Myoneural junctions of extraocular muscles: distances from the orbital rim and widths.
OBJECTIVE
To examine both the distances from the orbital rim to the myoneural junctions (MNJs) and the widths of the MNJs of all extraocular muscles.


METHODS
Six orbits of 3 post-mortem cadavers were used. The cadavers (1 female and 2 males) were all Japanese with an average age of 76.3 years. The MNJs of the extraocular muscles and their motor nerves were exposed, and then the distance from the orbital rim to each MNJ and the width of each MNJ were examined.


RESULTS
The distance from the orbital rim to each MNJ in the 6 extraocular muscles ranged from 24.4 to 33.6 mm and the width of each MNJ ranged from 5.0 to 8.5 mm.


CONCLUSIONS
It is essential for orbital surgeons to understand both the distance from the orbital rim to MNJs and the widths of MNJs. This information not only aids the understanding of MNJ damage, but also prevents iatrogenic nerve impairment during orbital surgery.
Department of Ophthalmology, Aichi Medical University, Aichi-gun, Aichi-ken, 4801-1195, Japan. cosme@d1.dion.ne.jp
Hirohiko
H
Kakizaki
Masahiro
M
Zako
Takashi
T
Nakano
Ken
K
Asamoto
Toshiaki
T
Miyagawa
Masayoshi
M
Iwaki
D000368:Aged; D002102:Cadaver; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009469:Neuromuscular Junction / Q000033:anatomy & histology*; D009801:Oculomotor Muscles / Q000294:innervation*; D009915:Orbit / Q000033:anatomy & histology*