Anterior triangle of the neck
The anterior triangle is a region of the neck. Structure. The triangle is inverted with its apex inferior to its base which is under the chin. Investing fascia covers the roof of the triangle while visceral fascia covers the floor. Anatomy. Muscles: Nerve supply. 2 Bellies of Digastric Stylohyoid: by the facial nerve, by a branch from that to the posterior belly of digastric. Mylohyoid: by its own nerve, a branch of the inferior alveolar ( from the mandibular division of trigeminal nerve), which arises just before the parent nerve enters the mandibular foramen, pierces the  sphenomandibular ligament, and runs forward on the inferior surface of the mylohyoid, supplying it and the anterior belly of the digastric. Geniohyoid: by a branch from the hypoglossal nerve consisting of fibres from the C1 nerve. Sternohyoid, Omohyoid, Sternothyroid are supplied by Ansa cervicalis. Thyrohyoid: by a branch of hypoglossal nerve but the fibres are all 'hitch-hiking' from C1. Divisions. This space is subdivided into four smaller triangles by the Digastricus above, and the superior belly of the Omohyoideus. These smaller triangles are named: