Which of the following statements concerning the white columns of the spinal cord is correct:

Correct Answer: B

Rationale: The anterior spinothalamic tract is found in the anterior white column . The anterior spinothalamic tract, carrying crude touch, ascends in the anterior (ventral) white column of the spinal cord after crossing. Choice A is wrong (posterior spinocerebellar is in the lateral column). Choice C is incorrect (lateral spinothalamic is in the lateral column). Choice D is false (fasciculus gracilis is in the posterior column). Thus, B correctly locatthe anterior spinothalamic tract, making it the right answer.

Correct Answer: D

Rationale: Their function is subconscious regulation of balance and muscle tone . The lateral corticospinal tract, a pyramidal tract , controls voluntary fine movements, not subconscious balance/tone (extrapyramidal role). Choice B and C are correct (passthrough midbrain pedunculi and pons basilar part). Thus, D misattributfunction, making it the wrong statement and the correct answer.

Correct Answer: A

Rationale: Located in the anterior white column . The rubrospinal tract, from the red nucleus , cross, facilitatflexors , and runs in the lateral white column, not anterior (ventral corticospinal is anterior). Thus, A misplace the tract, making it the wrong statement and the correct answer.

Correct Answer: B

Rationale: Rubrospinal tract mainly supply the distal extensors musclwith little effect on the proximal muscl. The rubrospinal tract facilitatflexors, not extensors, especially distally. Choice A, C, D are correct (vestibulospinal for antigravity, tectospinal for reflexes, medullary in lateral column). Thus, B misattributflexor/extensor roles, making it the wrong statement and the correct answer.

Correct Answer: D

Rationale: The anterior commissure connect the two halvof the mesencephalon , which is false. The anterior commissure connects the temporal lob(telencephalon), not the mesencephalon (midbrain). Choice A, B, C are true (pyramidal from precentral, sensory to thalamus, association fibers). Thus, D is the false statement, making it correct.