Surgical anatomy for students / by A. Marmaduke Sheild.

  • Sheild, A. Marmaduke (Arthur Marmaduke)
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: Surgical anatomy for students / by A. Marmaduke Sheild. Source: Wellcome Collection.

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    and emerges at the stylo-mastoicl foramen. It is purely a motor nerve. Its great primary divisions are the temporo- facial and cervico-facial. The former holds sway over the muscles from the temple to the mouth, except the masseter and temporal. The latter supjjlies the muscles of the lower lip, with the platysma of the neck. The stylo-hyoid and posterior belly of the digastric are supplied by special branches. The facial nerve likewise supplies some of the muscles of the palate, though this has been lately disputed. Horsley and Beevor, on stimulating the cut end of the facial nerve within the cranium, observed that the palate remained motionless. They found that the levator palati was entirely supplied by the spinal accessory nerve. The account given of the nerve supply of this muscle in the text-books, is therefore probably erroneous. Suppose the facial nerve to be paralysed (Bell's Paralysis) by ear disease in the aqueduct of Fallopius, by a growth at the stylo-mastoid foramen, by division in an operation, or exposure of the face to a cold draught in railway traveUiug, all the muscles of expression on that side of the face will be paralysed, also the buccinator. The mouth wiU. be drawn to the opposite side, and the affected side of the face will be blank and expressionless. The eye will be open and staring, it is also often inflamed from the entrance of dust. The tears run over the cheek, and the inferior nares on the affected side are often dry, while the aperture of the nostril seems dimin- ished in size from paralysis of the nasal muscles. The patient cannot frown, smile, or knit the brows. He is unable to whistle, and, in mastication, the food collects between the affected cheek and the jaw, while saliva often trickles from the mouth. In course of time a curious phenomenon may occur. The mouth is drawn towards the paralysed side. There is a pathological reason for this circumstance. Paralysed muscles after a time shorten and contract, in consequence of interstitial fibrosis. The course of the facial nerve is repre- sented on the face by a line drawn from the front border of