Surgical anatomy for students / by A. Marmaduke Sheild.

  • Sheild, A. Marmaduke (Arthur Marmaduke)
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: Surgical anatomy for students / by A. Marmaduke Sheild. Source: Wellcome Collection.

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    and no reflex obtained on touching it, in cases of general in- sensibility, the condition of the patient is critical. If such a condition is found in the cornea in cases of cerebral haemorrhage, meningitis, abscess, and the like, death is not far off. In the administration of anaesthetics, when the pupil is dilated and reflex action abolished, the agent has probably heen pushed to the limit of prudenct;. Vessels.—The ophthalmic artery is one of the terminal branches of the internal carotid. It passes along the outer wall of the cavernous sinus. After fractures of the anterior fossa of the base of the skull, a communication sometimes takes place between the artery and sinus, and this leads to arterio- venous aneurism of the orbit. The artery enters the orbit through the optic foramen, and divides into two main sets of branches—those to the orbital tissues, ethmoidal, muscular, lachrymal, palpebral, frontal, and nasal; those to the eyeball itself, the anterior, long and short ciliary, and the central artery of the retina. The anterior ciliary arteries are derived from the muscular and lachrymal branches of the ophthalmic, and minute branches of them form a vascular ring round the margin of the cornea, beneath the conjunctiva. The vessels then pierce the sclerotic and join the external vascular circle of the iris. This pericorneal, subconjunctival, vascular zone, formed by twigs of the anterior ciliary vessels, is not visible in health, but in iritis, glaucoma, and especially inflammation of the ciliary body, the deep congestion causes these vessels to be engorged with blood, and the well-known salmon-coloured zone appears round the margin of the cornea. These little vessels are then not easily emptied by pressure with the finger, as is the case with the conjunctival arteries. If there is one important fact in the surgical anatomy of the eye, it is a consideration of the anterior ciliary arteries. A well-informed practitioner should look upon a ciliary zone of congestion in a case of eye disease as a symptom worthy of the closest attention. The posterior group of ciliary arteries pierce the sclerotic