The corticospinal tract crosses the midline at the level of the
A) superior colliculi of the midbrain.
B) junction between the midbrain and pons.
C) junction between the pons and medulla.
D) junction between the medulla and spinal cord.

Question

Quizplus · Accepted Answer

The corticospinal tract, also known as the pyramidal tract, crosses the midline at the junction between the medulla and spinal cord. At this level, the fibers of the tract decussate to form the lateral corticospinal tract which innervates the limbs and the ventral corticospinal tract which innervates the axial muscles. Option A is incorrect because the superior colliculi of the midbrain are involved in visual and auditory processing. Option B is incorrect because the junction between the midbrain and pons is the site of the corticobulbar tract, not the corticospinal tract. Option C is incorrect because the junction between the pons and medulla is the site of the trigeminal motor nucleus and the origin of the trigeminal nerve.

The Corticospinal Tract Crosses the Midline at the Level of the