Posterior branches of cervical nerves

Posterior branches of cervical nerves
Posterior primary divisions of the upper three cervical nerves.
Details
From	cervical nerves
Latin	rami posteriores nervorum cervicalium
*Anatomical terms of neuroanatomy* [edit on Wikidata]

The posterior branches of cervical nerves branch from the dorsal rami of the cervical nerves.

Branches

First

The posterior division of the first cervical or suboccipital nerve is larger than the anterior division, and emerges above the posterior arch of the atlas and beneath the vertebral artery. It enters the suboccipital triangle and supplies the muscles which bound this triangle, viz., the Rectus capitis posterior major, and the Obliqui superior and inferior; it gives branches also to the Rectus capitis posterior minor and the Semispinalis capitis. A filament from the branch to the Obliquus inferior joins the posterior division of the second cervical nerve.

The nerve occasionally gives off a cutaneous branch which accompanies the occipital artery to the scalp, and communicates with the greater and lesser occipital nerves.

Second

The posterior division of the second cervical nerve is much larger than the anterior division, and is the greatest of all the cervical posterior divisions. It emerges between the posterior arch of the atlas and the lamina of the axis, below the Obliquus inferior. It supplies a twig to this muscle, receives a communicating filament from the posterior division of the first cervical, and then divides into a large medial and a small lateral branch.

The medial branch (ramus medialis; internal branch), called from its size and distribution the greater occipital nerve, ascends obliquely between the Obliquus inferior and the Semispinalis capitis, and pierces the latter muscle and the Trapezius near their attachments to the occipital bone. It is then joined by a filament from the medial branch of the posterior division of the third cervical, and, ascending on the back of the head with the occipital artery, divides into branches which communicate with the lesser occipital nerve and supply the skin of the scalp as far forward as the vertex of the skull. It gives off muscular branches to the Semispinalis capitis, and occasionally a twig to the back of the auricula.
The lateral branch (ramus lateralis; external branch) supplies filaments to the Splenius, Longus capitis, and Semispinalis capitis, and is often joined by the corresponding branch of the third cervical.

Third

The posterior division of the third cervical is intermediate in size between those of the second and fourth.

Its medial branch runs between the Semispinalis capitis and cervicis, and, piercing the Splenius and Trapezius, ends in the skin. While under the Trapezius it gives off a branch called the third occipital nerve, which pierces the Trapezius and ends in the skin of the lower part of the back of the head. It lies medial to the greater occipital and communicates with it.
The lateral branch often joins that of the second cervical.

The posterior division of the suboccipital, and the medial branches of the posterior division of the second and third cervical nerves are sometimes joined by communicating loops to form the posterior cervical plexus.

Fourth through eighth

The posterior divisions of the lower five cervical nerves divide into medial and lateral branches.

The medial branches of the fourth and fifth run between the Semispinales cervicis and capitis, and, having reached the spinous processes, pierce the Splenius and Trapezius to end in the skin. Sometimes the branch of the fifth fails to reach the skin. Those of the lower three nerves are small, and end in the Semispinales cervicis and capitis, Multifidus, and Interspinales.
The lateral branches of the lower five nerves supply the Iliocostalis cervicis, Longissimus cervicis, and Longissimus capitis.

Additional images

Diagram of the distribution of the cutaneous branches of the posterior divisions of the spinal nerves.
Areas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

Spinal nerves

Cervical	C1 C2 C3 C4 C5 C6 C7 C8 anterior Cervical plexus Brachial plexus posterior Posterior branches of cervical nerves Suboccipital – C1 Greater occipital – C2 Third occipital – C3

Thoracic	T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 anterior Intercostal Intercostobrachial – T2 Thoraco-abdominal nerves – T7–T11 Subcostal – T12 posterior Posterior branches of thoracic nerves

Lumbar	L1 L2 L3 L4 L5 anterior Lumbar plexus Lumbosacral trunk posterior Posterior branches of the lumbar nerves Superior cluneal L1–L3

Sacral	S1 S2 S3 S4 S5 anterior Sacral plexus posterior Posterior branches of sacral nerves Medial cluneal nerves

Coccygeal	anterior Coccygeal plexus posterior Posterior branch of coccygeal nerve

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