Session 11: Cervical Plexus

Question 1

Where can the cervical plexus be found?

Answer 1

Posterior triangle within the prevertebral layer of the cervical fascia.

Question 2

What is the cervical plexus made up of?

Answer 2

Anterior rami of C1-C4

Question 3

Main motor branches of the cervical plexus.

Answer 3

Nerve to genohyoid and thyrohyoid

Ansa cervicalis

Phrenic nerve

Question 4

Where are the motor branches found in relation to the sensory branches?

Answer 4

Deep to the sensory branches.

Question 5

Root value of phrenic nerve.

Answer 5

C3-C5

Question 6

Route and supply of the phrenic nerve.

Answer 6

Originates from the cervical plexus and descends down the anterior scalene to enter the thoracic cavity.

It then descends anterior to the root of the lung and innervates the diaphragm.

Question 7

Root value of the nerve to genohyoid and thyrohoid.

Answer 7

C1

Question 8

Action of geniohyoid?

Answer 8

Moves hyoid bon anteriorly and upwards to expand the airways.

Question 9

Action of thyrohyoid.

Answer 9

Depresses the hyoid bone and elevates the larynx.

Question 10

What does the nerves to geniohyoid and thyrohyoid travel with?

Answer 10

The hypoglossal nerve

Question 11

Root value of ansa cervicalis.

Answer 11

C1-C3

Question 12

What does ansa cervicalis innervate?

Answer 12

Infrahyoids

Question 13

What do the sensory branches of the cervical plexus innervate?

Answer 13

Skin of neck, upper thorax, scalp and ear.

Question 14

Explain the common route of the sensory branches of the cervical plexus.

Answer 14

Enter the skin at the middle point of the posterior border of SCM.

Question 15

What is Erb’s point?

Answer 15

The point of which the sensory branches exit the cervical plexus.

Middle point of the posterior border of SCM.

Question 16

Main sensory branches of the cervical plexus.

Answer 16

Greater auricular nerve

Transverse cervical nerve

Lesser occipital nerve

Supraclavicular nerves

Question 17

Nerve roots of greater auricular nerve.

Answer 17

C2,C3

Question 18

What does the greater auricular nerve innervate?

Answer 18

External ear and the skin over parotid gland.

Also comunicates with the auricular branch of the vagus nerve and the posterior auricular branch of facial nerve.

Question 19

Nerve roots of transverse cervical nerve

Answer 19

C2,C3

Question 20

What does the transverse cervical nerve innervate.

Answer 20

Anterior skin of neck and piereces deep cervical fascia to also supply anterolateral skin of neck and sternum.

Question 21

Nerve roots of lesser occipital nerve.

Answer 21

Mainly C2

In some individuals C3 can contribute slightly.

Question 22

What does the lesser occipital nerve innervate?

Answer 22

Curves around the accessory nerve to supply the posterosuperior scalp.

Question 23

Nerve roots of the supraclavicular nerves.

Answer 23

C3,C4

Question 24

What does the supraclavicular nerves innervate?

Answer 24

Supraclavicular fossa

Upper thoracic region

Sternoclavicular joint