Treatise on the natural history and diseases of the human teeth : explaining their structure, use, formation, growth, and diseases, in two parts / by John Hunter ; with notes by Thomas Bell.

  • Hunter, John, 1728-1793.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Treatise on the natural history and diseases of the human teeth : explaining their structure, use, formation, growth, and diseases, in two parts / by John Hunter ; with notes by Thomas Bell. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    pterygoid process of the sphenoid bone, excepting a little bit of the root at the posterior edge; and towards the lower part it arises a little from the inner surface of that ala. The thin portion arises from a ridge of the sphenoid that is continued from the process towards the temple, just behind the foramen lacerum informs, which terminates in a little protuberance. This origin is sometimes wanting, and in that case the temporal muscle arises from that protuberance ; and very often this origin is common to both. These two origins of this muscle are sometimes so much separated as to make it a biceps. From these origins the muscle passes outwards and a little back- wards, converging ; that is, the superior fibres passing outwards and backwards, and a little downwards; while the inferior or larger portion of it passes a little upward. It is inserted, tendinous and fleshy, into a depression on the an- terior part of the condyle and neck of the lower jaw, upon the inside of that ridge which is continued from the coronoid process; a little portion is likewise inserted into the anterior part of the moveable cartilage of the joint. When this muscle acts singly, it is a rotator; for it brings the condyle of the jaw forwards, and likewise the moveable cartilage, which throws the chin to the opposite side; but if it acts in con- junction with its fellow of the opposite side, instead of being turned to one side, the whole jaw is brought forwards, and thus these counteract the temporal, &c. These two muscles generally act alternately; and when they do so, one acts at the time of depression, the other at the time of elevation ; so that these muscles act both when the lower jaw is raised and when it is depressed ; although they do not assist in this act. Of the Superior Digastric Muscle. The digastricus is situated immediately under and a little upon the inside of the lower jaw, and exterior to the fauces, extending from the mastoid process to the chin, nearly along the angle made by the neck and chin, or face. The name of this muscle expresses its general shape, as it has two fleshy bellies, and of course a middle tendon. Yet some of its anterior belly does not arise from the tendon of the posterior, but from the fascia which binds it to the os hyoides. These two fleshy bellies do not run in the same line, but form an angle, just where the tendon runs into the anterior belly; so that this tendon seems rather to belong to the posterior, which is the thickest and longest. This muscle arises from the sulcus made by the inside of the mastoid process, and a ridge upon the temporal bone, where it is united with the os occipitis. The extent of this origin is about an inch; it is fleshy upon its outer part, viz. that from the mastoid process, and tendinous on the inside from the ridge. From its