197812-19884 Author:Unknown Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: (if the jaw: the lower extremity of this muscle is super. ficial, and lies between the parotid and Bubmaxillary glands. Pterygoideds Externus is short and tri... more »angular, placed at the lower part of the temporal fossa, arises broad and fleshy from the outer side of the external pterygoid plate, from the crest on the great wing of the sphenoid, and from the back part of the tuberosity of the superior maxilla; the fibres pass outwards and backwards, nearly horizontal and converging, are inserted tendinous into the anterior and internal part of the neck of the lower jaw, and of the interarticular cartilage. Use, to draw forward the jaw and interarticular cartilage ; if only one act, it will turn the jaw to the opposite side, so as to triturate or grind the food. These muscles are the chief agents in producing dislocation of the jaw; when the month is widely opened their spasmodic action may suddenly draw the condyles forwards off the tubercles into the zygomatic fossae. The external pterygoid muscle lies in a transverse direction beneath the base of the cranium, and much further from the surfcce than the internal pterygoid, superior to which it lies ; it is internal, and inferior to the temporal muscle, and is also concealed by the masseter. As the external and internal pterygoid muscles arise so near each other, and thence pass in different directions to their insertion, the external going transversely, and the internal descending, they leave between them a triangular space, which contains a quantity of fat, a small portion of the parotid gland, the internal maxillary artery and vein, and the dental and gustatory branches of the inferior maxillary nerve. SECTION III. VESSELS AND NERVES OF THE FAC£. The arteries which are to be met with in the dissection of this region, are t...« less