Demonstration of the nerve distribution of the extraocularmuscles in rabbits (Oryctolagus cuniculus)

Abstract

Purpose. The intramuscular nerve distribution of the extraocular muscles may be of utmost importance for better understanding of their physiologic and pathologic reactions. The aim of this study was to determine the entire intramuscular nerve distribution pattern of rabbit extraocular muscles by utilizing Sihler's staining technique. Methods. Six New Zealand rabbits were used in order to demonstrate the intramuscular nerve distribution of the extraocular muscles by using Sihler's staining method. Results. The number of extramuscular and intramuscular major nerve branches were higher in the inferior oblique muscle while the number of intramuscular minor nerve branches were higher in the superior oblique muscle when compared with the other extraocular muscles. The smallest number of extramuscular branch and intramuscular both major and minor branches were found in the medial rectus muscle. More complex anastomoses and a branching pattern were observed in the superior oblique and superior rectus muscle. The anastomosing nerve branches were observed to run in a "Y", "I" or "U"-shaped pattern in all of the extra-ocular muscles. Of all the extraocular muscles, the longest major nerve branches were observed in the retractor bulbi muscles. However, these branches had the smallest diameter. No morphological difference was observed between the two sides with regard to all the characteristics of the extraocular muscles. Conclusion. Sihler's neural staining technique could be quite useful in the demonstration of the intramuscular nerve distribution of extraocular muscles.