Posterior Triangle

Posterior Triangle of the Neck

Information and Background:

As the dissection moves into the head and neck, it is important to understand the lymphatic drainage. You must know which structures drain to which sets of nodes as well as where those nodes drain as the flow returns to the vascular system.
The focus of the dissection will change from large gross structures to smaller and more delicate structures. Keeping this in mind during dissection will help to prevent the destruction of important structures.
Investigate the effects of scalene compression syndrome.
Understand the nerves emerging from and comprising the cervical plexus.

Dissection:
    1. Make an incision through skin from mastoid process to sternum following sternocleidomastoid. Make a second incision from the acromion process along the clavicle to the sternum. Reflect the skin toward the trapezius muscle
    2. Reflect platysma superiorly. The muscle is thin, take care not to destroy the cervical nerves and the external jugular vein which is directly below the muscle.
    3. Locate the external jugular vein which is directly on top of SCM. Clean off the muscle and the vein.
    4. Locate the cutaneous cervical nerves exiting the posterior edge of SCM.
        Lesser Occipital Nerve, Great Auricular Nerve, Transverse Cervical Nerve, and Supraclavicular Nerve
    5. Locate the accessory nerve traveling from the posterior superior edge of SCM down to the anterior inferior edge of trapezius.
    6. Locate and clean the inferior belly of omohyoid which is located several cm above the clavicle. Preserve the nerve to the muscle (branch from Ansa Cervicalis) which enters the deep surface.
    7. Locate the transverse cervical and suprascapular arteries.
    8. Locate the brachial plexus and the subclavian artery deep to inferior belly of omohyoid both of which exit between the anterior and middle scalene muscles. The dorsal scapular and suprascapular nerves from the root of the brachial plexus may be found.
    9. Locate the phrenic nerve running on top of the anterior scalene muscle.
   10. Clean remaining muscles found on the floor of the triangle.

Pictorial Atlas:
Skin Incision
Platysma Reflection
Superficial Triangle
Deep Triangle
Posterior Triangle Structures List