The document describes the triangles of the neck. It discusses the anterior and posterior triangles, which are divided by the sternocleidomastoid muscle. The posterior triangle contains nerves like the spinal accessory nerve and brachial plexus. It is further divided by the omohyoid muscle into the supraclavicular and occipital triangles. The anterior triangle contains the carotid vessels and is divided into the submental, submandibular, carotid, and muscular triangles. Both triangles contain important muscles and nerves.