Occipital triangle

Occipital Triangle is an anatomical region located in the posterior aspect of the neck. It is one of the several triangles of the neck and is of clinical importance due to the structures it contains.

Anatomy

The Occipital Triangle is bounded by the sternocleidomastoid muscle anteriorly, the trapezius muscle posteriorly, and the inferior belly of the omohyoid muscle inferiorly. The floor of the triangle is formed by the splenius capitis, levator scapulae, and the middle and posterior scalene muscles. The roof is formed by the investing layer of the deep cervical fascia.

Contents

The Occipital Triangle contains several important structures including the Accessory nerve, Cervical plexus, and the Occipital artery.

Accessory Nerve

The Accessory nerve (Cranial nerve XI) passes diagonally across the triangle from the sternocleidomastoid towards the trapezius.

Cervical Plexus

The Cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which are located from C1 to C4 cervical segments in the neck. They are located laterally to the transverse processes between prevertebral muscles from the medial side and vertebral from lateral side.

Occipital Artery

The Occipital artery arises from the external carotid artery opposite the facial artery. Its path is below the posterior belly of digastric to the occipital region. This artery supplies blood to the back of the scalp and sterno-mastoid muscles, and deep muscles in the back and neck.

Clinical Significance

Knowledge of the Occipital Triangle is important in surgeries involving the neck. The Accessory nerve is at risk of injury during surgeries in this region. Damage to this nerve can result in shoulder drop.

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  Diagram of the occipital triangle
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  Muscles of the neck, showing the occipital triangle
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  Anatomy of the neck, highlighting the occipital triangle