Areas - Posterior Triangle

Question 1

Where is it located?

Answer 1

The lateral aspect of the neck.

Question 2

Borders

Answer 2

Anterior - posterior border of the sternocleidomastoid

Posterior - anterior border of the trapezius

Inferior - middle 1/3 of the clavicle

Floor - prevertebral fascia

The posterior triangle is covered by investing layer of fascia.

Question 3

Contents?

Answer 3

Muscles:

1) Omohyoid (inferior belly) - the muscle enters the anterior triangle of the neck.
2) Vertebral muscles covered by prevertebral fascia (form the floor of the posterior triangle):
i) Spenius capitus
ii) Levator scapulae
iii) Anterior, middle and posteiror scalenes

Vasculature:

1) External jugular vein (formed by the retromandibular and posterior auricular veins). It enters the posterior triangle after passing the sternocleidomastoid. It then pierces the investing fascia and then empties into the subclavian.
2) Subclavian vein - often a point of access to venous system, via a central catheter.
3) Transverse cervical vein
4) Suprascapular vein
5) Distal subclavian artery than then becomes the axillary artery

Nerves

1) Accessory nerve - exits the cranial cavity, descends the neck, innervates the sternocleidomastoid, enters the posterior triangle in an oblique, inferoposterior direction, within the investing fascia. Superficial in the posterior triangle, leaving it vulnerable to injury.
2) Cervical plexus - forms within the muscles of the floor of the muscular triangle.

Answer 4

Relatively superficial course down the neck, leaving

Question 5

Subdivison - subclavian triangle

Answer 5

Distal subclavian runs in this triangle.

Omohyoid subdivides the posterior triangle.