QS Study

The anterior triangle is a region located at the front of the neck. The contents of the anterior triangle include muscles, nerves, arteries, veins, and lymph nodes. It is situated on every side of the neck and is a large triangular space, with its apex pointed downwards and base pointed upwards and in front of sternocleidomastoid.

The boundary of the Anterior triangle

Anteriorly: By the median plane, an Anterior belly of digastric muscle.

Posteriorly: By the sternocleidomastoid muscle. Posterior belly of the digastric muscle, supplemented by stylohyoid muscle.

Superiorly: By the base of the mandible and by a line joining the angle of the mandible to the mastoid process. It’s created by the base of the mandible and imaginary line joining the angle of the mandible to the mastoid process.

Apex: Lies above the manubrium sterni. It’s created by the intermediate tendon of the digastric muscle, being bound down to hyoid bone by a fascial sling originated from the investing layer of deep cervical fascia.

Boundary and Contents of Anterior Triangle 1

Fig: Boundary and Contents of Anterior Triangle

The content of the anterior triangle

(A) Muscles:

(i) suprahyoid muscles:

  • Digastric.
  • Stylohyoid.
  • Mylohyoid.
  • Geniohyoid.

(ii) Infrahyoid muscles:

  • Sternohyoid.
  • Sternothyroid.
  • Thyrohyoid.
  • Omohyoid.

(B) Vessels:

  • Common carotid artery.
  • External carotid artery.
  • Internal carotid artery.
  • Internal jugular vein.

(C) Nerves:

  • The spinal accessory nerves.
  • The hypoglossal nerve.
  • Sympathetic trunk.

(D) Carotid sheath & its contents: It’s a facial sheath which encloses internal jugular vein and internal and common carotid arteries. It is located posterior to the sternocleidomastoid muscle and is a part of the deep cervical fascia of the neck. Contents of the carotid sheath:

  • Common carotid artery
  • Internal jugular vein
  • Internal carotid artery
  • Vagus nerve.

(E) Few deep cervical groups of the lymph node.

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