Which of the following is not carried in dorsal column of spinal cord:March 2011
**Core Concept**
The dorsal column of the spinal cord is responsible for transmitting sensory information related to proprioception, vibration, and fine touch from the body to the brain. This information is carried through the posterior (dorsal) roots of the spinal nerves and is relayed to the gracile and cuneate nuclei in the medulla oblongata.
**Why the Correct Answer is Right**
Heat sensation is mediated by the spinothalamic tract, which is a separate pathway that carries information related to pain, temperature, and crude touch. The spinothalamic tract is located in the anterolateral (anterior and lateral) part of the spinal cord, not in the dorsal column. This pathway is essential for the transmission of painful and thermal sensations from the body to the brain. The spinothalamic tract is crossed at the level of the spinal cord, meaning that the left side of the body is represented on the right side of the brain and vice versa.
**Why Each Wrong Option is Incorrect**
**Option A:** Proprioception is indeed carried in the dorsal column, specifically through the posterior (dorsal) roots of the spinal nerves. This information is necessary for the brain to understand the position and movement of the body.
**Option B:** Vibratory sense is also transmitted in the dorsal column, through the posterior (dorsal) roots of the spinal nerves. This information is essential for the brain to understand the sensation of vibration and fine touch.
**Option D:** Touch is carried in the dorsal column, through the posterior (dorsal) roots of the spinal nerves. This information is necessary for the brain to understand the sensation of light touch and pressure.
**Clinical Pearl / High-Yield Fact**
The dorsal column pathway is often referred to as the "posterior column-medial lemniscus pathway." This pathway is responsible for transmitting information related to proprioception, vibration, and fine touch from the body to the brain. Damage to this pathway can result in loss of proprioception and fine touch sensation, which is often seen in conditions such as tabes dorsalis.
**✓ Correct Answer: C. Heat sensation**