Anatomy books

Wednesday, March 14, 2018

Dilator pupillae


Dilator pupillae

They are involuntary  muscle fibers of the iris , which running radially from papillary margin to periphery .
It is supplied by sympathetic nerves from the superior cervical ganglion. It is widening the pupil and allowing for more light to pass through the eye.

Some condition like carcinoma of the lung, thyroid or oesophagus or metastatic lymph nodes may involve sympathetic trunk and give rise Horner’s syndrome,. One of the  characteristic feature of Horner’s syndrome is  slight constriction of pupil because dilator papillae muscle  losses it innervations  so fail to dilate pupil .  

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