28 LABORATORY OUTLINE OF NEUROLOGY 



front of the lens and behind the cornea is filled with aqueous 

 humor. The choroid coat is extended in front of the lens to 

 form the iris. 



14. Look up the structure of the human eye (see Section 

 135) and compare with that of the dogfish. Note the dif- 

 ference in the shape of the lens in the two cases. In mammals 

 the suspensory ligament is attached to a muscular ridge, the 

 ciliary process, whose ciliary muscles control the accom- 

 modation of the lens. In the dogfish the ciliary muscles 

 are feebly developed and there is little, if any, power of 

 accommodation. 



The anatomy of the mammalian eye should be studied 

 in formalin hardened and fresh specimens. The ox eye is 

 the most satisfactory, but that of the sheep or pig may 

 be used. Begin the study of the general relations of the 

 parts using a hardened eyeball cut through the optic axis. 

 Identify: cornea, iris, lens, ciliary body, retina, chorioidea, 

 sclera. If fresh material is not available, study the anterior 

 and posterior segments of the eyeball cut transverse to the 

 optic axis just anterior to the equator. See: Cunningham 

 ('15), pp. 806-827; Gray ('18), pp. 1000-1029; Morris ('14), 

 pp. 1051-1081; Piersol ('16), pp. 1436-1483; Quain ('09), 

 Vol. Ill, Pt. II, pp. 173-264; Rauber-Kopsch ('12), Abteilung 

 VI, pp. 97-170; Sobotta ('11), pp. 247-274; Spalteholz ('09), 

 pp. 770-798; Toldt ('04), pp. 892-910. 



If fresh material is available, determine, if possible, whether 

 you have right or left eye by identifying the eyelids, the 

 rudiment of the nictitating membrane (plica semilunaris), the 

 papillae lacrimales, the naso-lachrimal duct, the ocular 

 muscles, and the point of entrance of the optic nerve. In 

 the ox the compact group of muscles around the optic nerve 

 inserted into the posterior hemisphere of the eyeball is the 

 m. retractor bulbi which is not present in man. 



Remove the conjunctiva and the capsule of Tenon (fascia 

 bulbi) by making a circular incision around the eyeball 

 just behind the sulcus sclerae, carrying it as far as the sclera 

 only and stripping forward and backward to the optic nerve. 

 Look for the trunks of the venae vorticosae emerging from the 

 sclera and the long and short ciliary nerves (Sobotta, '11, 



