Intraorbital

Intraorbital refers to anything located within the orbit, the bony cavity that houses the eyeball and its surrounding structures. The term is used in anatomy, radiology, and clinical medicine to distinguish within the orbital space from intraocular (within the globe) or intracranial (within the skull).

The orbit contains the globe, extraocular muscles, the optic nerve and its sheath, the ophthalmic artery and veins, cranial nerves II through VI, fat, lacrimal apparatus, and surrounding connective tissue. The intraconal space lies inside the muscle cone that surrounds the optic nerve, while the extraconal space lies outside this cone. The arrangement of these structures has important clinical implications for signs such as diplopia, proptosis, and vision loss.

Intraorbital pathology encompasses trauma, infection, inflammatory disease, and neoplasia. Common problems include orbital fractures with potential entrapment of extraocular muscles, retrobulbar or orbital hemorrhage, orbital cellulitis, and inflammatory conditions like orbital myositis. Neoplasms may arise in the orbit, such as optic nerve glioma or meningioma, and vascular lesions can occur within the intraorbital space. Symptoms typically include double vision, eye swelling, pain, protrusion of the eye, and reduced visual acuity or afferent pupil abnormalities.

Diagnosis relies on imaging and clinical examination. Computed tomography is usually the first-line modality for acute trauma and bony assessment, while magnetic resonance imaging provides superior soft tissue detail for nerves, muscles, and tumors. Management is pathology-dependent and may range from observation and antibiotics to surgical intervention for fractures or decompression in cases of compressive optic neuropathy.