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

cervical nerve A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the ...

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 The vertebral arteries are major arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry o ...

. It enters the suboccipital triangle and supplies the muscles which bound this triangle, viz., the Rectus capitis posterior major, and the

Obliquus capitis superior The obliquus capitis superior muscle () is a small muscle in the upper back part of the neck and is one of the suboccipital muscles and part of the suboccipital triangle. It arises from the lateral mass of the atlas bone. It passes superiorly a ...

and

Obliquus capitis inferior The obliquus capitis inferior muscle () is the larger of the two oblique muscles of the neck. It arises from the apex of the spinous process of the axis and passes laterally and slightly upward, to be inserted into the lower and back part of the t ...

; it gives branches also to the

Rectus capitis posterior minor The rectus capitis posterior minor (or rectus capitis posticus minor, both being Latin for ''lesser posterior straight muscle of the head'') arises by a narrow pointed tendon from the tubercle on the posterior arch of the atlas, and, widening as i ...

and the Semispinalis capitis. A filament from the branch to the Obliquus capitis 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 capitis 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 capitis 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, Longissimus 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 While under the Trapezius The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves ...

, 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 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 ...

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

Semispinalis cervicis The semispinalis muscles are a group of three muscles belonging to the transversospinales. These are the semispinalis capitis, the semispinalis cervicis and the semispinalis thoracis. The semispinalis capitis (''complexus'') is situated at the ...

and capitis, Multifidus, and

Interspinales The interspinales are short muscle fascicles, found in pairs between the spinous processes of the contiguous vertebrae, one on either side of the interspinal ligament. * In the cervical region the ''cervical interspinales'' are most distinct, ...

. * The ''lateral branches'' of the lower five nerves supply the Iliocostalis cervicis, Longissimus cervicis, and Longissimus capitis.

Additional images

File:Gray801.png, Diagram of the distribution of the cutaneous branches of the posterior divisions of the spinal nerves. File:Gray802.png, Areas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves.

References

Spinal nerves {{Portal bar, Anatomy