Lesser occipital nerve

The lesser occipital nerve (or small occipital nerve<ref name=":2">Template:Citation</ref>) is a cutaneous spinal nerve of the cervical plexus.<ref name=":0222">Template:Cite book</ref> It arises from second cervical (spinal) nerve (C2) (along with the greater occipital nerve). It innervates the skin of the back of the upper neck and of the scalp posterior to the ear.

Structure

Origin

It arises from the (lateral branch of the ventral ramus<ref name=":33" /><ref name=":0" />) of cervical spinal nerve C2;<ref name=":33" /><ref name=":0" /><ref name=":0222" /> it (sources differ) receives<ref name=":2" /> or may also receive fibres from cervical spinal nerve C3.<ref name=":33">Template:Cite book</ref><ref name=":0">Template:Cite book</ref> It originates between the atlas, and axis.<ref name=":0" />

The lesser occipital nerve is one of the four cutaneous branches of the cervical plexus.<ref name=":1">Template:Cite book</ref>

Course and relations

It curves around the accessory nerve (CN XI)<ref name=":0" /><ref name=":33" /><ref name=":022">Template:Cite book</ref> to come to course anterior to it.<ref name=":33" /> It then<ref name=":33" /> curves around<ref name=":0" /> and ascends along the posterior border of the sternocleidomastoid muscle;<ref name=":33" /><ref name=":0" /><ref name=":022" /> rarely, it may pierce the muscle.<ref name=":0" /> Near the cranium, it perforates the deep cervical fascia. It is continued upwards along the scalp posterior to the auricle.<ref name=":33" /><ref name=":0" /> It divides into medial and lateral segments between the inion, and intermastoid line.<ref name=":2" />

Branches

It has an auricular, a mastoid, and an occipital branch.<ref name=":2" />

Its auricular branch supplies the skin of the upper and back part of the auricula, communicating with the mastoid branch of the great auricular. This branch is occasionally derived from the greater occipital nerve.Template:Citation needed

Distribution

The nerve provides sensory innervation to the upper part of the back of the neck and adjacent<ref name=":022" /> scalp posterior to the auricle;<ref name=":022" /><ref name=":2" /> it may also contribute to the sensory innervation of the auricle itself.<ref name=":022" />

Communications

It communicates with the greater occipital nerve,<ref name=":0" /><ref name=":2" /> great auricular nerve, and the auricular branch of the facial nerve.<ref name=":0" />

Variation

Rarely, the lesser occipital nerve may be duplicated or triplicated.<ref name=":0" />

Clinical significance

Problems with the lesser occipital nerve cause occipital neuralgia. Nerve block is difficult due to variation in the course of the nerve.<ref name=":0" />

Additional images

• Gray784.png

  Dermatome distribution of the trigeminal nerve

References

<references />

External links

• Template:SUNYAnatomyFigs
• http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-2.HTM
• http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-6.HTM