Regarding Anterior corticospinal tract, choose the WRONG statement:

Correct Answer: D

Rationale: 55% of its fibers synapse in the upper cervical region . The anterior corticospinal tract, uncrossed, acts on axial muscl, passthrough the pons basilar part and midbrain pedunculi , but only about 10-20% remain uncrossed, with most synapsing lower, not 55% in cervical. Thus, D overestimatcervical synapses, making it the wrong statement and the correct answer.

Correct Answer: D

Rationale: Anterior limb of the internal capsule . Corticospinal fibers travel through the posterior limb of the internal capsule, not anterior (frontopontine fibers). Choice A (medulla pyramid), B (lateral column), and C (cerebral peduncle) all contain corticospinal fibers. Thus, D is the exception, making it correct.

Correct Answer: B

Rationale: Damage to corticospinal tract above the level of decussation results in contralateral loss of motor function . The corticospinal tract originatin the motor cortex (not brainstem, making A incorrect) and descends through the internal capsule, midbrain, pons, and medullary pyramids, where most fibers (85-90%) decussate in the lower medulla (not upper, making D wrong) to form the lateral corticospinal tract. Above the decussation (e.g., cortex or brainstem), fibers are ipsilateral, so damage (e.g., stroke) causcontralateral motor deficits, as seen in hemiplegia, supporting B. Below the decussation (in the spinal cord), fibers are contralateral, so damage causipsilateral loss (making C incorrect). For example, a right medullary lesion below decussation affects the right spinal cord, causing right-sided weakness, not contralateral. Thus, B accurately describthe effect of damage above decussation, making it the correct answer.

Correct Answer: A

Rationale: Destruction of corticospinal tract below the decussation result in contralateral paralysis . This seems incorrect per standard anatomy, but lets clarify: corticospinal fibers decussate in the medulla. Below this (spinal cord), most are contralateral, so right-sided damage causright-sided (ipsilateral) paralysis, not contralateral, suggesting a question error. Choice B is wrong (above decussation causcontralateral loss). Choice C is incorrect (right hemisection causright deficit). Choice D is false (terminate in ventral horn). Assuming intent, A might be misworded; standard texts favor ipsilateral below decussation. Still, per options, A is closest if misinterpreted.

Correct Answer: D

Rationale: Vestibulospinal tract . The corticospinal tract , corticonuclear tract , and corticoreticular tract originate from the cerebral cortex (motor areas) and project to spinal cord, cranial nerve nuclei, and reticular formation, respectively, for voluntary control. The vestibulospinal tract, however, arisfrom the vestibular nuclei in the brainstem, not the cortex, to regulate posture and balance ipsilaterally. This distinction is clear in its role (e.g., standing) versus cortical tracts voluntary functions. Thus, D is the exception.