Given her atypical presentation, we got MRI of orbit with contrast done that revealed ill-defined mixed signal intensity lesion in the intraconal compartment of the left orbit involving Medial Rectus, Inferior Rectus and posterior part of the
Superior Rectus muscles.
A conjunctival incision was made in the superotemporal quadrant 8 mm from the limbus, the
superior rectus (SR) muscle was isolated and the SO muscle was exposed from the lateral side.
b) Overaction of inferior rectus and underaction of
superior rectus on left eye chart
The inferior portion of the mass also eroded the roof of the left orbit, with extension into the extraconal orbital compartment and compression of the
superior rectus muscle (figure 3).
The levator palpebrae superioris, pupillary sphincter muscle, and four extraocular muscles (the
superior rectus, inferior rectus, medial rectus, and inferior oblique muscles) are innervated by the oculomotor nerve.
MRI images of the disease reportedly show unilateral enlargement of the extraocular muscle (especially
superior rectus or lateral rectus muscles) that involves the tendons with vague contour of the muscle [3, 13].
Besides, it is said that the subnuclei of the
superior rectus muscle control the contralateral side [11].
A study evaluating the reattachment site of the
superior rectus muscle after hang-back recession in rabbits showed that, the higher the amount of recession, the bigger the risk and amount of muscle advancement [15].
We also found out that patient selection is very important and therefore, a detailed preoperative assessment of ptosis especially to rule out associated
superior rectus weakness, poor Bells phenomenon and other associated systemic and ocular disorders must be carried out in every patient.
Muscle width and thickness were measured for individual muscles (inferior rectus, medial rectus, lateral rectus,
superior rectus and superior obliquus).
They innervate
superior rectus, inferior rectus, medial rectus and inferior oblique muscle, and levator palpebrae muscle.
Year Author Age Extraocular Histopathologic muscle involved type of IMH 2002 Christensen 21 yrs MR, LR, IR, SO Mixed 2003 Kiratli 3 yrs LR Capillary 2003 Kiratli 40 yrs MR Mixed 2006 Kim 63 yrs SR Cavernous 2009 Lee 31 yrs MR Cavernous 2014 Charles 25 yrs IO Capillary MR: medial rectus; LR: lateral rectus; IR: inferior rectus; SR:
superior rectus; IO: inferior oblique; SO: superior oblique.