title: Extraocular muscle sideslip and orbital geometry in monkeys.
abstract: The belly of each extraocular muscle is elastically coupled to both the globe and orbit. The dependence of muscle planes on gaze angle must be determined experimentally. In monkeys, radio-opaque markers were implanted along the upper and lower margins of a lateral rectus. A scleral search coil was implanted in the other eye. With the eye in various gaze positions, X-ray images were made to show the LR in the lateral view. We found that as the eye rotates vertically over 50 deg (+/- 25 deg), the point of tangency of the LR with the globe slips an average of 5.1 mm vertically with respect to the globe, allowing this point--and so the muscle plane--to remain approximately fixed relative to the orbit. The results of quantitative orbital dissections are presented in support of the sideslip calculations.
authors: Smith-Kettlewell Eye Research Foundation, San Francisco, CA 94115.
authors: J M
authors: JM
authors: Miller
authors: D
authors: D
authors: Robins
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001699:Biometry; D005133:Eye Movements; D008252:Macaca fascicularis; D008255:Macaca radiata; D008297:Male; D009801:Oculomotor Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D009915:Orbit / Q000033:anatomy & histology; D011859:Radiography; D012399:Rotation; D013710:Tendons / Q000033:anatomy & histology