Muscular triangle

The inferior carotid triangle (or muscular triangle), is bounded, in front, by the median line of the neck from the hyoid bone to the sternum; behind, by the anterior margin of the sternocleidomastoid; above, by the superior belly of the omohyoid. It is covered by the integument, superficial fascia, platysma, and deep fascia, ramifying in which are some of the branches of the supraclavicular nerves. Beneath these superficial structures are the sternohyoid and sternothyroid, which, together with the anterior margin of the sternocleidomastoid, conceal the lower part of the common carotid artery. This vessel is enclosed within its sheath, together with the internal jugular vein and vagus nerve; (Wikipedia)