Robert S Jampel1, Dian X Shi. 1. Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, Michigan, 48201, USA.
Abstract
PURPOSE: To provide evidence against the existence of orbital pulleys. METHODS: Interpretation of magnetic resonance imaging (MRI) scans; video eye tracking; ocular motor nerve stimulations; and clinical observations. RESULTS: No pulleys or planes splitting the extraocular muscles into layers were noted on MRI scans. Smooth muscle does not antagonize striate muscle. There is no physiological evidence that human rectus pulleys shift the ocular rotational axes to attain commutative behavior. In the monkey and humans, the axes of rotation are not determined by eye position. Operations on the extraocular muscles reveal no pulleys. CONCLUSIONS: The somatosensory system of the central nervous system controls the extraocular muscles. The autonomic nervous and the hormonal systems control the infrastructure of the orbit vital for the function of the extraocular muscles. The three systems are integrated and controlled by the central nervous system. Neural circuits are necessary to compensate for extraocular muscle abnormalities. There are no pulleys.
PURPOSE: To provide evidence against the existence of orbital pulleys. METHODS: Interpretation of magnetic resonance imaging (MRI) scans; video eye tracking; ocular motor nerve stimulations; and clinical observations. RESULTS: No pulleys or planes splitting the extraocular muscles into layers were noted on MRI scans. Smooth muscle does not antagonize striate muscle. There is no physiological evidence that human rectus pulleys shift the ocular rotational axes to attain commutative behavior. In the monkey and humans, the axes of rotation are not determined by eye position. Operations on the extraocular muscles reveal no pulleys. CONCLUSIONS: The somatosensory system of the central nervous system controls the extraocular muscles. The autonomic nervous and the hormonal systems control the infrastructure of the orbit vital for the function of the extraocular muscles. The three systems are integrated and controlled by the central nervous system. Neural circuits are necessary to compensate for extraocular muscle abnormalities. There are no pulleys.