Medical ophthalmology / by Arnold Knapp.

  • Knapp, Arnold Herman, 1869-1956.
Date:
[1918]
Catalogue details

Licence: Public Domain Mark

Credit: Medical ophthalmology / by Arnold Knapp. Source: Wellcome Collection.

    51/536 (page 31)
    anterior part of the mesial nucleus serves principally the pupil, which means primarily the light reaction of the pupil. Opinions differ on the importance of the Edinger-Westphal nucleus; we know only that it belongs to the oculomotor nerve. The root fibres pass outward from this oculomotor nu- cleus, crossed and partly uncrossed. All fibres of the mesial nucleus are uncrossed. The fibres of the lateral nucleus are crossed and, in fact, partially crossed, especially the fibres from the lateral nucleus to the internal rectus are crossed. It has already been mentioned that the trochlear fibres decussate. ‘The decussation takes place in the velum medullare anterius. The fibres of the abducent nerve leave the nucleus on its mesial side. They do not pass directly out to the ventral surface, but are directed some- what caudally in order to reach the base of the pons near the middle line. While the two last-mentioned nerves form enclosed bundles, the oculomotor nerve splits up into a number of small bundles which are separated and do not join together until just before their exit at the peduncle or just beyond this point sometimes at a distance of 14 cm. The ocular muscle nuclei have important relation to the principal conducting paths and to the nuclei of the mid- brain and of the medulla oblongata. The fasciculus longi- tudinalis posterior is closely related to the oculomotor nucleus and is indented by the trochlear nucleus, while the abducent nucleus is situated on its lateral surface. In the mid-brain the nucleus ruber comes into relation on its ven- tral surface with the oculomotor fibres which pass through it. Furthermore should be mentioned the tracts of the tegmentum (sensory paths) and those of the pes peduncul1, 1.e., the motor paths in this as well as in the pons. The SyNDROMES which are produced by a combined lesion of the ocular muscles and of the above-mentioned nuclei and tracts are the following: 1. Mid-brain. (a) Weber’s syndrome. Site of lesion: Pes pedunculi.