Spinalis capitis muscle
Musculus spinalis capitis
Spinalis capitis is a thin, often indistinct strand of the erector spinae that reaches the skull from the upper thoracic and lower cervical spines.
At a glance
- English
- Spinalis capitis muscle
- Latin (TA2)
- Musculus spinalis capitis
- System
- Muscle
- Region
- Neck
- Side
- Paired, left and right
About the spinalis capitis muscle
Spinalis capitis is the uppermost part of the spinalis column, the most medial of the three columns of erector spinae. It is small and poorly defined, and many modern atlases leave it out altogether. Older texts called it biventer cervicis. In most bodies it cannot be peeled cleanly away from semispinalis capitis, with which it shares its course and its attachment on the skull.
When it can be traced, it is a set of fibres arising from the spinous processes of the upper thoracic and lowest cervical vertebrae, usually T1 and C7, sometimes from more of the upper thoracic spines. These fibres climb close to the midline in the back of the neck and reach the occipital bone between the superior and inferior nuchal lines, where they blend with the medial part of semispinalis capitis.
Because it passes from the spine to the skull, its main work is to extend the head and neck when both sides act. Acting on one side it may help to tilt the head towards that side. In practice its action cannot be separated from that of semispinalis capitis, which is far larger and does most of the work of holding the head up and drawing it back.
Spinalis capitis lies deep to trapezius and splenius capitis and medial to semispinalis capitis. Its small size means it has little clinical importance of its own, but it is part of the deep neck extensor mass that is involved in neck strain, postural neck pain and the treatment of whiplash-type injuries.
Attachments, action and supply
- Origin
- Spinous processes of the lowest cervical and upper thoracic vertebrae, mainly C7 and T1.
- Insertion
- Occipital bone between the superior and inferior nuchal lines, blended with semispinalis capitis.
- Action
- Helps to extend the head and neck; on one side may help to tilt the head to that side.
- Nerve supply
- Dorsal rami of the lower cervical and upper thoracic spinal nerves.
- Blood supply
- Deep cervical and occipital arteries.
Anthromica
See the spinalis capitis muscle where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
