13 gross anatomy

Prime Mover (Agonist)

Muscles that are most responsible for producing a particular movement.

Antagonist

Muscles that oppose or reverse a movement.

Synergist

Muscles that aid the action of agonists either by assisting with the same movement or by reducing undesirable or unnecessary movement.

Fixators

Specialized synergists that immobilize the origin of a prime mover so that all the tension is exerted at the insertion.

Rectus Muscle

A muscle with fibers running parallel to an imaginary line or the midline of the body.

Transverse Muscle

A muscle with fibers running at right angles to an imaginary line or the midline of the body.

Oblique Muscle

A muscle with fibers running diagonally to an imaginary line or the midline of the body.

Maximus

Term used to describe the largest muscle in a group.

Minimus

Term used to describe the smallest muscle in a group.

Longus

Term used for a muscle that is long in comparison to others.

Brevis

Term used for a muscle that is short in comparison to others.

Biceps

A muscle with two origins.

Triceps

A muscle with three origins.

Quadriceps

A muscle with four origins.

Deltoid Muscle

A muscle that resembles a triangle.

Zygomaticus

A muscle used in smiling.

Orbicularis Oris

Muscle around the mouth used for closing and puckering lips.

Rectus Abdominis

The straight muscle of the abdomen.

Sternocleidomastoid

Muscle that has its origin on the sternum and clavicle.

Erector Spinae

A group of muscles responsible for extending the vertebral column.

Gastrocnemius

A superficial muscle of the calf that plantar flexes the foot.

Flexor Digitorum Longus

A deep muscle that flexes the toes.

Tibialis Anterior

A muscle that dorsiflexes and inverts the foot.

Latissimus Dorsi

A large muscle on the back that extends the arm.

Pectoralis Major

A prime mover of arm flexion.

Trapezius

A muscle that stabilizes, raises, retracts, and rotates the scapula.

Extensor Digitorum

A muscle that extends the toes.

Biceps Brachii

A muscle that flexes and supinates the forearm.

Triceps Brachii

A powerful forearm extensor.

Iliopsoas

A powerful hip flexor.

Adductor Muscles

A group of muscles responsible for adducting the thigh.