Trochlear and abducens nerve (Latin)

The n. trochlearis (CN IV) arises from the ncl. nervi trochlearis, (containing general somatic efferent (GSE) neurons) which is located in the tegmentum of the caudal midbrain. Fibers from this nucleus decussate posteriorly and emerge from the dorsal midbrain, just below the colliculus inferior. From here, the n. trochlearis curves around the midbrain, passing through the lateral wall of the sinus cavernosus, superior and lateral to the n. oculomotorius. It continues into the orbit via the fissura orbital superior, external to the anulus tendineus communis, before terminating in the m. obliquus superior.The n. abducens (CN VI) arises from the ncl. nervi abducentis, which also contains general somatic efferent (GSE) neurons and is located near the fossa rhomboidea/floor of the ventriculus quartus. Fibers from this nucleus exit the brainstem at the sulcus bulbopontinus (junctio pontomedullaris) as the n. abducens, which courses through the sinus cavernosus (along the a. carotis interna). It then enters the orbit via the fissura orbitalis superior, internal to the anulus tendineus communis. The n. abducens nerve penetrates the medial surface of the m. rectus lateralis which functions as an abductor of the eyeball.