hypoglossi

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.

VI. The Arteries. 3a. 3. The Triangles of the Neck 1918

Around the foramen magnum they form an intricate net-work which opens into the vertebral veins and is connected above with the occipital sinus, the basilar plexus, the condyloid emissary vein, and the rete canalis hypoglossi.

VII. The Veins. 3c. The Veins of the Upper Extremity and Thorax 1918

In the inferior part of the fossa the medial eminence assumes the form of a triangular area, the trigonum hypoglossi.

IX. Neurology. 4a. The Hind-brain or Rhombencephalon 1918

In front of the sheath of the common carotid is the ramus descendens hypoglossi.

VI. The Arteries. 3a. 3. The Triangles of the Neck 1918

Below the inferior fovea, and between the trigonum hypoglossi and the lower part of the area acustica is a triangular dark field, the ala cinerea, which corresponds to the sensory nucleus of the vagus and glossopharyngeal nerves.

IX. Neurology. 4a. The Hind-brain or Rhombencephalon 1918

The hypoglossal nucleus is derived from the base of the anterior column; in the lower closed part of the medulla oblongata it is situated on the ventrolateral aspect of the central canal; but in the upper part it approaches the rhomboid fossa, where it lies close to the middle line, under an eminence named the trigonum hypoglossi (Fig. 709).

IX. Neurology. 4a. The Hind-brain or Rhombencephalon 1918

This nucleus is about 2 cm. in length, and its upper part corresponds with the trigonum hypoglossi, or lower portion of the medial eminence of the rhomboid fossa (page 779).

IX. Neurology. 5l. The Hypoglossal Nerve 1918

The Descending Ramus (ramus descendens; descendens hypoglossi), long and slender, quits the hypoglossal where it turns around the occipital artery and descends in front of or in the sheath of the carotid vessels; it gives a branch to the superior belly of the Omohyoideus, and then joins the communicantes cervicales from the second and third cervical nerves; just below the middle of the neck, to form a loop, the ansa hypoglossi.

IX. Neurology. 5l. The Hypoglossal Nerve 1918

From the first two nerves the branch joins the hypoglossal trunk, runs with it some distance, and sends off a branch to the Thyreohyoideus; it then leaves the hypoglossal to form the descendens hypoglossi and unites with the communicantes cervicalis from the second and third cervical nerves to form the ansa hypoglossi from which nerves pass to the other Infrahyoid muscles.

IV. Myology. 5c. The Supra- and Infrahyoid Muscles 1918

Branches from the descendens hypoglossi and phrenic reach the investing capsule, but do not penetrate into the substance of the gland.

XI. Splanchnology. 4c. The Thymus 1918