84 
and continvation with each other of these two 
portions of the membrane. It is by this conti- 
nuity that the eyelids and eyeball are held in 
connexion, hence the name conjunctiva, and 
that the orbit is closed in and cut off from 
all communication with the space between the 
eyeball and eyelids. - 
The space between the eyelids and eyeball we 
shall distinguish by the name of oculo-palpebral 
€ of the conjunctiva, a name, the necessity 
or which appears from this, that in common 
language, when it is said a foreign body has 
got into the eye, it is only meant that it has got 
into the oculo-palpebral space of the con- 
Junctiva. The propriety of the name moreover 
will become more evident when the space in 
Serpents and Geckoes comes under considera- 
tion, for in them it is a closed cavity, (in ser- 
pents already designated by Jules Cloquet* 
oculo-palpebral sac of the conjunttiva,) re- 
ceiving the lacrymal secretion and communi- 
cating with the exterior only by the connexion 
it has with the nose through the nasal duct. 
What are called the superior and inferior 
palpebral sinuses of the conjunctiva are those 
parts of the oculo-palpebral space under the 
upper and lower eyelids respectively, where 
the ocular and paipebral portions of the con- 
junctiva are reflected and continued into each 
other, forming a cul-de-sac. The conjunctiva 
is here loosely attached to the subjacent cellular 
and adipose tissue, &c. of the orbit, and forms 
folds constantly varying with the motions of the 
eyeball and eyelids. The superior palpebral 
sinus of the conjunctiva is deeper than the 
lower, the reflection of the conjunctiva from the 
eyelids upon the eyeball being when the eyelids 
are passively closed: above, at the distance of 
about seven-tenths of an inch from the margin 
of the upper eyelid, and below, at about three- 
tenths of an inch from the margin of the lower. 
The cul-de-sac formed by the reflection of the 
conjunctiva does not lie very deep within the 
outer canthus, speaking in reference to it alone, 
though as near the edge of the orbit as above or 
below. 
The looseness of the folds formed by the 
conjunctiva at the upper and lower palpebral 
sinuses and within the outer canthus, together 
with the peculiar nature of its disposition at 
the inner canthus, presently to be noticed, allows 
of the free motions of the eyeball in all direc- 
tions. These folds may be readily seen on 
everting either eyelid, as also the continuity of 
the conjunctiva from the eyelid to the eyeball 
by requesting the person to look upwards, if it 
is the lower eyelid which is everted, downwards 
in the contrary case. 
In operations on the eyeball when the eyelids 
are held apart unskilfully, the folds are thrust 
out between the eyelids by the action of the 
orbicularis muscle, so that they almost bury 
the front of the eyeball and consequently im- 
pede the operator. 
By long-continued catarrhal ophthalmia and 
the abuse of blue stone and similar escharotics, 
* Memoire sur |’existence et la disposition des 
yoies lacrymales dans les serpens. Peris, 1821. 
LACRYMAL ORGANS. 
the conjunctiva is apt to become contracted an 
thickened, and to a i at the same time 
callous articular su In such cases th 
contraction tells very much upon the looser 
of the folds of the conjunctiva at the upper at 
lower palpebral sinuses, which may indeed 
said to be obliterated. The consequence 
this is great restriction in all the movements 
the eyeball. 
Foreign bodies which may have ente 
oculo-palpebral space sometimes get lod 
in Shasal bral posal of the conjunet 
especially the upper, and may be retained th 
for a length of time without causing much 
any irritation, the conjunctiva bei re 
loose and the adjacent cellular adi 
tissue of the orbit so soft that the body is - 
much pressed upon by the opposing surfac 
The contrary is the case when the foreign bo 
lies between the eyeball and the firm part 
the eyelid, for here its irritation excites t 
orbicularis muscle to stronger action wh 
serves but to aggravate the distress. 
Disposition of the conjunctiva at the inn 
canthus.—Under this head falls to be co 
dered the semilunar fold, the notice of whi 
it will be advantageous to premise by a deseri 
tion of the lacrymal caruncle. In consequen 
of the prolongation of the palpebral fissure 
the inner canthus into a secon one, | 
lacrymal caruncle and semilunar fold are $ 
exposed that their external con ion ¢ 
be readily and indeed best studied in the liv 
eye. ; ‘ 
“taal caruncle, caruncula la li 
Fr. La caroncule lacrymale. Ital. La caru 
cula lagrimale. Germ. Die Thranenkarunk 
This is a small reddish yellow eminence haviz 
a slightly tuberculated surface, beset with ve 
delicate scarcely visible hairs. It is situate 
as has been said, within the secon fissu 
of the inner canthus, and inclosed between t 
two slips of the tendo palpebrarum. To 
the lacrymal caruncle in its whole extent, it; 
necessary to evert slightly the lower eyeli 
when it 1s observed running into a point dow 
wards and outwards. The lacrymal carul 
consists of a mass of loose fibro-cartilagino: 
tissue, similar to that of the tarsal cartilages, 
which are imbedded follicles, secreting a fit 
of the same nature as that of the Meibomiz 
glands, and pouring it out by twelve or fif 
excretory orifices on its $ which is — 
vested by the conjunctiva. Anciently the 
crymal caruncle was thought to be the secret 
organ of the tears, and the lacrymal points 
excretory orifices. 1a 
Semilunar fold, plica semilunaris. 
repli semilunaire. Ital. La piega 
Germ. Die halbmondformigen Failte. In pass 
from the caruncle to the eyeball, the conjune 
forms a vertical semilunar fold which enclo 
at its free edge a minute cartilage of a na 
similar to the tarsal cartilages. This part 
the conjunctiva is distinguished from the 
portion by its reddish colour and greater th 
ness, indeed it resembles more the palpe 
conjunctiva than the ocular. The concavit 
the crescent, which is also the free edge of 7 
oo 
a 
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(i 
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