Posterior triangle of the neck

Question 1

List the boundaries of the posterior triangle.

Answer 1

Anterior border: Posterior border of sternocleidomastoid muscle.
Posterior border: anterior border of trapezius.
Inferior border: superior border of the clavicle.

Question 2

What innervates platysma?

Answer 2

Facial nerve

Question 3

What two other nerves are in contact with platysma?

Answer 3

Cutaneous nerves - supraclavicular and transvere cervical nerves in contact with deep surface.

Question 4

Where does the external jugular run and what does it pierce?

Answer 4

Begins posterior to angle of the mandible, crosses superficial surface of sternocleidomastoid. 3cm superior to the clavicle, external jugular then pierces investing layer of the deep cervical fascia (roof of triangle)

Question 5

What does the external jugular vein drain into?

Answer 5

subclavian vein.

Question 6

Skin of neck and posterior head are innervated by?

Answer 6

Cutaneous nerves of cervical plexus C1-4.

Enter midpoint of superficial fascia.

Question 7

Where do cervical nerves enter the posterior triangle ?

Answer 7

Midpoint of posterior border of the sternocleidomastoid.

Question 8

What are 4 nerves at erbs point?

Answer 8

C1-4 cutaneous branches 
lesser occipital nerve
great auricular nerve
transverse cervical nerve 
supraclavicular nerve

Question 9

Where is the accessory nerve found ?

Answer 9

Superior to midpoint of posterior border of sternocleidomastoid to the anterior border of trapezius. Lies deep to investing layer of the deep cervical fascia.