Ellis's demonstrations of anatomy : being a guide to the knowledge of the human body by dissection / by George Viner Ellis.

  • Ellis, George Viner, 1812-1900.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Ellis's demonstrations of anatomy : being a guide to the knowledge of the human body by dissection / by George Viner Ellis. Source: Wellcome Collection.

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    to tlie sides. Tlie cilia of tlie two lids are convex towards one another, and cross wlien the lids are shut, piitrin^ Structure of the Eyelids. Each lid consists fundamentally eyelids. of a fibrous plate attached to the bone by ligaments. Superficial to this framework are the integuments with a layer of fibres of the orbicularis palpebrarum, and beneath it the mucous lining of the conjunctiva. The upper lid includes also the tendon of the levator pal])ebra3. Vessels and nerves are contained in the lids. Dissect lids. Dissection. The student may examine the structure of the lids on the left side, on which the muscles are dissected. The bit of tow or wool may remain beneath the lids ; and the palpebral part of the orbicularis muscle is to l)ethi'own inwards by an incision around the margin of the orbit. In raising the muscle care must be taken of the thin membranous palpebral fascia beneath, and of vessels and nerves of the lid. Layer of Orbicularis palpehrarum. The palpebral fibres of this muscle oi icu.uis. ^Q^^-^ p^^jg layer which reaches the free edge of the eyelids (p. 23). A thin stratum of areolar tissue without fat unites the muscle with the skin. i\ ^'^ '^^^^ palpebral fascia is a thin fibrous layer, which is continued from the margin of the orbit to join the anterior surface of the fibrous tarsal plate. At the inner part of the orbit the ligament is thin and loose, but at the outer part it is somewhat thicker and strongei'. A fibrous The fibroiis plates (tarsi), one for each eyelid, are elongated ilart^of tiifT transversely, and give strength to the lids. Each is fixed internally ^'•^ '• and externally by fibrous bands—the tarsal or palpebral ligaments, to the margin of the orbit. The border corresponding with the edge of the lid is free, and thicker than the rest of the plate. On the deep surface each tarsus is lined by the conjunctiva, dififerenoein The tarsi are not alike in the two lids. In the upper eyelid, the tA\() lids, ^^jjgj.g ^jjg fibrous plate is larger, it is crescentic in shape, and is nearly half an inch wide in the centre ; and to its fore part the tendon of the levator palpebrae is attached. In the lower lid the tarsus is a narrow band, al)out two lines broad, with nearly straight borders. Ligaments The internal tarsal lujainent (tendo pali)ebrarum) is a small fibrous attach tarsal band at the inner side of the orbit, which serves to fix the lids, and is plates. attached to the anterior margin of the lachrymal groove in the upper jaw. It is about a quarter of an inch long, and divides into two processes, which are united with the tarsal plates, one to each. This ligament crosses the lachrymal sac, behind which it sends a fibrous expansion ; and the fleshy fibres of the orbicularis palpebrarum arise from it. The external tarsal ligament is a much weaker band uniting the tarsi to the malar bone. Sebaceous The Meibomian or tarsal glands are embedded in the substance of u es in u . ^j^^ tarsal plates, and can be readily seen through the conjunctiva on the posterior surface of the lids. They extend, parallel to one another, from the free towards the opposite margin of the tarsus ; and their number is about thirty in the upper, and twenty in the