Discriminatory touch from the upper extremities is carried by which fasciculus?

Discriminatory touch from the upper extremities is carried by which fasciculus?

• A. Fasciculus Cuneatus
• B. Fasciculus Gracilis
• C. Spinothalamic Tract
• D. Corticospinal Tract

Answer: (A)

Fine discriminatory touch from the upper extremities travels via the fasciculus cuneatus, part of the dorsal column–medial lemniscus pathway. This tract carries tactile discrimination and proprioceptive information from the arms and upper trunk, ascending in the dorsal columns to the nucleus cuneatus in the medulla. From there, second-order neurons cross and form the medial lemniscus to the ventral posterior lateral nucleus of the thalamus and then to the somatosensory cortex. The fasciculus gracilis handles similar information from the lower body, the spinothalamic tract carries crude touch and pain/temperature, and the corticospinal tract is motor. Therefore, the fasciculus cuneatus is the correct carrier for discriminatory touch from the upper extremities.

Fine discriminatory touch from the upper extremities travels via the fasciculus cuneatus, part of the dorsal column–medial lemniscus pathway. This tract carries tactile discrimination and proprioceptive information from the arms and upper trunk, ascending in the dorsal columns to the nucleus cuneatus in the medulla. From there, second-order neurons cross and form the medial lemniscus to the ventral posterior lateral nucleus of the thalamus and then to the somatosensory cortex. The fasciculus gracilis handles similar information from the lower body, the spinothalamic tract carries crude touch and pain/temperature, and the corticospinal tract is motor. Therefore, the fasciculus cuneatus is the correct carrier for discriminatory touch from the upper extremities.