**Question:** In adults, spinal cord ends at the lower end of:

A. T12
B. L1
C. L2
D. L3

**Core Concept:**
The spinal cord is a part of the central nervous system, responsible for transmitting sensory and motor information between the brain and the rest of the body. In adults, it extends from the brainstem (cerebellum and medulla) to the conus medullaris, which is located at the lower end of the spinal cord.

**Why the Correct Answer is Right:**
The correct answer is D. L3 because:

1. The spinal cord ends at the conus medullaris, which is located in the caudal part of the lumbar spinal cord. The conus medullaris is usually found at the level of L3-L4 vertebrae in adults.
2. In children, the conus medullaris is higher, usually at the level of S2-L2 vertebrae due to the elongated spinal cord.
3. A misconception to avoid is considering the spinal cord as a single structure without understanding the anatomical variations in its length and location.

**Why Each Wrong Option is Incorrect:**
A) T12: The spinal cord extends higher than this level, as it ends at the conus medullaris (D).
B) L1: The spinal cord ends at a lower level than this vertebra (D).
C) L2: Similar to option D, the spinal cord ends at a lower level than this vertebra (D).

**Clinical Pearl:**
Understanding the location of the conus medullaris is essential in diagnosing various clinical scenarios, such as:

- Trauma: Can lead to spinal cord injury and neurological deficits below the injury level.
- Neurological assessment: Assessing the level of injury or deficit can provide valuable information about the extent of the spinal cord damage.
- Diagnosis: Accurate identification of the spinal cord level can guide the diagnosis of various spinal cord disorders and guide treatment decisions.

Remember, in adults, the spinal cord ends at the conus medullaris, which is typically located at the level of L3-L4 vertebrae.