Loss of feel of size & shape of a object is seen in lesion ofa) Tractus solitariusb) Tractus cuneatusc) Lateral spinothalamic tract d) Cerebral cortex

**Question:** Loss of feel of size & shape of a object is seen in lesion of:

A) Tractus solitarius
B) Tractus cuneatus
C) Lateral spinothalamic tract
D) Cerebral cortex

**Core Concept:** The correct answer relates to the sensory pathways involved in proprioception, which is the sense of body position and movement. These pathways transmit information about the position and movement of body parts to the brain, allowing us to perceive our body's spatial relationship with the environment.

**Why the Correct Answer is Right:** The correct answer, D) Cerebral cortex, refers to the primary somatosensory cortex, which is responsible for processing sensory information from the body. Damage to this area can lead to a loss of proprioception, causing the described symptoms of impaired perception of object size and shape.

**Why Each Wrong Option is Incorrect:**

A) Tractus solitarius: This is a part of the vagal nucleus, involved in processing information about pain, temperature, and pressure sensation. It is not responsible for proprioception, making this option incorrect.

B) Tractus cuneatus and tractus gracilis: These tracts are part of the ventral posterior nucleus of the thalamus and process information about light touch and pressure sensation, not proprioception.

C) Lateral spinothalamic tract: This tract is responsible for processing thermal and mechanical information, not proprioception.

**Loss of feel of size & shape of an object** can be explained as follows:

- Proprioception arises from the integration of sensory inputs from various sensory modalities, including the lateral spinothalamic tract, tractus cuneatus, and tractus gracilis. Damage to these pathways can lead to a loss of the sense of position and movement of body parts, causing the described symptoms of impaired perception of object size and shape.

**Clinical Pearl:** The correct answer, D) Cerebral cortex, highlights the importance of the primary somatosensory cortex in processing sensory information from the body, particularly proprioception. Proprioception is essential for maintaining balance, coordination, and overall body awareness, making any damage to the areas responsible for processing sensory information from the body a potential cause for the described symptoms.