QS Study

Posterior triangle of the neck

It is a space on the side of the neck situated behind the sternomastoid muscle. The posterior triangle of the neck is an anatomical area located in the lateral aspect of the neck.


  • Anteriorly: Posterior border of sternocleidomastoid.
  • Posteriorly: an Anterior border of the trapezius.
  • Inferiorly or base: Middle 1/3 of the clavicle.
  • Apex: Lies on the superior nuchal line where the trapezius & sternocleidomastoid meet.
  • Roof: Formed by the skin, superficial fascia & the investing layer of deep cervical fascia. It’s created by the investing layer of the deep cervical fascia, extending between the sternocleidomastoid and trapezius muscles.

It is covered by the investing layer of fascia, and the floor is formed by the prevertebral fascia.

Posterior Triangle of Neck 1

Fig: the Posterior triangle of the neck

The superficial fascia contains: The superficial fascia overlying the roof includes platysma, external jugular and posterior jugular veins and cutaneous nerves and vessels.

  1. The platysma.
  2. The external jugular vein.
  3. Parts of the supraclavicular, great auricular & lesser occipital nerves.
  4. Unnamed arteris from occipital, transverse cervical & suprascapular arteries.
  5. Lymph vessels.


Formed by the prevertebral layer of deep cervical fascia covering the following muscles:

  1. Semispinalis capitis.
  2. Splenius capitis.
  3. Levator Scapulae.
  4. Scalenus posterior.
  5. Scalenus medius.
  6. Solent’s anterior.
  7. The 1st digitation of the serratus anterior.


(A) Nerves

  • The spinal accessory nerve.
  • Some cutaneous & muscular.
  • Branches from cervical plexus.
  • Upper parts of brachial plexus.

(B) Vessels

  • Transverse cervical vessels.
  • Subclavian vessels.
  • Suprascapular vessels.
  • Occipital artery.
  • External jugular vein ( Lower part).

(C) Lymph nodes:

  • Supra clavicular nodes.
  • Occipital nodes.
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