Choose the incorrect pair of (tract - level of decussation):

Correct Answer: D

Rationale: Pontine reticulospinal tract - spinal cord , which is incorrect. The pontine reticulospinal tract descends ipsilaterally, with no decussation. Choice A (corticospinal - medulla), B (spinothalamic - spinal cord), and C (rubrospinal - brainstem/midbrain) are correct. Thus, D misattributdecussation, making it the incorrect pair and the correct answer.

Correct Answer: D

Rationale: control voluntary movement. The corticospinal tract originatfrom the primary motor cortex (precentral gyrus, not just premotor, making B incomplete), decussatin the medullary pyramids (not midbrain, making A wrong), and terminatin the ventral horn (not posterior, making C incorrect). Its primary function is to control voluntary movements, particularly fine motor skills (e.g., hand movements), via upper motor neurons synapsing on lower motor neurons. Damage, like in stroke, impairs voluntary actions contralaterally. Thus, D accurately reflects the corticospinal tracts role, making it the correct answer.

Correct Answer: D

Rationale: Fibers of corticospinal tract pass through the anterior limb of the internal capsule . Corticospinal fibers pass through the posterior limb of the internal capsule, not anterior (frontopontine fibers). Choice A is correct (passthrough medullary pyramids). Choice B is true (below decussation, damage causipsilateral paralysis). Choice C is accurate (synapson alpha motor neurons). Thus, D mislocatthe fibers, making it the wrong statement.

Correct Answer: D

Rationale: control voluntary movement . The corticospinal tract originatfrom the motor cortex (not cerebellum, making B wrong), decussatin the medullary pyramids (not pons, making A incorrect), and terminatin the ventral horn (not posterior, making C false). It controls voluntary movements, like fine motor skills, via upper motor neurons to spinal motor neurons. This role is critical, as seen in paralysis post-lesion. Thus, D is the true statement.

Correct Answer: C

Rationale: Control voluntary movement of the muscle of the face only , which is false. The corticonuclear tract originatfrom the precentral gyrus (A is true), descends through the internal capsule, and terminatin brainstem cranial nerve nuclei (B is true), such as 5 (jaw), 7 (face), 10 (pharynx), and 12 (tongue). It controls voluntary movements not just of the face, but also head and neck muscl(e.g., tongue, larynx), making C inaccurate. Fibers decussate partially in the brainstem (D is true), with variations e.g., lower facial fibers cross, but upper facial innervation is bilateral. This broader role is evident in deficits like contralateral tongue deviation or dysphagia from lesions, not face-only effects. Thus, C is the exception, as it wrongly limits the tracts function, making it the correct answer.