Semispinalis capitis muscle

The semispinalis capitis is a distinct mass of the semispinalis thoracis and cervicis. It arises between the spinalis thoracis and the longissiums thoracis, and is divided into two parts:

• The biventer cervicis muscle: the dorsomedial division of semispinalis capitis that originates from the thoracolumbar fascia or thoracic vertebral transverse processes, courses superficial to mutifidi muscles to insert on occipital bone.
• The complexus muscle: the ventrolateral division of semispinalis capitis that arises from cervical vertebral articular processes and inserts lateral to the biventercervicis on occipital bone.

Origin: First five thoracic vertebrae and last cervical vertebrae.

Insertion: Occipital ridge.

Action: Raises the head and neck and in unilateral action to flex the head and neck laterally.

Nerve: Dorsal branches of the cervicales.