FORMATION
- The cervical plexus is formed by the ventral rami of the upper four cervical nerves.
- The rami emerge between the anterior and posterior tubercles of the cervical transverse processes, grooving the costotransverse bars.
- The four roots are connected with one another to form three loops
Position and Relations of the Plexus
The plexus is related:
1. Posteriorly, to the muscles which arise from the posterior tubercles of the transverse processes, i.e.the levator scapulae and the scalenus medius.
2. Anteriorly, to the prevertebral fascia, the internal jugular vein and the sternocleidomastoid.
Branches
Superficial or cutaneous branches
1. Lesser occipital (C2)
2. Great auricular (C2, C3)
3. Transverse (anterior) cutaneous nerve of the neck(c2, c3)
4. Supraclavicular (C3, C4)
Deep Branches
1. Grey rami pass from the superior cervical ganglion to the roots of C1-C4 nerves.
2. A branch from C1 joins the hypoglossal nerve and carries fibres for supply of the thyrohyoid and geniohyoid muscles (directly) and the superior belly of the omohyoid through the ansa cervicalis.
3. A branch from C2 to the sternocleidomastoid and branches from C3 and C4 to the trapezius communicate with the accessory nerve
Muscular Branches
Muscles supplied solely by cervical plexus:
1. Rectus capitis anterior from C1.
2. Rectus capitis lateralis from C1, C2.
3. Longus capitis from C1- C3.
4. Lower root of ansa cervicalis (descendens cervicalis) from C2, C3 (to sternohyoid, sternothyroid and inferior belly of omohyoid.
Muscles supplied by cervical plexus along with the brachial plexus or the spinal accessory nerve:
a. Sternocleidomastoid from C2 along with accessory nerve.
b. Trapezius from C3, C4 along with accessory nerve.
c. Levator scapulae from C3, C4 with C5 (dorsal scapular nerve).
d. Phrenic nerve from C3, C4, C5.
e. Longus colli from C3-C8.
f. Scalenus medius from C3-C8.
g. Scalenus anterior from C4-C6.
h. Scalenus posterior from C6-C8.
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