Trochlear nerve

An 8-year-old girl with acute promyelocytic leukemia was given cytarabine, etoposide, idarubicin, and tretinoin 25 mg/m /day (43). Five days later she developed fever, pleural effusions, and ascites, but the symptoms resolved spontaneously. On day 65 (cumulative dose of tretinoin 1.6 g/m ) she had nausea and vomiting, severe headache, and diplopia. There was paralysis of the left trochlear nerve bilateral papilledema. A cranial MRI scan was normal. The intracranial pressure was not measured. Tretinoin was withdrawn and she was given glucocorticoids, mannitol, acetazolamide, and pethidine. Her symptoms resolved within 2 days. 

The extraconal space contains the obhque muscles of the eye, the trochlea, the motoric trochlear nerve, the sensory nerves, some blood vessels, orbital fat tissue, and the lacrimal gland. The lacrimal gland is the largest structure within the extraconal space and Hes behind the orbital rim in the superotemporal quadrant of the orbit. 

COX-1 Constitutive form of cyclooxygenase enzyme. COX-2 Inducible form of cyclooxygenase enzyme, cranial nerve Any of 12 pairs of nerves that arise directly from the brain I (olfactory) II (optic) III (oculomotor) IV (trochlear) V (trigeminal) VI (abducens) VII (facial) VIII (vestibulocochlear) IX (glossopharyngeal) X (vagus) XI (accessory) XII (hypoglossal). They comprise part of the peripheral nervous stem. 

Derouiche, A., Berry, M., and Sievers, J., Regeneration of axons into the trochlear rootlet after anterior medullary lesions in the rat is specific for ipsilateral IVth nerve motomeurones, J. Comp. Neurol., 341, 340, 1994. 

Optic/Oculomotor/Trochlear/Abducent These nerves should be assessed by the following methods ... 

Somatic motor fibers are carried in three cranial nerves to the muscles of the eye, the occulo-motor (III), trochlear (IV), and abducens (VI), and in one to the tongue, hypoglossal (XII). Branchial motor fibers are carried by the trigeminal (V) to the temporalis and masseter muscles, by the facial (VII) to the muscles of expression of the face, by the glossopharyngeal (IX) and vagus (X) to the muscles of the pharynx and larynx, and the accessory nerve (XI) to the sternocleidomastoid and trapezius. 

The trochlear foramen (IV) is positioned high in the orbit, above and slightly behind the optic foramen. Schaeffer (1981, figs. 19 and 25) located the trochlear foramen in a similar position in Tamiobatis vetustus and Cladodus wildungensis, but interpreted it as farther anterior in Orthacanthus (= Xenacanthus ibid, fig. 6) however in another specimen of Orthacanthus the trochlear foramen is located posteriorly (Maisey 1983, fig. 14). Coates and Sequeira (1998) have suggested that the anterior position of the trochlear foramen (relative to the optic nerve) is an apomorphic feature of Hybodus and Tristychius. 

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