Surgical anatomy / by John A.C. Macewen.

  • Macewen, John A. C.
Date:
1910
Catalogue details

Licence: In copyright

Credit: Surgical anatomy / by John A.C. Macewen. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    Temporal Region.—Over the temporal region the aponeu- rosis of the occipito-frontahs becomes very attenuated, losmg itself gradually as it approaches the zygoma by numerous small insertions into the temporal fascia. It also sends some prolongations into the subcutaneous tissues, but in this region the aponeurosis is not nearly so intimately associated with the subcutaneous tissues as in the scalp proper. The temporal muscle takes origin from, and is covered m by, the temporal fascia, which arises from the temporal ridge and runs down to be inserted into the zygoma, spUtting as it does so to enclose branches of the temporal and orbital arteries, embedded in fat. The fascia is remarkably strong and dense, so as to be practically indistinguishable from bone on palpation. Were an abscess occurring in the temporal region, this fascia would tend to prevent its pointing locally, and would direct it'under the zygoma, whence it may extend even to the neck. The pericranium in this region is much more adherent than it is over the vault, and hence subpericranial hsematomas are very unlikely to occur. The bones composing the cranial vault are developed in membrane, possess few osteoblasts, and have but little healing power. Thus, after destruction of a portion of the vault, it is unusual to find repair by osseous tissue, the bone generally being replaced by fibrous tissue. Necrosis most often affects the frontal and parietal bones, and not infrequently the external table alone is affected. Extensive destruction of the anterior portion of the vault is sometimes due to syphilitic ulceration, the dura presenting at the bottom of the ulcer. Craniotabes is a condition met with in early life, affecting generally the parieto-occipital region, due to rickets or inherited syphihs, in which the bone becomes thin and parchment'-like. The inner table of the skull is thinner and more brittle than the outer, and in fractures or gun-shot wounds involving both tables is generally much more extensively shattered than the outer. In some cases where a rifle-bullet strikes the skull tangentially, cutting a groove in the external table, the inner, although apparently not directly imphcated, has been shat- tered over a considerable area and driven into the brain substance. Sometimes also, as the result of injury, the inner
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