Brain MRI was requested for this 45 YO patient with diplopia to rule out multiple sclerosis. Axial & coronal images show focal dehisce...
Brain MRI was requested for this 45 YO patient with diplopia to rule out multiple sclerosis. Axial & coronal images show focal dehiscence of the left lamina paprycea with focal herniation of orbital fat into ethmoid sinus (arrows). The medial rectus muscle has slight irregular contour. No previous history of trauma or surgery.
Dehiscence of the lamina paprycea may be congenital or acquired (after trauma or surgery). The characteristic feature of dehiscence is a bony defect in the medial orbital wall or an inward displacement of the wall into the ethmoidal complex.
The orbital fat and the medial rectus muscle often protrude through this gap into the ethmoidal bulla, which is usually small in size. Other orbital structures like optic nerve or even the globe itself
may herniate.
Clinical relevance: this abnormality when recognized should be reported to otolaryngologists to avoid possible complications e.g. perforation of the orbital wall and damage to the globe & extra-ocular muscles during FESS (Functional Endoscopic Sinus Surgery).
