• Drooping of the upper eyelid associated with the inability to elevate the eyelid completely

1. Innervation
   • Levator palpebrae superioris - dual origin and innervation
   • Skeletal muscle: III cranial nerve (oculomotor)
   • Smooth muscle (Muller's muscle): postganglionic sympathetic nerve fibres from superior cervical ganglion
2. Types of ptosis
   • Complete: III n palsy - eyelid droops in all positions
   • Partial: ipsilateral sympathetic lesion (seen in horner's syndrome [ptosis, meisosi, anhydrosis and enophthalmos])

Approach

• Best observed with patient sittingup and head being held by the examiner

Inspect

1. Unilateral or bilateral
2. Partial or complete (ask patient to look upwards - uses IIIn)
3. Look at size of pupil
   • Small in Horner's syndrome
   • Large pupil: IIIn palsy, and test reaction to light and accommodation [pupil does not react in IIIn palsy]

Completion

1. History
2. Find out cause of ptosis
   • Horner's syndrome - secondary to
     1. Pancoast tumour of lung: apical lung carcinoma that invades the cervical sympathetic plexus, associated with shoulder and arm pain due to brachial plexus invasion of C8-T2 and hoarse voice or bovine cough due to unilateral recurrent laryngeal nerve palsy and vocal cord paralysis_
     2. Lower brachial plexus injury: Dejernine-Klumpke paralysis
   • IIIn palsy - complete ptosis
   • Syphillis
   • Congenital ptosis
   • Myopathies: myasthenia gravis, dystrophia myotonica

Treatment: 

• blepharoplasty