__ The ciliary body (corpus ciliare) connects the chorioid to the circumference of 
the iris (Fig. 497), and presents the following three zones, viz: (w) the orbiculus 
ciliaris, (6) the ciliary processes, and (¢) the ciliary muscle. 
The orbiculus ciliaris forms a zone of about 4 mm in width immediately 
_ adjoining the chorioid, and exhibits numerous radially-arranged ridges. The ciliary 
_ processes (processus ciliares), about seventy in number, form a circle of radial thicken- 
ings, each of a somewhat triangular shape. The base of the triangle is directed 
forwards towards the , 
_ equator of the lens, while 
the apex is continuous 
_ behind with some three 
or four ridges of the WARE 
orbiculus ciliaris. They Anterior chamber 4 1th 
vary in size, the largest e a3 
having a length of 
2-51m. Thestructure of 4! 4 Sctleum 
_ the orbiculus ciliaris and <4 Fostex 
ciliary processes is similar 
to that of the chorioid,  Conjunctixz 
but the capillaries are Z 
larger and more tortuous, 
and there is no lamina 
choriocapillaris' The 
deep aspect of the ciliary 
is covered by 
two strata of columnar 
epithelium, the anterior 
layer of which is pig- 
mented; these two strata 
form a direct continua- 
tion forwardsof the retina Petichoricidal lymph space 
and constitute the pars 
ciliaris retine. This epi- 
thelium is invaginated to 
form more or less tubular 
glands, which may take 
a share in the secretion, 
_ of the aqueous humour. 
The ciliary muscle (m. 
a _ een seer Fic. 497.—Sucnos TaHroven Cuiser Becios or Exrzsix 
__ and consists of two sets of fibres—radial and circular (Fig. 497). The radial fibres 
(fibre meridionales, Briickei) spring from the corneo-scleral junction behind the 
_ eanal of Schlemm and from the ligamentum pectinatum iridis, and radiate back- 
wards, to be attached to the ciliary processes and orbiculus ciliaris: When they 
_ contract the chorioid is drawn forwards and the lens becomes more convex, owing 
to the relaxation of its suspensory ligament (see p. 693). The cirenlar fibres (fibre 
_ circulares, Miilleri) form a triangular zone behind the ligamentum pectinatum y 
iridis, close to the periphery of the iris, and also extend backwards under the radial 
_ fibres. Considerable individual differences are found as to the degree of develop- 
ment of these two portions of the ciliary muscle. The radial fibres are always more 
‘numerous than the circular fibres, the latter being absent or rudimentary in myopic 
eyes, but well developed, as a rule, in h etropic eyes. 
The iris forms a contractile diaphragm in front of the lens and is pierced a 
little to the nasal side of its centre by an almost circular aperture, the pupil 
(pupilla), which, during life, is continually varying in size in order to 
the amount of light admitted into the interior of the globe. It divides the space 
between the cornea and lens into two parts, which are filled by the aqueous humour. 
and named respectively the anterior and posterior chambers of the eyeball Its 
= 
naa 
- 
—ae 
ACNE GR yg 
AON, 
Ss . 
ee 
ees Dans is 
vie on Sdawsnastiivngy, . 
Pars Giliaris retime 
Oritsenlus 
eilzaris 
Lonule of Zan 
—— . 
