The greater occipital nerve is a spinal nerve

Spinal nerve

The term spinal nerve generally refers to a mixed spinal nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body...

, specifically the medial branch of the dorsal primary ramus of cervical spinal nerve 2. This nerve arises from between the first and second cervical vertebrae

Cervical vertebrae

In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...

, along with the lesser occipital nerve

Lesser occipital nerve

The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve arising between the second and third cervical vertebrae, along with the greater occipital nerve...

. It ascends after emerging from the suboccipital triangle

Suboccipital triangle

The suboccipital triangle is a region of the neck bounded by the following three muscles of the suboccipital group of muscles:* Rectus capitis posterior major - above and medially* Obliquus capitis superior - above and laterally...

 obliquely between the inferior oblique and semispinalis capitis

Semispinalis capitis

The Semispinalis capitis is situated at the upper and back part of the neck, deep to the Splenius, and medial to the Longissimus cervicis and capitis....

 muscle. It then passes through the trapezius muscle and ascends to innervate the skin along the posterior part of the scalp

Scalp

The scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly.-Layers:It is usually described as having five layers, which can conveniently be remembered as a mnemonic:...

 to the vertex

Vertex (anatomy)

In arthropod and vertebrate anatomy, the vertex refers to the upper surface of the head.In humans, the vertex is formed by four bones of the skull: the frontal bone, the two parietal bones, and the occipital bone...

. It innervates the scalp at the top of the head, over the ear

Ear

The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....

 and over the parotid glands.

Clinical relevance

Disorder of this nerve is one of the causes of cervicogenic headaches, referred to as occipital neuralgia

Occipital neuralgia

Occipital neuralgia, also known as C2 neuralgia, Arnold's neuralgia, is a medical condition characterized by chronic pain in the upper neck, back of the head and behind the eyes. These areas correspond to the locations of the lesser and greater occipital nerves.-Causes:Occipital neuralgia is...

s. A common site, and usually misdiagnosed area of entrapment for the greater occipital nerve is at the obliquus capitis inferior muscle.

External links

• Image at theberries.ns.ca
• http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-2.HTM
• http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-6.HTM