Proximal Attachment
Semispinalis capitis arises from a series of tendons from the tips of the transverse processes of C7 to T6/T7, the articular processes of C4 to C6 and occasionally the spinous process of C7 or T1.

Distal Attachment
The tendon forms a broad muscle, which passes superiorly to attach to the medial part of the occipital bone between the superior and inferior nuchal lines.  The medial part of the muscle is traversed by an incomplete tendinous intersection and may be separate, in which case it is known as spinalis capitis.

Nerve Supply
It is supplied by the dorsal rami of C4 to T6.

Action
Semispinalis capitis extends the head on the neck when both sides are working together and turns the face towards the opposite side when working individually.