Electromyographic Evidence for Ocular Muscle Proprioception in Man

The question of extraocular muscle proprioception * has been labored long and vehemently in ophthalmologic literature. The existence of muscle sense, that is, a knowledge of the position of the eyes due to messages from the ocular muscles, strongly advocated by Sherrington,1has now been generally denied. The information derived from vision and the innervational urge are said to be adequate to explain our awareness or lack of awareness of eye position.2,3That the extraocular muscles should lack a mechanism for the recording of muscle tension, however, would place them so far apart from other skeletal muscle as to arouse wonder and doubt that they should be so distinguished. The fact that the extraocular muscles do have anatomic and pharmacologic peculiarities has been long appreciated. The existence of unusual nerve endings in these muscles has been reported, and the occurrence of muscle spindles and other low-threshold stretch receptors has