Posterior Triangle of the Neck

Question 1

What is the posterior triangle of the neck clinically important for?

Answer 1

• Indirectly measure the Jugular Venous Pressure (JVP)
• For Central Vein Catheterisation (CVC)
• Penetrating trauma in this area means we need to know anatomy?

Question 2

What do we most commonly see going wrong int the Post.triangle?

Answer 2

Cervical Lympadenopathy (enlarged lymph nodes).
SF cervical LN's in this region will have cancer cells draining through them.

Question 3

What are the layers of cervical fascia?

Answer 3

1. Superficial layer (skin)
2. Deep fascia

Question 4

Describe the SF fascia of the posterior triangle

Answer 4

Contains fatty tissue + platysma muscle (innervated by CN VIII; cervical branch)

Question 5

Platysma is?

Answer 5

Thin sheet of skeletal muscle that originates from the SF fascia of the thorax/clavicle to run upwards, attaching onto the mandible and blending with the lower facial muscles.

A muscle of ‘expression’!

Innervated by VIII cervical branch

Question 6

Describe the Deep Fascia of the Posterior Triangle

Answer 6

1. Investing (SF) Layer: like a stocking around peripheral neck muscles trapezius, SCM and strap muscles
2. Pretracheal (medial) Layer: enloses thyroid, larynx/trachea and pharynx/eosophagus
3. Prevertebral (deep) Layer: encloses vertebral column and paravertabral muscles

Question 7

Why is it clinically important to know about the cervical fascias?

Answer 7

In terms of cancer, in terms of terming invasion levels by looking at the extend of the fascia cancer spread

Question 8

What’s the Carotid Sheath and what does it enclose?

Answer 8

Not a fascia itself, but a contribution from the existing 3 layers of the Deep Fascia. Therefore it is NOT a seperate entity/distinct fascia but instead a contribution of the other fascia.

• Internal Carotid Artery
• Internal Jugular Vein
• Vagus nerve (CN X)

Question 9

The Common Carotid runs up and ________ into the ________ and ________. Then only the ______ lies within the carotid sheath.

Answer 9

The Common Carotid runs up and Bifurcates into the internal carotid Artery and external carotid artery. Then only the internal carotid lies within the carotid sheath. (the external carotid goes out to the other spaces of the neck).

So CC at the bottom of the neck and only IC at the top

Question 10

Why are cervical Spaces ‘not real’ spaces of the neck?

Answer 10

They are infact potential spaces of the necks where disease may spread (locally from nek to mediastinum) BUT if you open someone up you’ll probably be unable to find them!

You can see them in a cross-sectional MRI, especially in disease.

Question 11

What are the Cervical spaces of the Neck?

Answer 11

1. Pretracheal Space: between investing and pretracheal layer. Extends inferiorly from pharynx/larynx → ant. superior mediastinum
2. Retropharyngeal Space: Between oesophagus and prevertebral space. Extends inferiorly from base of skull → upper part of post. mediastinum.
3. Prevertebral Space: within the prevertebral layer between the prevertebral fascia ant. and the vertebral bodies post. (Limited by the transverseprocesses lat.) From base of skull → diaphragm

Question 12

Draw out the Regions of the neck.

Answer 12

Question 13

What are the Boundaries of the Posterior triangle aka Region V?
Borders

Roof

Neck

Answer 13

Anterior: posterior border of the sternocleidomastoid
Posterior: anterior border of Trapezius
Base: middle 1/3 of the clavicle
Roof: skin+platysma+fatty tissue with cutaneous nerves and veins upto the investing layer of Deep Fascia
Floor: prevertebral fascia

Question 14

Contents of the Posterior Triangle

Answer 14

• NV structures
• Lymph nodes
• Muscular Structures

READ PAGE 31 FOR ALL THE DETAIL!!