False about the trochlear nerve: (AIIMS Nov 2013)
|A||is vulnerable to head injury|
|B||crosses within the anterior medullary vellum|
|C||lies in the lateral wall of the cavernous sinus|
|D||innervates the superior oblique muscle on its inferior surface|
1. The trochlear nerve provides innervation to the superior oblique muscle only. Its nucleus is located in the midbrain, at the level of inferior collocule
2. The axons exit dorsally and cross within the anterior medullary velum.
3. Thus, innervation to the superior oblique muscles is strictly contralateral.
4. Although the trochlear nerve passes through the superior orbital fissure, it enters the orbit outside the annulus of Zinn and crosses above the superior rectus muscle en route to innervate the superior oblique muscle.
5. The trochlear nerve innervates the superior oblique muscle on its superior surface.