Nerve Innervations of the Head and Neck

Question 1

What spinal nerves form the Cervical Plexes?

Answer 1

Ventral Ramii of C1-C4

Question 2

Name the 5 types of branches of the Cervical Plexes

Answer 2

5 types of branches:

Cutaneous branches (goto the skin)

Communicating or hitchhiker branches

Ansa Cervicalis n.

Phrenic n.

Motor branches-to muscles of deep ant. neck

Question 3

Name the 4 main terminal branches of the Cutaneous branches and where do they exit from.

Answer 3

4 main branches:

Lesser occipital n.

Great auricular n.

Transverse cervical n.

Supraclavicular nerves- medial, intermediate and lateral

All exit posterior border to the SCM into the posterior triangle of the neck.

Question 4

Name the nerve origin and the the innervation of the Lesser occipital n.

Answer 4

O: C2 fibers of the ventral rami

N: Skin of posterior scalp behind the ear

Question 5

Name the nerve origin and the innervation of the Great auricular n.

Answer 5

O: C2, C3 fibers of the ventral ramii

N: Sensory– to skin below and ant. to external ear and part of ear, and skin over the angle of mandible

Question 6

Name the nerve origin and innervation of the Transverse cervical n.

Answer 6

O: C2, C3 ventral ramii

N: Innervates most skin of the ant. neck, terminal branches penetrate the platysma mm

Question 7

Name the nerve origin and the innervation of the Supraclavicular n

Answer 7

O: C3, C4 ventral ramii, radiates across the clavicular region and has 3 branches:

medial –intermediate– lateral

N: skin of base of neck, upper thorax, and top of the shoulder

Question 8

Define communicating/hichhiker nerve branches

Answer 8

They are nerves that join nerves en route to their destinations, but are not really part of those nerves

Question 9

Name the Communicting nerves in the neck and what they innervate.

Answer 9

C3, C3 and C4 fibers join cranial nerve Xl Spinal Accessory n.

Provide sensory innervation (with some motor) to SCM -C2 (3) and Trapezius- C3, C4

Question 10

What do C1 and C2 fibers join with and what do they innervate?

Answer 10

C1 fibers (and sometimes C2) join with cranial n. Xll hypoglosseal n and supplies motor innervation to tongue as well as the geniohyoid and thyrohyoid mm

Question 11

Define Ansa Cervicalis

Answer 11

Ansa=Loop

Cervicalis= from cervical plexes

A nerve loop in the neck containing to roots

Question 12

What is the Ansa Cervicalis comprised of ?

Answer 12

It is comprosed of ventral ramii of C1,C2,C3 ans supply all the motor innervation to infrahyoid mm EXCEPT the Thyrohyoid mm.

Question 13

Name and describe the 2 roots of the Ansa Cervicalis

Answer 13

1- Superior Root of Ansa Cervicalis – ventral rami C1—Hithchikes on cranial n. Xll for a chort distance, so it is called the Descending Hypoglosseal Ramus of Ansa Cervicalis

2-I_nferior Root of Ansa Cervicalis_–ventral rami C2-C3 also called the Descending Cervical Ramus of Ansa Cervicalis

Together these roots supply:

Sternohyoid mm

Sternothyroid mm

Omohyoid mm

Question 14

Where is the Phrenic n. located, its nerve origin and its innervation?

Answer 14

It is located along the ant. surface of ant. Scalene mm

O: ventral rami C3-C5

N: Motor and sensory to the diaphragm

Question 15

What muscles do the motor branches of teh cervical plexes supply?

Answer 15

The deep ant. neck mm. :

Scalene mm

Prevertebral mm