Which of the following anchors spinal cord to coccyx:

Correct Answer: B

Rationale: Filum terminale . The filum terminale is a slender, thread-like extension of the pia mater that descends from the conus medullaris (the tapered end of the spinal cord) and anchors the spinal cord to the coccyx, providing longitudinal stability. Choice A, Denticulate ligament, is incorrect because these are lateral extensions of the pia mater that anchor the spinal cord to the dura mater along its sides, not to the coccyx. Choice C, Cauda equina, refers to the bundle of spinal nerve roots below the conus medullaris and donot anchor the spinal cord. Choice D, Conus medullaris, is the terminal end of the spinal cord itself, not an anchoring structure. Thus, Filum terminale is the specific structure that tethers the spinal cord to the coccyx, confirming B as the correct answer.

Correct Answer: C

Rationale: Denticulate ligaments are lateral extensions of the arachnoid mater , which is false. Denticulate ligaments are extensions of the pia mater, not arachnoid, anchoring the spinal cord to the dura. Choice A is true (sympathetic neurons are in the lateral horn, T1-L2). Choice B is correct (spinal cord ends at L1-L2 in adults). Choice D is accurate (31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal). Thus, C misattributthe denticulate ligaments to the arachnoid instead of the pia, making it the false statement and the correct answer.

Correct Answer: D

Rationale: Posterolateral direction . Disc herniation most commonly occurs posterolaterally because the posterior longitudinal ligament, which reinforcthe disc posteriorly, is narrower and weaker laterally, allowing the nucleus pulposus to protrude toward the sidof the spinal canal, often compressing nerve roots. Choice A, Posteromedial, is less common due to the ligaments central strength. Choice B, Anteromedial, is rare as the anterior longitudinal ligament prevents anterior herniation. Choice C, Superior, is incorrect as herniations dont typically project upward. Thus, Posterolateral is the most frequent direction, making D the correct answer.

Correct Answer: C

Rationale: Synapse in ventral posteromedial nucleus of the thalamus . The lateral spinothalamic tract, carrying pain and temperature, synapsin the ventral posterolateral (VPL) nucleus of the thalamus, not the ventral posteromedial (VPM) nucleus, which processfacial sensations via the trigeminal pathway. Choice A is correct (crossvia anterior white commissure). Choice B is true (projects widely to cortex). Choice D is accurate (pain and temperature). Thus, C misidentifithe thalamic nucleus, making it the wrong statement and the correct answer.

Correct Answer: D

Rationale: The dorsal column medial lemniscal pathway . This pathway carriconscious proprioception (position sense), vibration, and fine touch. Damage prevents the patient from sensing toe position with eyclosed. Choice A (spinothalamic) carripain and temperature, not proprioception. Choice B (precentral gyrus) is motor, not sensory. Choice C (ventral spinal cord) affects motor tracts, not proprioception. Thus, D identifithe correct pathway for position sense, making it the right answer.