see also:

• headache
• migraine

• headaches arising from irritation in the upper neck are very common and can cause unilateral temporal/retro-orbital headaches as well as occipital headaches and can precipitate migraine
• a common site of irritation is at C2/3 or C3/4 facet joints which are postero-lateral and often involved in degenerative or arthritic pathology, or acutely if prolonged stresses are applied such as during sleep, holding phone by the head/neck being angled for long periods, or in acute trauma
• much less common than C5/6 disc prolapses, C2 or C3 discs may also prolapse and impinge the nerve roots

• formed by the articulation of the superior articular process (SAP) which is the contribution of the vertebra above and the inferior articular process(IAP), which in turn is the contribution of the vertebra below
• they have an angled orientation of around 45 degrees, superior to the transverse plane (the orientation attaining a more vertical pattern by C8/T1)
• each facet joint is enveloped in a fibrous capsule which is further lined by a synovial membrane.
• pain from cervical joints are transmitted via:
  • atlanto-occipital and atlanto-axial joints:
    • branches of the C1 and C2 of the ventral rami
  • C2/3 facet joint:
    • two separate branches of the C2 and C3 dorsal rami (check if it is both!):
      • “the third occipital nerve”
      • an articular branch arising from the origin of the communicating branch or from the communicating branch itself
  • C3/4 to C8/T1 facet joints:
    • Cervical Medial branch nerves
      • these are very small nerves and can be blocked with local anaesthetic, or longer term blocks via radiofrequency ablation
• pain from cervical facet joints is also called cervical facet syndrome

• the cutaneous branches of the cervical plexus transmit sensory information from the skin of the neck, the superior portions of the thorax, and the scalp
  • these nerves emerge from a common point at the posterior aspect of the sternocleidomastoid, known as Erb’s point near the mid-point of the sternocleidomastoid
  • lesser occipital nerve arises from C2 and supplies the skin of the neck and the scalp posterior and superior to the auricle
  • greater auricular nerve of C2 and C3 ascends anterior to the auricle and supplies the skin over the parotid gland, the mastoid process, and the skin from the parotid gland to the mastoid process
  • transverse cervical nerve, of C2 and C3, projects posteriorly and wraps around anteriorly to supply the skin of the anterior cervical region.
  • supraclavicular nerve, of C3 and C4, descends from the posterior sternocleidomastoid and provides sensory information from the skin over the clavicle and shoulder.

• C1 spinal nerve gives rise to the nerve to the geniohyoid and the nerve to the thyrohyoid (these nerves travel closely to the hypoglossal nerve (CN XII) )
• provides supply to ansa cervicalis via the superior root (see under C2)
• also supplies rectus capitis anterior/lateralis (with C2), and longus capitis (with C2/C3/4/5)
• Sympathetic connections

• the C2 nerve root may become irritated due to degeneration of the C2/3 facet joint or adjacent structures
• the second cervical nerve, is part of the cervical plexus, which forms from the ventral rami of C1 to C4.
• the C2 nerve gives rise to several branches that supply different areas of the head and neck including:
  • Lesser Occipital Nerve:
    • arises from C2 and supplies the skin of the neck and the scalp posterior and superior to the auricle
  • Greater Auricular Nerve:
    • formed by fibers from C2 and C3.
    • ascends anterior to the auricle and supplies the skin over the mastoid process, and the skin from the parotid gland to the mastoid process
  • Transverse Cervical Nerve:
    • formed by fibers from C2 and C3.
    • projects posteriorly and wraps around anteriorly to supply the skin of the anterior cervical region
  • Least or Third Occipital Nerve:
    • crosses the dorsal aspect of the C2/C3 zygapophyseal joint which it supplies. It then continues towards the skull, deep to the semispinalis muscle.
    • after passing the spinal process of C2, the nerve pierces the semispinalis muscle, splenius capitis and trapezius, and continues towards the skull superficially
  • Ansa Cervicalis
    • along with C1 and C3, C2 also provides supply to this plexus with C2 and C3 supplying via the inferior root
    • all of the muscles supplied by branches of the ansa cervicalis, along with the thyrohyoid, are infrahyoid muscles, and therefore serve to depress the hyoid bone - this function is necessary for proper speech and swallowing
    • supplies sup. (mainly C1) and inf bellies of omohyoid, sternohyoid, sternothyroid
  • Meningeal Branch:
    • C2 nerve gives off a small meningeal branch which reenters the vertebral canal through the intervertebral foramen and supplies the vertebrae and their ligaments
  • Sympathetic connections
    • ventral rami that compose the cervical plexus each receive gray rami communicates from the superior cervical ganglion of the sympathetic trunk

• provides supply to ansa cervicalis via the inferior root (see under C2)
• C3, C4, and C5 roots contribute to form the phrenic nerves
• longus capitis (along with C1/2/4/5)
• trapezius (sensory) - along with C2 and C4
• Sympathetic connections