The Cervical Plexus
The cervical plexus originates from the anterior rami of C1-C4 that combine into 3 loops from which the deep and superficial branches arise.
Muscular (deep) branches are:
– The phrenic nerve (C3-C5) provides innervation to the diaphragm
– Nerves to the geniohyoid and thyrohyoid (C1) relevant to airway and respiratory function
– Ansa cervicalis (C1-C3) supplying muscles important for swallowing and speech
TIP: The muscular branches are essential to consider due to the potential adverse effects related to a deep cervical plexus block
The superficial branches emerge from the prevertebral fascia in between the longus capitis and the middle scalene muscle and run posterior along the deep fascia of the sternocleidomastoid muscle (SCM). The SCM forms a “roof” over these branches which then emerge from behind the posterior border of the muscle approximately at the intersection with the external jugular vein (Erb’s point).
List of the superficial branches:
– Greater auricular nerve
– Lesser occipital nerve
– Transverse cervical nerve
– Supraclavicular nerves