Lecture 4 - Posterior triangle of neck

Question 1

Why is poterior triangle important?

Answer 1

• Can look at the JVP
• Central vien catheterisation
• Penetrating trauma - need to know structures so can remove
• Cervical lymphadenopathy - alot of lymph nodes in this region
• good place to do a brachial plexus block

Question 2

What innovates platysma muscle?

Answer 2

Facial nerve

Question 3

Different layers of fascia in the neck?

Answer 3

Superficial - platysma muscle (facial nerve)

Deep
Investing layer - around trapzius, SCM, lower facial muscles
Pretracheal layer - thyroid, trachea, esophagus ect,
Carotid sheet (combination of all) - ICA, IJV, vagus nerve
Pre vertebral layer- around vertebral column and muscles

Question 4

** What superficial nerves provide sensation of neck (both ant and posterior triangle)
What is erbs point?

Answer 4

In charge of sensation of whole neck (cutaneous nerves)

Transverse cervical
lesser occipital nerve
greater auricular
supra clavicular

• come from cervical plexus
• these nerves run in one bundle up until erbs point, and as soon as they reach the posterior triangle of neck they branch
• go to the superficial fascia

Question 5

What are the three arteries running into this triangle?

Answer 5

Are mainly at bottom of posterior triangle (thyrocervical branch of subclavian)

• Transverse cervical artery
• Supraclavicular
• 3rd part of Subclavian (do not want to put a needle here)

Question 6

Accessory nerve?
-what is one layer superficial, and one layer deeper

What nerves are in the posterior triangle

Answer 6

• one layer deep to erbs point
• innovates sternocleidomastoid and trapezius
• spinoaccesory nerve - has a spine and cranial nerve (accessory nerve)
• brachial plexus
• lymph nodes are one layer deeper - dont want to damage accessory nerve when getting to lymph nodes

-USE AN ULTRASOUNDS - so dont damage

Question 7

Where would you put your needle if doing a brachial plexus block?

Answer 7

lower part of the posterior triangle

Question 8

What do you need to be careful of when doing surgery on lymph nodes?

Lymph node biopsy?

Answer 8

accessory nerve runs one plane superficial to the lymph nodes, dont want to damage

Question 9

What do superficial and deep lymph nodes run with?

Answer 9

Superficial - with external jugular vien (and around base of skull) - occipital nodes, mastoid, submental, submandibular nodes ect.

• have superficial and deep cervical lymph nodes
• one that runs with external jugular vien - superficial
• ones that run with internal jugular vien are deep

-superficial lymph nodes go to deep lymph nodes
Deep - with IJV

Question 10

Central vien catherterisation

Answer 10

Ultrasound neck
put probe into IVC

put patient in trendelenburg position with contralateral rotation of the head in order to dilate the IJV

• point at which the vien crosses the posterior border of the sternocleidomastoid is key landmark
• use ultrasound

Question 11

What are the boundaries?

If putting a needle in, what would you travel through?

Answer 11

page 30

Roof - made of skin, subcutaneous tissue, platysma muscle, superficial platysma muscle and superficial cutaneous nerves and veins

Question 12

Paper

Answer 12

Aim - to determine course of SAN

• used ultrasound
• commonly damaged in lymph node biopsys

You can visualise SAN using ultrasound

• The course of SAN cannot be reliably predicted by surface anatomy alone
• Posterior Triangle dissection is complicated due to branching of SAN; ultrasound usage or referral should both be considered

–> paralysis of trapezius and SNM