**Core Concept**
Proprioception is the sense of the relative position of one's own body parts and strength of effort being employed in movement. It is mediated by proprioceptive receptors, which are mechanoreceptors located in muscles, tendons, and joints.

**Why the Correct Answer is Right**
Proprioception is primarily transmitted by the **dorsal column-medial lemniscus pathway**, which involves the proprioceptive receptors in muscles and joints stimulating the type I (Aβ) afferent fibers in the dorsal root ganglia. These fibers then synapse with the second-order neurons in the dorsal column nuclei of the medulla oblongata. The second-order neurons cross over to the opposite side of the medulla and ascend as the medial lemniscus to the ventral posterior nucleus of the thalamus, where they synapse with the third-order neurons that finally project to the primary somatosensory cortex. This pathway is responsible for transmitting sensations of position, movement, and vibration.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the dorsal column-medial lemniscus pathway is specifically responsible for transmitting sensations of proprioception, not the spinothalamic tract, which is responsible for transmitting sensations of pain and temperature.
**Option B:** This option is incorrect because the corticospinal tract is a motor pathway that transmits signals from the cerebral cortex to the spinal cord, not a sensory pathway that transmits proprioceptive information.
**Option C:** This option is incorrect because the trigeminal nerve primarily transmits sensory information from the face, not proprioceptive information from the body.

**Clinical Pearl / High-Yield Fact**
The dorsal column-medial lemniscus pathway is often affected in conditions such as tabes dorsalis, a complication of syphilis that causes degeneration of the dorsal columns in the spinal cord, leading to loss of proprioception and vibration sense.

**Correct Answer:** D. Dorsal column-medial lemniscus pathway