Posterior Triangle

Question 1

What’s embedded in the substance of the deep fascia of the roof of the posterior triangle?

Answer 1

The spinal root of accessory.

Question 2

What fascia forms the roof of the posterior triangle and which forms the floor?

Answer 2

The roof by the superficial and investing layer of deep fascia
The floor by the prevertebral fascia

Question 3

What are the contents of the posterior triangle? (Muscle, nerves, arteries and LNs)

Answer 3

Muscle: inferior belly of omohyoid
Nerves: cutaneous and muscular branches of the cervical plexus and spinal root of accessory nerve.
Arteries: third part of the subclavian, suprascapular and transverse cervical artery.
Vein: the lower part of the external jugular vein.

Question 4

What’s the sensory (proprioceptive) supply of the sternomastoid?

Answer 4

Ventral rami or C 2 and 3

Question 5

What’s the superficial relations of the sternomastoid?

Answer 5

Skin, fascia, platysma
Transverse cutaneous nerve and great auricular nerves, posterior auricular vessels, external jugular vein and posteromedial surface of the parotid gland.

Question 6

What’s the deep relations of the sternomastoid muscle?

Answer 6

Carotid sheath, lobe of thyroid, scalenus anterior muscle and phrenic nerve, intermediate tendon of omohyoid and transverse cervical and suprascapular arteries on it.
Eight muscles: 3 infra-hyoid (sternohyoid, sternothyroid and intermediate tendon of omohyoid), 3 muscles of the floor of posterior triangle and 2 other muscles: posterior belly of digastric and scalenus anterior.
Subclavian artery
Cervical plexus
Thoracic duct
Anterior jugular vein

Question 7

What covers the cervical plexus?

Answer 7

The internal jugular vein and the sternomastoid muscle.

Question 8

What’s the cervical plexus formed of?

Answer 8

Anterior rami of upper 4 cervical nerves.

Question 9

What are the muscular branches of the cervical plexus?

Answer 9

Phrenic nerve to diaphragm, descendens cervicalis to infrahyoid muscles except thyrohyoid, muscular branches: lateral series to sternomastoid, trapezius, scalenus medius and levator scapulae.
Medial series to rectus capitis anterior and lateralis and longus colli and longus capitis.

Question 10

What are the communicating branches of the cervical plexus?

Answer 10

Communicating branches to the last 3 cranial nerves.