Copy 1

The Dublin dissector or manual of anatomy. Comprising a description of the bones, muscles, vessels, nerves, and viscera ... / By Robert Harrison.

  • Robert Harrison
Date:
1838
Catalogue details

Licence: Public Domain Mark

Credit: The Dublin dissector or manual of anatomy. Comprising a description of the bones, muscles, vessels, nerves, and viscera ... / By Robert Harrison. Source: Wellcome Collection.

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    thick but pale fasciculus, situated under the cilie, at the edge of each eyelid. The palpebral and ciliary portions adhere more closely to the skin, and present an elliptical appearance, as the fibres from the upper and lower eye- lid intersect each other at the outer canthus, and adhere to the ligament of the external commissure. ‘The hori- zontal tendon of this muscle passes across the lachrymal sac a little above its centre, and a strong aponeurosis derived from its upper and lower edge, covers all the an- terior surface of the sac, and adheres to the margins of the bony gutter, in which it is lodged, where it becomes continuous with the periosteum. This tendon can be seen or felt through the integuments during life, particu- larly when the muscle is in action, or when the eyelids are drawn towards the temple. This muscle is of the mixed class: it sympathises with the eye ina remarkable and most useful manner ; it pos- sesses great irritability, particularly in children ; in puru- lent and strumous ophthalmia it is frequently spasmodi- cally contracted, and totally prevents the eye being seen: this affection is somewhat analogous to the spasmodic con- striction of the sphincter ani muscle. In the operation of opening the lachrymal sac, the incision should commence immediately below this ten- don, so as to avoid injuring it, and be carried obliquely downwards and outwards, to the extent of about half an inch. Separate the orbicularis from the occipito-frontalis over the internal half of the superciliary arch, the ten- sor tarsi and the corrugator supercilii muscles will be ex- posed. TENsor Tarst, arises tendinous from the posterior edge of the os unguis, where it joins the os planum, passes forwards between the conjunctiva and the expan- sion of the tendo oculi which covers the lachrymal sac, divides into two portions, which are inserted into the la- chrymal ducts, along which the fibres extend, nearly as far as the puncta: wse, to draw the puncta and eyelids into close contact with the eye, also to press the puncta towards the nose, to compress the Jachrymal sac, and to ‘force out the secretion from the follicles of the caruncula lachrymalis. .This muscle is also named Horner’s mus- cle from its discoverer, it will be better seen if the two
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