Henry Gray (18251861). Anatomy of the Human Body. 1918.
In front of the sheath are a few descending filaments from the ansa hypoglossi; behind the sheath are the inferior thyroid artery, the recurrent nerve, and the sympathetic trunk; and on its medial side, the esophagus, the trachea, the thyroid gland, and the lower part of the larynx. By cutting into the upper part of this space, and slightly displacing the Sternocleidomastoideus, the common carotid artery may be tied below the Omohyoideus.
The Superior Carotid, or Carotid Triangle, is bounded, behind by the Sternocleidomastoideus; below, by the superior belly of the Omohyoideus; and above, by the Stylohyoideus and the posterior belly of the Digastricus. It is covered by the integument, superficial fascia, Platysma and deep fascia; ramifying in which are branches of the facial and cutaneous cervical nerves. Its floor is formed by parts of the Thyrohyoideus, Hyoglossus, and the Constrictores pharyngis medius and inferior. This space when dissected is seen to contain the upper part of the common carotid artery, which bifurcates opposite the upper border of the thyroid cartilage into the external and internal carotid. These vessels are somewhat concealed from view by the anterior margin of the Sternocleidomastoideus, which overlaps them. The external and internal carotids lie side by side, the external being the more anterior of the two. The following branches of the external carotid are also met with in this space: the superior thyroid, running forward and downward; the lingual, directly forward; the external maxillary, forward and upward; the occipital, backward; and the ascending pharyngeal, directly upward on the medial side of the internal carotid. The veins met with are: the internal jugular, which lies on the lateral side of the common and internal carotid arteries; and veins corresponding to the above-mentioned branches of the external carotidviz., the superior thyroid, the lingual, common facial, ascending pharyngeal, and sometimes the occipitalall of which end in the internal jugular. The nerves in this space are the following. In front of the sheath of the common carotid is the ramus descendens hypoglossi. The hypoglossal nerve crosses both the internal and external carotids above, curving around the origin of the occipital artery. Within the sheath, between the artery and vein, and behind both, is the vagus nerve; behind the sheath, the sympathetic trunk. On the lateral side of the vessels, the accessory nerve runs for a short distance before it pierces the Sternocleidomastoideus; and on the medial side of the external carotid, just below the hyoid bone, may be seen the internal branch of the superior laryngeal nerve; and, still more inferiorly, the external branch of the same nerve. The upper portion of the larynx and lower portion of the pharynx are also found in the front part of this space.
The Submaxillary or Digastric Triangle corresponds to the region of the neck immediately beneath the body of the mandible. It is bounded, above, by the lower border of the body of the mandible, and a line drawn from its angle to the mastoid process; below, by the posterior belly of the Digastricus and the Stylohyoideus; in front, by the anterior belly of the Digastricus. It is covered by the integument, superficial fascia, Platysma, and deep fascia, ramifying in which are branches of the facial nerve and ascending filaments of the cutaneous cervical nerve. Its floor is formed by the Mylohyoideus, Hyoglossus, and Constrictor pharyngis superior. It is divided into an anterior and a posterior part by the stylomandibular ligament. The anterior part contains the submaxillary gland, superficial to which is the anterior facial vein, while imbedded in the gland is the external maxillary artery and its glandular branches; beneath the gland, on the surface of the Mylohyoideus, are the submental artery and the mylohyoid artery and nerve. The posterior part of this triangle contains the external carotid artery, ascending deeply in the substance of the parotid gland; this vessel lies here in front of, and superficial to, the internal carotid, being crossed by the facial nerve, and gives off in its course the posterior auricular, superficial temporal, and internal maxillary branches: more deeply are the internal carotid, the internal jugular vein, and the