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.
- 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.
- 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
- 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
- from thyrocervical trunk
- Posterior to clavicle
placed along the external jugular vein.
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.
- 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.