The upper eyelid is raised by the action of the levator palpebrae superioris and Müller's palpebral muscle. The former is innervated by the oculomotor nerve and the latter by fibers from the cervical portion of the sympathetic trunk. Ptosis of the upper lid follows paralysis of either nerve supply, that due to a lesion of the oculomotor nerve being greater than the slight droop which is seen in Horner's syndrome1 due to involvement of the cervical portion of the sympathetic trunk (figure, A). Likewise, there is limitation of the upward excursion of the lid when the eyeball is elevated in disorders referable to the oculomotor nerve while in disturbances of the sympathetic innervation the amplitude is normal. With section of the third nerve mydriasis occurs as well as external and internal ophthalmoplegia, while a lesion of the sympathetic trunk causes miosis and enophthalmos.
This communication deals with ptosis produced
MAHONEY W, SHEEHAN D. EXPERIMENTAL PTOSIS IN PRIMATES. Arch NeurPsych. 1936;35(1):99–108. doi:10.1001/archneurpsyc.1936.02260010109008
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