he wound is comparatively
superficial, owing to the circumstance of the instrument having
encountered one or more parts of the hyo-laryngeal range; but woeful
chance sometimes directs the weapon horizontally through that membranous
interval between the thyroid and hyoid pieces, in which case, as also in
that where the laryngeal pieces persist permanently cartilaginous, the
resistance to the cutting instrument is much less.

The anatomical position of the parotid, H, Plate 3, and submaxillary
glands, W, Plate 4, is so important, that their extirpation, while in a
state of disease, will almost unavoidably concern other principal
structures. Whether the diseased parotid gland itself or a lymphatic
body lying in connexion with it, be the subject of operation, it seldom
happens that the temporo-maxillary branch of the external carotid, F,
escapes the knife. But an accident, much more liable to occur, and one
which produces a great inconvenience afterwards to the subject, is that
of dividing the portio-dura nerve, S, Plate 4, at its exit from the
stylo-mastoid foramen, the consequence being that almost all the muscles
of facial expression become paralyzed. The masseter, L, Plate 3,
pterygoid, buccinator, 15, Plate 4, and the facial fibres of the
platysma muscles, A O, Plate 3, still, however, preserve their power, as
these structures are innervated from a different source. The orbicularis
oculi muscle, which is principally supplied by the portio-dura nerve, is
paralyzed, though it still retains a partial power of contraction, owing
to the anatomical fact that some terminal twigs of the third or motor
pair of nerves of the orbit branch into this muscle.

The facial artery, V, and the facial vein, U, Plate 4, are in close
connexion with the submaxillary gland. Oftentimes they traverse the
substance of it. The lingual nerve and artery lie in some part of their
course immediately beneath the gland. The former two are generally
divided when the gland is excised; the latter two are liable to be
wounded in the same operation.

DESCRIPTION OF PLATES 3 & 4.

PLATE 3.

A A A. Subcutaneous platysma myoides muscle, lying on the face, neck,
and upper part of chest, and covering the structures contained
in the two surgical triangles of the neck.

B. Lip of the thyroid cartilage.

C. Clavicular attachment of the trapezius muscle.

D. Some lymphatic bodies of the post triangle.

E. External jugular vein.

F. Occi