Muscle · Neck

Semispinalis capitis

Musculus semispinalis capitis

The thick fleshy column either side of the midline at the back of the neck — most of what you feel when you grip the back of your own neck is this muscle, lying under the trapezius and splenius. It climbs from the transverse processes of the upper thoracic and lower cervical vertebrae to a broad attachment on the back of the skull between the two nuchal lines, and it is the principal extensor of the head: it holds the skull up against gravity all day and pulls it back when you look up. Two details make it clinically interesting. It attaches to the skull rather than to a vertebra, so it acts on the head as one piece; and the greater occipital nerve — the sensory nerve of the back of the scalp — pierces its tendon close to the skull on its way out, so the nerve to the scalp passes through the substance of a working muscle rather than beside it.