Anterior Neck Triangles By Dr. Adel Sahib Al-Mayaly Head & Neck Surgery

Muscular triangle It is one of the anterior neck triangles that is found in the infrahyoid region. It is bounded by the superior belly of omohyoid m. superiorly, SCM inferiorly & mid line of neck anteriorly. It contains the infrahyoid muscles

Muscular Triangle Boundaries:- Superiorly;- superior belly of omohyoid m. Inferiorly:- anterior border of SCM Anteriorly:- midline of neck. Roof:- investing layer. Floor:- Infrahyoid muscle.

Contents of muscular triangle infrahyoid muscles 1- sternohyoid m. 2- omohyoid m. 3- sternohyoid m. 4- thyrohyoid m. They are supplied by Ansa cervicalis n( C 1,2,3) They depress the hyoid bone & eventually the larynx so that they narrow the upper esophageal opening.

Infrahyoid muscles

Ansa cervicalis is a loop of nerves that are part of the cervical plexus+ It lies superficial to the internal jugular vein in the carotid triangle. Its name means "handle of the neck" in Latin. Branches from the ansa cervicalis innervate most of the infrahyoid muscles

Roots of ansa cervicalis 1- Superior root:- (descendens hypoglossi). It is derived from anterior primary rami of C1 It supplies the thyrohyoid muscle & superior belly of omohyoid m.

Ansa cervicalis 2-The inferior root(C2,3) (descendens cervicalis) gives off branches to 1- inferior belly of omohyoid muscle 2- sternothyroid. 3- sternohyoid.

Hyoid Bone A horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the third cervical vertebra (C3). Unlike other bones; is only articulated to other bones by muscles or ligaments.

Attachments of hyoid Superior attachment Inferior attachments 1- Middle pharyngeal constrictor muscle 2-Hyoglossus muscle 3-Genioglossus 4-Intrinsic muscles of the tongue 5-Suprahyoid muscles 6-Digastric muscle 7-Stylohyoid muscle 8-Geniohyoid muscle 9-Mylohyoid muscle Inferior attachments Thyrohyoid muscle Omohyoid muscle Sternohyoid muscle

Submental triangle Boundaries;- is a division of the anterior triangle of the neck. Boundaries;- Medially: midline raphe of the neck Laterally: anterior belly of the two digastric muscles Posteriorly: hyoid bone Floor :- Mylohyoid muscle. Contents:- Submental L.N, Submental veins.

Contents of Submental triangle

Submandibular triangle Boundaries:- 1- anteriorly:- anterior belly of digastric m. 2- posteriorly:- posterior belly of digastric muscle. 3- superiorly:- body of mandible.

contents 1- Arteries:- Facial & lingual. 2- Nerves:- hypoglossal & nerve to mylohyoid. 3- Glands:- submandibular & its duct. 4- Submandibular L.Ns 5- Suprahyoid muscles.

Suprahyoid muscles

Lingual Artery. • Is the third branch ECA . • Origin: external carotid artery at the level of hyoid bone. • May give origin to the ascending pharyngeal artery or the facial artery. • Course: Ascends deep to the digastric and stylohyoid muscles against the lateral wall of the pharynx It Continues anteriorly until it plunges into the hyoglossus muscle

Facial (External Maxillary) Artery • Is the fourth branch. • Origin: anteriorly at the lower border of the digastric muscle beneath the angle of the mandible. • Course: ascends anterosuperiorly deep to the digastric and the stylohyoid muscles to traverse the sub mandibular triangle in contact with the glands' posterior surface . • Its cervical branches include 1-Ascending palatine 2-Tonsillar 3-Branches to the submandibular gland. 4-Submental branch to the mylohyoid muscle and adjacent tissue 5-Masticator branches

Hypoglossal Nerve (CN XII) Emerges from the skull through the hypoglossal (anterior condylar) canal in the occipital bone. Lies medial to the internal jugular vein and the internal carotid artery. Near its emergence from the skull, receives branches from the upper cervical nerve (C-1). These cervical fibers leave the nerve as the superior root of the ansa cervicalis. Innervates the muscles of the tongue.