For instance, a patient with mild
inferior rectus muscle weakness might have a hypertropia on down gaze, but none in the primary position of gaze, whereas in complete CN III palsy, the patient may experience complete ptosis, the eye involved is deviated downward, outward and it is unable to adduct, infraduct, or even supraduct.
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.
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.
Additionally, the orbital floor fracture occurred just immediately behind the equator of the globe, that is, at the main bulk of the
inferior rectus muscle.
CT scan showed obvious enlargement of the
inferior rectus muscle of the left eye (Figure 1(c)).
riMLF: rostral interstitial nucleus of medial longitudinal fasciculus, iNC: interstitial nucleus of Cajal, CCN: caudal central subnucleus, MLF: medial longitudinal fasciculus, III N: oculomotor nucleus, VI N: abducens nucleus, IO: intraocular muscles, SR: superior rectus muscle, MR: medial rectus muscle, Lid: Levator palpebrae superioris muscle, IR:
inferior rectus muscle, and pupil: sphincter pupillae muscles.
Most involve injury to the medial rectus muscle via violation of the lamina papyracea, while the orbital floor and adjacent
inferior rectus muscle is generally not considered a high-risk area [6].
Intraoperative findings showed a cystic mass on the surface of the right
inferior rectus, with intact cystic wall enclosing caviar-like particles and transparent cystic fluid.
(5) reported a case with recurrent ocular involvement which was consistent with central retinal vein occlusion/venous stasis retinopathy in the first attack, and
inferior rectus paralysis in the second attack and was treated with steroids.
For these intraorbital GCT cases, extraocular muscle involvement (79.3%) and diplopia (84.6%) are the most common features.[sup][1] The tumor mostly located in the lower half of the orbit (58.3%) and the
inferior rectus was the most commonly involved muscle (38.5%).[sup][1]
The horizontal diameters of the medial and lateral rectus and the vertical diameters of the superior and
inferior rectus were measured on the series of images; the largest diameter of the middle section of each muscle was selected for further comparison.
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.