscle Functions and Movements: Anatomy and Nomenclature

Extensor

Increases joint angle

Abductor

Moves bone away from midline

Adductor

Moves bone closer to midline

Supinator

Turns palm superiorly or anteriorly

Pronator

Turns palm inferiorly or posteriorly

Levator

Produces superior movement

Depressor

Produces inferior movement

Tensor

Makes a body part rigid

Sphincter

Decreases size of opening

Longus

Long

Longissimus

Longest

Teres

Long and round

Brevis

Short

Magnus

Large

Major

Larger

Maximus

Largest

Minor

Small

Minimus

Smallest

Vastus

Great

Extension

Increases the angle between articulating bones; usually in the sagittal plane

Hyperextension

Continuation of extension beyond anatomical position

Flexion

Decreases the angle between articulating bones; usually in the sagittal plane

Lateral Flexion

Movement of the torso in the frontal plane

Abduction

Movement of a bone away from the midline; usually in the frontal plane

Adduction

Movement of a bone toward the midline; usually in the frontal plane

Circumduction

Combination of flexion, abduction, extension, and adduction in succession

Elevation

Movement of a body part superiorly

Depression

Movement of a body part inferiorly

Supination

Forearm movement turning the palm anteriorly or superiorly

Pronation

Forearm movement turning the palm posteriorly or inferiorly

Inversion

Soles of the feet turn medially toward each other

Eversion

Soles of the feet turn laterally away from each other

Dorsiflexion

Bending the foot toward the dorsum (superior surface)

Plantar Flexion

Bending the foot toward the plantar surface (sole)

Protraction

Movement of a body part anteriorly; in the transverse plane

Retraction

Movement of a body part posteriorly; in the transverse plane

Opposition

Thumb moves across the palm to touch fingertips of the same hand

Rotation

Movement of a bone around its longitudinal axis

Agonist

Prime mover; performs most of the work in a movement

Antagonist

Opposes the action of the agonist

Synergist

Assists the agonist and helps stabilize movement