Posterior Triangle

Question 1

Superficial cervical fascia

Answer 1

Fatty tissue + platysma

Question 2

Platysma

Answer 2

Thin sheet of skeletal muscle that originates from the superficial fascia of the thorax and runs upward to attach to the mandible and blend with the lower facial muscles

Question 3

Platysma innervation

Answer 3

Cervical branch of facial nerve

Question 4

Deep cervical fascia

Answer 4

Investing layer
Pretracheal layer
Carotid sheath
Prevertebral layer

Question 5

Carotid sheath

Answer 5

Formed by combination of investing, pretracheal and prevertebral layers of superficial cervical fascia
Contains common carotid artery, internal jugular vein and the vagus nerve

Question 6

Investing layer

Answer 6

Encloses the peripheral muscles around the neck e.g. sternocleidomastoid, trapezius, strap muscles

Question 7

Pretracheal layer

Answer 7

Encloses thyroid, larynx/trachea and pharynx/oesophagus

Question 8

Prevertebral layer

Answer 8

Encompasses the vertebral column and the paravertebral muscles

Question 9

Investing layer attachments

Answer 9

Superiorly to external occipital protuberance and superior nuchal line
Laterally to mastoid process and zygomatic arch
Inferiorly to spine, clavicle, acromion and manubrium

Question 10

Cervical spaces

Answer 10

Pretracheal space
Retropharyngeal space
Prevertebral space

Question 11

Pretracheal space

Answer 11

Region between investing layer and pretracheal layer

Extends inferiorly from larynx/pharynx down to the anterior part of the superior mediastinum

Question 12

Retropharyngeal space

Answer 12

Situated between the posterior aspect of the pharynx/oesophagus and the prevertebral layer
Extends inferiorly from the base of the skull to the upper part of the posterior mediastinum

Question 13

Prevertebral space

Answer 13

Potential space within the prevertebral layer between the vertebral bodies posteriorly and the prevertebral fascia anteriorly, limited laterally by the transverse processes and extending from the base of the skull t the diaphragm

Question 14

Contents of the posterior triangle

Answer 14

3 arteries – transverse cervical, supraclavicular, third part of the subclavian
2 nerves –accessory nerve and greater occipital nerve
1 muscle – inferior belly of omohyoid
1 vein - external jugular vein
2 plexus - trunks of brachial plexus and cutaneous branches of cervical plexus

Question 15

Boundaries of the posterior triangle

Answer 15

Anterior: posterior border of SCM
Posterior: anterior border of trapezius
Base: middle third of clavicle
Apex: back of the skull on the superior nuchal line
Roof: investing layer of deep fascia
Floor: prevertebral fascia

Question 16

Spinal accessory nerve

Answer 16

Very superficial and located very close to lymph nodes, so very commonly damaged in lymph node biopsies
Ultrasounds are key in predicting the course

Question 17

Plexus in the posterior triangle

Answer 17

The cervical plexus

Part of the brachial plexus

Question 18

Path of occipital artery and greater occipital nerve in the posterior triangle

Answer 18

Emerge from the apex and run upward onto the scalp. Occipital lymph nodes also found at the apex.

Question 19

Path of accessory nerve in the posterior triangle

Answer 19

Embedded in the investing fascia and enters halfway down the posterior edge of the sternocleidomastoid, runs downward over the floor and exits by penetrating the anterior edge of the trapezius a few cm above the clavicle

Question 20

Path of external jugular vein in the posterior triangle

Answer 20

Passes vertically down the neck from behind the angle of the mandible over the sternocleidomastoid and pierces the investing fascia in the anterior corner of the posterior triangle and joins the subclavian vein

Question 21

Central venous catheterisation

Answer 21

Inserted via the internal jugular vein, the subclavian vein or their junction
Key to find two heads of sternocleidomastoid and catheterise between them to avoid the vagus nerve
Ultrasound guidance should be used if available