

THE CONJUNCTIVA. 



823 



The skin covering the eyelids is thin and delicate, and is continuous, at their 

 margins, with their conjunctival lining. It contains numerous small sudoriferous 

 glands and fine hairs, the' latter being provided with sebaceous follicles. Branched 

 pigment cells are 



present in the _^jjjjjjg^. f 



cutis, and 

 ment exists 



Pig- 

 also 



Superior palpebral 

 ligament 



lacrimal nerve 



Superior tarsus 



Raphe palpebralis 

 lateralis 



Inferior palpebral 

 ligament 



Supra-orbital nerve 

 Supra-trochlear nerve 

 Superciliary arch 



Infra-trochlear nerve 



Lacrimal sac 



Ligamentum palpe- 

 brale mediale 



Inferior tarsus 



FlG. 



Infra-orbital nerv 



.DISSECTION OF THE .RIGHT EYELID. The orbicularis oculi has been 

 completely removed. 



Tendon of levator 

 in the deep layers palpebrse superior!* 



of the epidermis. 

 The subcutaneous 



tissue iS loose and M pebl branch of 



devoid of fat, and 

 in it are found 

 the fibres of the 

 orbicularis oculi 

 muscle a small 

 separate bundle 

 of which, termed 

 the muscle of 

 Riolan, occupies 

 the margin of the 

 lids behind the 

 eyelashes. 



The glandulae 

 tarsales(O.T.Mei- 

 bomian glands) are 



elongated sebaceous glands with numerous lateral offshoots ; they are embedded 

 in the tarsi and are filled with cubical epithelium. There are from twenty-five to 

 thirty in the superior eyelid, and from twenty to twenty-five in the inferior ; they 

 open by small ducts, about 1 mm. in length, along the lid margins, behind the 

 eyelashes ; the ducts are lined with stratified epithelium, placed on a basement 

 membrane. Between the eyelashes and the muscle of Eiolan are two or three 

 rows of modified sudoriferous glands, termed the glands of Moll. 



H. Miiller described a layer of non -striped muscle in each lid : in the superior extending from 

 the tendon of the levator palpebrse superioris to the upper tarsus, and in the inferior connecting 

 the inferior tarsus with the inferior oblique muscle. 



The eyelashes are curved, silky hairs which project from the free margins of 

 the lids ; in the upper lid they are longer and more numerous than in the lower, 

 and are curved upwards, while those of the lower lid are bent downwards. 



Conjunctiva. The conjunctiva is the mucous membrane which lines the 

 eyelids, and is continued, from them, on to the front of the bulb of the eye. 

 The part on the eyelids is termed the tunica conjunctiva palpebrarum, that on the 

 bulb of the eye the tunica conjunctiva bulbi ; the lines of reflection of fhe membrane 

 from the eyelids to the bulb are known as the superior and inferior conjunctival 

 fornices. The conjunctiva palpebrarum is intimately adherent to the tarsi and 

 presents numerous papillae. It is covered with a layer of columnar epithelial cells, 

 beneath the bases of which are small flattened cells ; near the fornices a number 

 of acino-tubular glands, much more plentiful in the upper than in the lower eyelid, 

 open on its free surface. The conjunctiva bulbi is thinner than the conjunctiva 

 palpebrarum, and is loosely attached to the sclera by submucous tissue. The 

 plica semilunaris conjunctive has already been referred to (p. 821). On the cornea 

 the conjunctiva is represented merely by the epithelium corneae (p. 809). 



Vessels and Nerves. The chief arteries of the eyelids are the superior and inferior palpe- 

 bral branches of the ophthalmic, which pierce the septum orbitale above and below the medial 

 palpebral ligament, and run laterally in the corresponding lid near its free margin. On reaching 

 the region of the lateral palpebral commissure they anastomose with each other and with twigs 

 from the lacrimal, superficial temporal, and transverse facial arteries, and in this way an arch 

 is formed in each lid. Secondary smaller arches are found, one above the primary arch in the 

 upper lid, and another below that of the lower lid, while the upper lid receives branches also 



53 c 



