Posterior Triangle of the Neck

Question 1

What are the attachments of the platysma muscle

Answer 1

Fascia above the pectoralis major and clavicle to the lateral neck and onto the mandible

Question 2

What nerve innervates the platysma muscle

Answer 2

The facial nerve (CN VII)

Question 3

Describe the borders of the posterior triangle

Answer 3

Anterior = posterior border of SCM
Posterior = anterior border of trapezius
Base = clavicle

Question 4

Name the cutaneous nerves of the head and neck

Answer 4

1. Greater occipital
2. Lesser occipital
3. Posterior rami of C3-5
4. Supra-clavicular
5. Transverse cutaneous of neck
6. Greater auricular

Question 5

Where is the C1 dermatome located

Answer 5

It doesn’t exist

Question 6

Describe the orientation of the jugular veins in relation to the SCM

Answer 6

External = anterior
Internal = posterior
Anterior = in the midline of the neck, may be absent

Question 7

What cranial nerve supplying the upper body appears from underneath the SCM

Answer 7

The spinal accessory (CN XI)

Question 8

What arteries lie directly underneath the SCM

Answer 8

1. Suprascapular

2. Transverse cervical

Question 9

Describe the pathway of the phrenic nerve in relation to the scalene muscles

Answer 9

It crosses obliquely over the anterior surface of the anterior scalene

Question 10

Where do the roots of the brachial plexus pass, in relation to the scalene muscles

Answer 10

Between the anterior and middle scalene muscles

Question 11

What nerve provides motor innervation to the SCM

Answer 11

Spinal accessory nerve (CN XI)

Question 12

What nerve provides sensory innervation to the SCM

Answer 12

Cervical plexus; C2, 3

Question 13

What are the actions of the different sections of the trapezius muscle

Answer 13

Ascending = depress scapula
Transverse = retracts scapula
Descending = elevates scapula and rotates the glenoid cavity

Question 14

What nerves innervate the trapezius muscle

Answer 14

1. Spinal accessory nerve (CN XI); motor

2. Cervical plexus C3, 4; sensory

Question 15

What is the innervation of the levator scapulae muscle

Answer 15

Dorsal scapular nerve (C3, 4, 5)

Question 16

What are the actions of the levator scapulae muscle

Answer 16

1. Control scapular position
2. Elevate shoulder (with trapezius)
3. Laterally flex neck to the same side

Question 17

What is the innervation of the scalene muscles

Answer 17

Anterior rami C3-7

Question 18

What are the actions of the scalene muscles

Answer 18

1. Flex neck (bilateral)
2. Tilt head to the same side (unilateral)
3. Elevate the upper ribs

Question 19

Describe the proximal attachment sites of the scalene muscles

Answer 19

Transverse processes of
Anterior = C3-C6
Middle = C2-C7
Posterior = C4-C6

Question 20

Describe the distal attachment sites of the scalene muscles

Answer 20

Anterior = 1st ribs and scalene tubercle
Middle = 1st ribs and groove behind subclavian artery
Posterior = 2nd ribs