Applied anatomy : the construction of the human body considered in relation to its functions, diseases and injuries / by Gwilym G. Davis.

  • Davis, Gwilym G. (Gwilym George), 1857-1918.
Date:
1934
Catalogue details

Licence: Public Domain Mark

Credit: Applied anatomy : the construction of the human body considered in relation to its functions, diseases and injuries / by Gwilym G. Davis. Source: Wellcome Collection.

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    regular in their course, one passing backward, low down, parallel to the zygoma, and another higher up in the direction of the parietal eminence. The branches of the meningeal artery nourish the bone as well as the dura, therefore if the dura is loosened from the bone, hemorrhage from these branches occurs. The most fre¬ quent site of middle meningeal hemorrhage is in the region of the pterion or temple. In extradural hemorrhage the artery may be torn low in the middle fossa where it lies in a groove in the hone, or over the cortex where it runs in the dura. The symptoms of extradural hemorrhage are quite typical. There is loss of con¬ sciousness usually followed by a lucid interval, after which there occurs headache, often convulsions, increasing stupor, and evidence of increasing intracranial pres- and—optic 3rd—oculomotor 4th—trochlear (pathetic) 1st—olfactory 5th—trigeminal (trifacial) 6th—abducent 7th—facial tory 9th—glossopharyngeal 10th—vagus (pneumogaatrlc) nth—spinal accessory 12th—hypoglossal Fig. 24.—Exit of cranial nerves at the base of the skull. sure. The symptoms are due to a spurting branch of the middle meningeal vessel. Extradural hemorrhage occurs in only about ten percent of cases of cranial trauma. It is not very common. Treatment may be by a decompression or by the elevation of a bone flap. In decompressing, the centre of the trephine is to be placed on an average of 4 cm. (1J/2 in.) behind the external angular process of the frontal bone, and on a level with the upper edge of the orbit or 4.5 cm. (i^4 in.) above the zygoma. If the artery is not sufficiently exposed more bone is to be removed by the rongeur forceps. It is in this region that epidural hemorrhages are apt to be extensive, be¬ cause the vessels torn are the largest; but epidural hemorrhage can also occur in the frontal region from the anterior branches and in the parietal, from the posterior branches. The advantage of subtemporal decompression is due to the anatomical position of the opening. The squamous portion of the temporal bone underlying the tem¬ poral muscle is the thinnest portion of the skull and is the area most frequently injured. The middle meningeal is exposed where it is torn or the temporal lobe /' . /