The American encyclopedia and dictionary of ophthalmology Edited by Casey AWood, assisted by a large staff of collaborators . e; k, Ca^alm sellse; 1, Hiatussemilunaris; m, Twine in nasal duct; n, Additional orifice of antrum of High-more; p, Middle turbinal (cut); q, Middle meatus; r, Inferior turbinal; s,Inferior meatus; t, Orifice of Eustachian tube. The epithelium is ciliated. The direction of the nasal duct is down-ward, outward, and backward; it is enclosed in a canal formed by thelachrymal, superior maxillary, and inferior turbinate bones. The mucous membrane lining the sac and the nasal
The American encyclopedia and dictionary of ophthalmology Edited by Casey AWood, assisted by a large staff of collaborators . e; k, Ca^alm sellse; 1, Hiatussemilunaris; m, Twine in nasal duct; n, Additional orifice of antrum of High-more; p, Middle turbinal (cut); q, Middle meatus; r, Inferior turbinal; s,Inferior meatus; t, Orifice of Eustachian tube. The epithelium is ciliated. The direction of the nasal duct is down-ward, outward, and backward; it is enclosed in a canal formed by thelachrymal, superior maxillary, and inferior turbinate bones. The mucous membrane lining the sac and the nasal duct is attachedto the surrounding periosteum by loose areolar tissue which supportsa rich venous plexus. As a congenital anomaly (q. v.) the puncta lachrymalia or thecanaliculi may be double, or may be absent altogether. ANATOMY (GROSS) OF THE HUMAN EYE 353 The tears are drawn into the sac by suction, the motor power bft-ing supplied by the tensor tarsi, or Horners muscle. This is a small,thin muscle about 6 lines in length, and 3 lines in width; it lies be-hind the ligamentum palpebrie mediale near the inner Muscle of Horner, a, (After Poirier and Charpj.) Spiral fibres of this muscle surround the canaliculi; they compressthe tubules many times during the act of winking, thus sucking thesecretion through the puncta, which are closely applied to the sur-face of the eyeball. In this way, corneal and conjunctival debris—epithelium, microbes, mucus, tears, dust, etc.,—is scraped off thewhole globar surface and pushed toward the lachrymal outlet, thecleansing action of Horners muscle being kept up as long as neces-sary. Tears and other fluids may to some extent collect in the lach- 3o4 ANATOMY (GROSS) OF THE HUMAN EYE rymal sac before they percolate through the nasal duct into theinferior meatus. The conjunctiva, a most important mucous membrane, joins, as
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectophthalmology, bookye
