260 SPECIAL ANATOMY. 



present. The free borders unite together, and form towards the 

 temples the external acute angle, commissura externa s. canihus 

 minor, which leads into a depression (of the conjunctiva?) ; towards 

 the nose (at the posterior border tf proc. ascendens maxilL super. .), 

 the internal rounded and wider angle, commissura internet s. can- 

 thus major. The superior eyelid is deeper than the inferior. 



a. The cartilages of the eyelids, tarsi, tarsal cartilages, are thin fibro-car- 

 tilaginous plates, which are placed towards the free border of the eyelids ; the 

 superior four, the inferior two lines, deep. Their anterior convex surface is 

 covered by m. orbicularis ; the posterior is firmly united with the conjunc- 

 tiva ; the free border is thick, the attached thin, in the superior eyelid convex 

 (here is affixed the m. levator palpebr. super.), and it continues into a fibrous 

 membrane, which externally, very strong at the basis orbitce, internally loses 

 itself in uniting tissue. 



The two tarsi do not reach to the angles of the eye, but become united to 

 them by the tarsal ligaments : 



Lig. palpebrale internum, a flat ligament, with its surfaces directed up- 

 wards and downwards, its borders forwards and backwards, which 

 passes away transversely inwards, before the lacrymal sac, to the 

 place where the frontal and superior maxillary bones (proc. frontalis.) 

 unite together ; and 



Lig. palpebrale externum, which passes off from the external extremity 

 of the tarsi (in a forked manner) protected by fibrous tissue, passes to 

 the proc. frontal, of the malar bone inside the orbit, and is attached to 

 its external angle. 



b. The external skin of the eyelids is thin, rather transparent, attached by 

 loose but fatless uniting tissue to the pale internal portion of m. orbicularis, 

 connected firmly with the tarsi, and passes over on the free border of the 

 eyelids into 



c. The uniting membrane of the eyelids, conjunctiva palpebrarum. It is a 

 soft, mucous membrane, covered with epithelium, provided with nerves and 

 vessels, which covers the free border and the posterior surface of the eyelids, 

 is reflected at the margins of the orbits from the lids upon the globe, forms 

 at the external angle of the eye a depression, at the internal (where is the 

 so-called lacus lacrymalis) a semilunar fold, concave towards the temples ; this 

 is, plica semilunar is (memb. nictitans, of animals). On the globe of the eye, 

 the anterior third of which it covers, the conjunctiva is only loosely connected 

 with the sclerotica, but the more intimately with the cornea. It enters into 

 the lacrymal canals at the puncta, and lines them. 



Vessels and nerves of the eyelids. Artt. palpebrales (interna et externa) are 

 branches of art. ophthalmica, temporalis, infraorbitalis andfacialis; they form 

 an arcus palpebralis (s. tarseus) superior and inferior. The veins of the same 

 name open into Vv. angularis and temporalis (facial, anter. and posterior). 

 Conjunct, palpebrar. is plentifully supplied with bloodvessels, less so the conj. 

 scleroticce, not at all the conj. corneas, in which Arnold has found Lymphatics. 



