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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    rior run almost directly downwards, while the fibres of the other portion radiate both forwards and backwards; these two portions in some measure decussate, or cross one another. Ine anterior fibres, which run furthest and lowest down, are tendinous at their insertion, while the posterior and shortest are fleshy. The use of the whole muscle is to raise the lower jaw ; and when it is brought forwards, the posterior and inner portion will assist in bringing it a little back: so that this muscle becomes a rotator, if the jaw°happens to be turned to the opposite side. We may observe that this muscle is intermixed with a number of tendinous portions, both at its origin and its insertion; which give rise to a greater number of fleshy fibres, and thereby add to the strength of the muscle. Of the Temporal Muscle. The temporal muscle is situated on the side of the head, above and a little before the ear. It is a flat and radiated muscle; broad and thin at its origin; narrow and thick at its insertion; and covered with a pretty strong fascia above the jugum. This fascia is fixed to the bones round the whole circumference of the origin of the muscle. Above, it is fixed to a smooth white line, which is observable upon the skull, extending from a little ridge on the lateral part of the os frontis, continued across the parietal bone, and making a turn towards the mammillary process. It is fixed below to the ridge where the zygomatic process begins, just above the meatus auditorius; then to the upper edge of the zygomatic process itself, and anteriorly to the os mala?. This adhesion above, before, and behind, describes, as it were, the cir- cumference of the origin of the temporal muscle. This muscle arises from all the bones of the side of the head that are within the line for insertion of the tendinous fascia, viz from the lower and lateral part of the parietal bone, from all the squa- mous portion of the temporal bone, from the lower and lateral part of the os frontis, from the temporal process of the os sphenoides, often from a process at the lower part of this surface (which portion, however, is often common to this muscle and the ptery- goideus externus), and from the posterior surface of the os mala?: outwardly, it arises from the inner surface of the jugum, and from the whole inner surface of the fascia. At this origin from the jugum it is not to be distinguished from the masseter, being there in fact one and the same muscle; and indeed the mas- seter is no more than a continuation of the same origin under the edge of the jugum, and might properly enough be reckoned the same, both as to its origin and insertion, and in some measure in its use also. The origin is principally fleshy, and the muscle passes from thence downwards and a little forwards, converging, and forming a thin middle tendon: after which the muscle runs downwards ou