Muscles of the Head and Abdomen

Occipitofrontalis

Frontal belly and Occipital belly

Frontal belly function

Draws scalp anteriorly, raises eyebrows, and wrinkles skin on forehead

Occipital belly

Draws scalp posteriorly (pulls the scalp backward)

Orbicularis oculi function

Closes eye

Orbicularis oculi location

Medial wall of orbit

Occipital belly location

occipital bone and mastoid process of temporal bone

Frontal belly location

Epicranial aponeurosis

Orbicularis oris function

Closes and protrudes lips, compresses lips against teeth; and shapes lips during speech

Masseter function

Elevates mandible (closing the mouth)

Orbicularis oris location

Muscle fibers surrounding opening of mouth

Masseter location

Mandible

Platysma function

Draws outer part of lower lip inferiorly and posteriorly (pouting), depresses mandible

Temporalis function

Elevates and retracts mandible

Sternocleidomastoid function

Act together to flex cervical portion of vertebral column (side to side movement, extension of head)

External oblique function

Acts with internal oblique to compress the abdomen and twist the vertebral column (rotates the opposite side)

Internal oblique function

Acts with external oblique to compress the abdomen and twist the vertebral column (rotates the same side)

Rectus abdominis function

Flexes vertebral column, pelvis, and compresses abdomen to aid in defecation, urination, childbirth, etc.

Transversus abdominis function

Compresses abdomen, act as spinal stabilization

Diaphragm function

Contraction/relaxation of diaphragm (inhalation and exhalation)