Human Muscular System Anatomy

Comprehensive vocabulary flashcards covering the major skeletal muscles and muscular landmarks across the head, neck, trunk, upper extremity, and lower extremity.

Occipitofrontalis (frontal belly)

The anterior muscle belly of the occipitofrontalis situated over the forehead that elevates the eyebrows and horizontally wrinkles the forehead skin.

Orbicularis oculi

The circular sphincter muscle that surrounds the eye socket, responsible for closing the eyelids, blinking, and squinting.

Orbicularis oris

The multi-layered circular muscle encircling the mouth that closes, protrudes, and compresses the lips.

Masseter

A powerful muscle of mastication that spans from the zygomatic arch to the ramus of the mandible, functioning primarily to elevate the mandible during chewing.

Buccinator

The principal deep muscle of the cheek that compresses the cheek against the teeth to prevent food pooling during chewing and assists in blowing.

Mentalis

A small paired muscle located on the chin that elevates and protracts the lower lip while wrinkling the skin of the chin.

Zygomaticus major

A facial muscle running from the zygomatic bone to the angle of the mouth that draws the angle upward and laterally during smiling.

Platysma

A superficial, thin sheet of muscle in the anterolateral neck that tenses the skin of the neck and pulls down the lower lip and corner of the mouth.

Sternocleidomastoid

A paired, two-headed neck muscle arising from the sternum and clavicle to insert onto the mastoid process, responsible for flexure and unilateral rotation of the head.

Epicranial aponeurosis

A fibrous, sheet-like tendon covering the vertex of the skull that connects the frontal and occipital bellies of the occipitofrontalis.

Pectoralis major

A large fan-shaped anterior thoracic wall muscle that functions to adduct, internally rotate, and flex the humerus at the shoulder joint.

Trapezius

A large, triangular superficial muscle of the upper back and posterior neck that elevates, retracts, and stabilizes the scapula.

Diaphragm

A broad, dome-shaped internal muscle separating the thoracic cavity from the abdominal cavity, functioning as the chief muscle of respiration.

Serratus anterior

A serrated muscle spanning from the upper eight ribs to the medial border of the scapula that protracts the scapula and holds it against the thoracic wall.

Rectus abdominis

A paired vertical muscle along the anterior abdominal wall segmented by tendinous intersections that flexes the lumbar spine and compresses abdominal contents.

External oblique

The outermost lateral abdominal muscle whose inferomedially angled fibers compress abdominal viscera and participate in trunk flexion and rotation.

Linea alba

A dense fibrous line running vertically along the midline of the anterior abdominal wall between the paired rectus abdominis muscles.

Latissimus dorsi

A broad, triangular muscle covering the lower posterior back that acts to extend, adduct, and medially rotate the humerus.

Deltoid

A thick, triangular multipennate muscle capping the shoulder joint that mediates arm abduction, flexion, and extension.

Biceps brachii

A two-headed muscle occupying the anterior compartment of the arm that serves as a powerful forearm supinator and elbow flexor.

Triceps brachii

A three-headed muscle situated in the posterior compartment of the arm that functions as the principal extensor of the elbow.

Brachioradialis

A superficial muscle on the radial side of the forearm that flexes the forearm at the elbow, particularly when the limb is mid-pronated.

Sartorius

A long, ribbon-like muscle traversing obliquely from the ASIS to the medial proximal tibia, facilitating hip flexion, abduction, and lateral rotation alongside knee flexion.

Rectus femoris

The central superficial muscle of the quadriceps femoris group, originating from the ilium to extend the knee and assist in flexing the hip.

Gluteus maximus

The large, heavy muscle constituting the bulk of the buttock, functioning as the primary extensor and lateral rotator of the thigh at the hip joint.

Biceps femoris

The lateral component of the hamstring group located in the posterior thigh that functions to flex the knee and extend the hip.

Semitendinosus

A medial hamstring muscle noted for its remarkably elongated distally positioned tendon that flexes the knee and extends the hip.

Tibialis anterior

A superficial muscle of the anterior compartment of the lower leg extending adjacent to the tibia that dorsiflexes and inverts the foot.

Gastrocnemius

A superficial two-headed calf muscle that plantarflexes the foot at the ankle and aids in flexion of the leg at the knee joint.

Soleus

A broad, flat posterior calf muscle positioned deep to the gastrocnemius that acts as a strong plantarflexor of the ankle.