Cervical plexus and dermatomes of the neck (dave's notes)

Question 1

How is the cervical plexus formed?

Answer 1

By simple loops between the anterior rami of the upper four cervical nerves after each has received a grey ramus from the superior cervical ganglion. This is continuous with the brachial plexus.

Question 2

What type of nerves does the cervical plexus give off?

Answer 2

Muscular and cutaneous nerves, proprioceptive to trapezius

Question 3

List the muscular nerves arising from the cervical plexus, their nerve roots, and what they supply

Answer 3

• Muscular branches are given off segmentally to the prevertebral muscles
• Hypoglossal nerve, C1, to thyrohyoid and geniohyoid
• C2, C3 to SCM
• C3, C4 to trapezius (proprioceptive)
• Inferior root of ansa cervicalis
• Phrenic nerve C4 (+ C3, C5)

Question 4

List the cutaneous nerves of the cervical plexus. What is the gross region that they supply?

Answer 4

They supply the front and sides of the neck.
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular

Question 5

Describe the lesser occipital nerve

Answer 5

A slender branch hooking around the accessory nerve

Question 6

Describe the great auricular nerve

Answer 6

A larger trunk supplying skin over the side of the face

Question 7

Describe the supraclavicular nerve

Answer 7

The supraclavicular nerve emerges at the posterior border of SCM and divides into three main groups:

• Medial skin down to the sternal angle
• Intermediate as far down as the anterior axial line
• Lateral skin half way down deltoid and the posterior aspect of the shoulder.

Question 8

What supplies the sensory fibres to the skin of the neck

Answer 8

The greater occipital and third occipital from the posterior ramie are the sensory fibres

Question 9

What supplies most of the posterior part of the neck, up to the scalp and forward to the auricle?

Answer 9

C2

Question 10

What supplies the skin over the cylindrical part of the neck?

Answer 10

C3

Question 11

What supplies the skin over the clavicular region across the top of the shoulder and down to the scapular spine?

Answer 11

C4

Question 12

What skin does C2 supply?

Answer 12

Most of the posterior part of the neck, up to the scalp and forward to the auricle

Question 13

What skin does C3 supply?

Answer 13

The skin over the cylindrical part of the neck

Question 14

What skin does C4 supply

Answer 14

The skin over the clavicular region across the top of the shoulder and down to the scapular spine