Proximal Attachment
Longissimus cervicis is located medial to longissimus thoracis, it attaches by long thin tendons to the posterior surfaces of the transverse processes of T1 to T5.

Distal Attachment
It passes superiorly to the posterior tubercles of the transverse processes of C2 to C6.

Nerve Supply
Longissimus cervicis is supplied by the dorsal rami of C2 to T5.

Action
When working individually it produces lateral flexion and some extension of the neck.  When both sides are working they extend the neck.