The Distribution of the Extraocular Pulley Smooth Muscle in the Rabbit

ABSTRACT

PURPOSE: We evaluated the structure, innervation of the extraocular pulley smooth muscle in the rabbit. METHODS: A rabbit was transcardially perfused with physiological saline followed by 4% formalin. The rabbit orbit was dissected en bloc, paraffin processed, and serially sectioned for Hematoxylin-Eosin and Masson's trichrome stain. The distribution of the extraocular pulley smooth muscle was confirmed by immunohistochemistry with human smooth muscle(SM) alpha-actin. RESULTS: We found that the pulley structure consisted of focal condensations of eleastin and collagenous connective tissue in relationship to the rectus muscle in the equatorial Tenon's fascia. The pulley smooth muscle in relation to medial rectus muscle was immunostained with TH and nNOS. CONCLUSIONS: The data support the presence of the extraocular pulley smooth muscle in the rabbit orbit having both parasympathetic and sympathetic innervation.