A patient met with a road traffic accident and developed a cervical spine injury. The fracture fragment had pierced the lateral aspect of the dorsal column tract. Which of the following findings is seen in this patient?

Correct Answer: B. Absence of ipsilateral arm proprioception

The dorsal column tract (fasciculus gracilis and cuneatus) carries ipsilateral proprioception and fine touch from the body to the medulla. A lateral lesion of the dorsal column at the cervical level specifically damages the fasciculus cuneatus, which transmits proprioceptive and discriminative touch information from the ipsilateral upper limb and arm. This tract ascends ipsilaterally without crossing until it reaches the medulla, where it synapses in the nucleus cuneatus and then crosses as internal arcuate fibers to form the medial lemniscus. Therefore, a lateral cervical dorsal column injury results in loss of ipsilateral arm proprioception — the patient cannot sense the position of their arm in space. This is a classic Brown-Séquard syndrome variant when combined with contralateral spinothalamic tract involvement. The key discriminator is that the dorsal column lesion is ipsilateral and above the medulla (before crossing), making proprioception loss ipsilateral to the injury side.

Why the other options are wrong

A. Absence of fine motor movement of fingers — Fine motor movement depends on the corticospinal tract (pyramidal tract), not the dorsal columns. A lateral dorsal column injury does not directly damage the corticospinal tract, which lies in the lateral funiculus. Motor deficits would occur with anterior horn cell or corticospinal involvement, not dorsal column injury. This option confuses sensory (dorsal column) with motor (corticospinal) pathways — a common NBE trap. C. Absence of ipsilateral lower limb proprioception — The fasciculus gracilis (not cuneatus) carries proprioception from the lower limb. At the cervical level, a lateral lesion damages the fasciculus cuneatus (lateral dorsal column), which is concerned with upper limb proprioception. The fasciculus gracilis lies medially and would be spared in a purely lateral cervical lesion. This option represents confusion about the somatotopic organization of the dorsal columns. D. Absence of contralateral lower limb proprioception — Proprioception loss from dorsal column injury is always ipsilateral because the dorsal columns ascend without crossing until the medulla. Contralateral loss would occur with spinothalamic tract (pain/temperature) lesions, which cross at the spinal cord level. This option incorrectly applies the crossing pattern of the spinothalamic tract to the dorsal columns — a critical anatomical error.

High-Yield Facts

Mnemonics

DCCC Rule Dorsal Columns = Cranial crossing (at medulla, not spinal cord) = Contralateral loss is NOT seen. Dorsal column loss is always ipsilateral. Cuneatus = Upper, Gracilis = Lower Cuneatus (lateral, upper limb) vs Gracilis (medial, lower limb). At cervical level, lateral lesion → cuneatus damage → upper limb proprioception loss. Brown-Séquard = Ipsi-Dorsal + Contra-Spino Lateral cord lesion gives ipsilateral dorsal column loss (proprioception) + contralateral spinothalamic loss (pain/temperature). Remember: dorsal = ipsilateral, spino = contralateral.

NBE Trap

NBE pairs dorsal column injury with motor deficits (option A) to trap students who confuse sensory pathways with motor pathways. Additionally, options C and D exploit confusion about whether dorsal column loss is ipsilateral or contralateral — students who incorrectly apply spinothalamic crossing rules to dorsal columns will select the wrong answer.

Clinical Pearl

In Indian trauma centres, cervical spine injuries from road traffic accidents are common. A patient with lateral cervical cord injury (Brown-Séquard pattern) will present with inability to sense arm position (ipsilateral proprioception loss) while retaining pain sensation, or vice versa — this dissociated sensory loss is the clinical hallmark that helps localize the lesion to the spinal cord rather than brain.

_Reference: Guyton & Hall Textbook of Medical Physiology, Ch. 48 (Sensory Pathways); Robbins & Cotran Pathologic Basis of Disease, Ch. 28 (Nervous System)_