Posterior Triangle of Neck: Boundaries and Contents

June 15, 2012 | By | Reply More

Posterior Triangle of Neck: Boundaries and Contents

Boundaries of posterior triangle

  • Apex: Union of the Sternocleidomastoid and the Trapezius muscles at the Superior Nuchal Line of the Occipital bone
  • Anterior: Posterior border of the Sternocleidomastoid
  • Posterior: Anterior border of the Trapezius
  • Base: Middle one third of the Clavicle

Subdivision of Posterior Triangle

  • Lateral region of the neck.
  • Subdivided into two smaller triangles.

–   Occipital triangle

–   Supraclavicular triangle

 The Occipital Triangle

  • Larger and more posteriorly placed.
  • Bounded by the omohyoid, trapezius, and sternocleidomastoid muscles.
  • Contains the external jugular vein, the accessory nerve, the brachial plexus, and some lymph nodes.

Supraclavicular Triangle

  • Also called omoclavicular and subclavian.
  • Bounded by the clavicle, omohyoid, and sternocleidomastoid muscles.
  • Contains part of the subclavian vein and artery as well as some lymph nodes.

Contents of posterior triangle


  • Inferior belly of omohyoid
  • Splenius capitis
  • Levator scapulae
  • Scalenus anterior
  • Scalenus medius
  • Scalenus posterior
  • Scalenus space is bounded by the scalenus anterior and medius and 1st  rib (The brachial plexus and subclavian artery pass through the space)


External jugular vein:

  • on the surface of the sternocleidomastoid,
  • piercing the investing layer of the cervical fascia,
  • terminating in the subclavian vein.

Subclavian vein:

  • being continuous with axillary v.,
  • running the Ant. to the scalenus Anterior,
  • uniting with internal jugular vein to form brachiocephalic vein at the posterior to the sternoclavicular joint

Subclavian artery:

  • the right a. from the brachiocephalic trunk, the left from the aorta arch;
  • Post. To the subclavian v.
  • Anteroinferior to the brachial plexus in scalenus space
  • Being changed for axillary a. at the lateral border of the 1st rib

Transverse cervical artery

  • from thyocervical trunk
  • superior to the clavicle
  • deep to the omohyoid
  • reaching the deep to the trapezius

Suprascapular artery

  • from thyrocervical trunk
  • Posterior to clavicle

3. Lymph nodes

Superficial cervical Lymph nodes

placed along the external jugular vein.

4. Nerves

Trace the course of nerves through the neck noting especially: the sensory and motor branches of the cervical and brachial plexuses, their course and distribution in the neck and their relationship to major bony, muscular, or vascular landmarks in the region.

Cervical Plexus

  • The cervical plexus is formed by ventral rami of C1-C4
  • Most branches are cutaneous nerves of the neck, ear, back of head, and shoulders
  • The most important nerve of this plexus is the phrenic nerve
  • The phrenic nerve is the major motor and sensory nerve of the diaphragm

Branches of cervical plexus

  • Lesser occipital nerve.
  • Greater auricular nerve.
  • Transverse nerve.
  • Supraclavicular nerve.
  • Phrenic nerve.

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Category: Anatomy, Medical

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