The cervical plexus is a nerve plexus of the anterior rami of the first (i.e. upper-most) four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory innervation to parts of the head, neck, and chest.
The branches of the cervical plexus emerge from the posterior triangle at the nerve point, a point which lies midway on the posterior border of the sternocleidomastoid.
Relations
The cervical plexus is situated deep to the sternocleidomastoid muscle, internal jugular vein, and deep cervical fascia.
- Muscular
- Ansa cervicalis - a loop formed by C1-C3 that supplies most infrahyoid (a.k.a. "strap") muscles (sternothyroid, sternohyoid, omohyoid muscles) etc.
- Nerve to thyrohyoid - fibres from C1 that run with the hypoglossal nerve (cranial nerve XII) and do not participate in the formation of the superior root of ansa cervicalis, instead continuing for some further distance to reach and innervate the thyrohyoid muscle and the geniohyoid muscle.
- Phrenic (C3-C5, but mostly C4) - innervates thoracic diaphragm and the pericardium.
- Segmental branches (C1-C4) - innervate anterior and middle scalene muscles
- Levator scapulae muscle (C3-C4) (also innervated by dorsal scapular nerve (C5) of the brachial plexus)
Diagram
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Additional images
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Image:Gray804.png|Plan of the cervical plexus.
Image:Gray805.png|The nerves of the scalp, face, and side of neck.
Image:Gray838.png|The right sympathetic chain and its connections with the thoracic, abdominal, and pelvic plexuses.
Image:Gray1210.png|Side of neck, showing chief surface markings.
</gallery>