The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve. It arises from
second cervical (spinal) nerve (along with the
greater occipital nerve). It innervates the
scalp in the lateral area of the
head
A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...
posterior to the
ear.
Structure
The lesser occipital nerve is one of the four cutaneous branches of the
cervical plexus
The cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which arise from C1 to C4 cervical segment in the neck. They are located laterally to the transverse processes between prevertebral muscles from the medi ...
.
Origin
It arises from the (lateral branch of the
ventral ramus) of
cervical spinal nerve C2; it may also receive fibres from
cervical spinal nerve C3.
It originates between the
atlas, and
axis.
Course and relations
It curves around the
accessory nerve (CN XI) to come to course anterior to it.
It then
curves around
and ascends along the posterior border of the
sternocleidomastoid muscle;
rarely, it may pierce the muscle.
Near the cranium, it perforates the
deep fascia. It is continues upwards along the scalp posterior to the
auricle.
Distribution
The lesser occipital nerve distributes branches to the skin.
It gives off an auricular branch, which supplies the skin of the upper and back part of the auricula, communicating with the
mastoid branch
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, ...
of the
great auricular
The great auricular nerve is a cutaneous nerve of the head. It originates from the cervical plexus, with branches of spinal nerves C2 and C3. It provides sensory nerve supply to the skin over the parotid gland and the mastoid process of the temp ...
. This branch is occasionally derived from the
greater occipital nerve.
Variation
Rarely, the lesser occipital nerve may be duplicated or triplicated.
It varies in size.
Function
The lesser occipital nerve supplies part of the
scalp near the
auricle.
It connects with the
great auricular nerve, the
greater occipital nerve, and the
auricular branch of the facial nerve.
Clinical significance
Problems with the lesser occipital nerve cause
occipital neuralgia
Occipital neuralgia (ON) is a painful condition affecting the posterior head in the distributions of the greater occipital nerve (GON), lesser occipital nerve (LON), third occipital nerve (TON), or a combination of the three. It is paroxysmal, la ...
.
Nerve block is difficult due to variation in the course of the nerve.
History
The lesser occipital nerve may also be known as the occipitalis minor nerve,
or the small occipital nerve.
Additional images
File:Gray784.png, Dermatome distribution of the trigeminal nerve
References
External links
*
* http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-2.HTM
* http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-6.HTM
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Optic nerve