A trauma patient is diagnosed with a complete T4 spinal cord injury. Which finding is most likely?

NORCET 9 Prelims-2025

Medical & Surgical Nursing

Medium

Appeared in: NORCET 9 Prelims-2025

Explanation

A complete spinal cord injury at the T4 level interrupts all motor and sensory signals below the injury site.
The T4 dermatome is located at the level of the nipple line.
This results in paraplegia: paralysis and sensory loss affecting the trunk and both lower extremities.
Function of the arms, hands, and diaphragm remains intact because their nerve supply originates from spinal levels above T4.

Option A: Profound upper extremity weakness (tetraplegia) is seen with injuries to the cervical spine (C1-C8), which is located above the T4 level.
Option B: The diaphragm is innervated by the phrenic nerve (C3-C5). A T4 injury is too low to cause diaphragmatic paralysis.
Option D: Hand grip is controlled by nerves from the C8 and T1 spinal levels. A T4 injury occurs below this level, so hand function is preserved.

Visual 1: Diagram - A dermatome map of the human body, highlighting the T4 level at the nipple line to show the area of sensory loss.
Visual 2: Illustration - The spinal column with vertebrae labeled, indicating the location of C-spine, T-spine, and L-spine injuries and their corresponding functional impact (tetraplegia vs. paraplegia).

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Clinical manifestations of a T4 spinal cord injury in acute care settings.
Accurate assessment of the injury level is critical for anticipating complications. For a T4 injury, nurses must monitor for signs of autonomic dysreflexia, a medical emergency common with injuries at T6 or above.
While the patient can breathe independently, the paralysis of intercostal muscles impairs coughing, increasing the risk for pneumonia and atelectasis. Nursing care includes encouraging deep breathing and assisted coughing techniques.
What if? - If the injury was at the C4 level instead of T4, the most likely finding would be diaphragmatic paralysis and tetraplegia, requiring immediate and long-term ventilatory support.

How to Approach the Question

First, identify the key information in the stem: a 'complete T4 spinal cord injury'.
Recall the basic anatomy of the spinal cord and the functions controlled by different levels (Cervical, Thoracic, Lumbar).
Remember the key landmarks: C3-C5 for the diaphragm ('C3, 4, 5 keep the diaphragm alive'), C5-T1 for arm and hand function, and Thoracic levels for the trunk and legs.
Evaluate each option against this anatomical knowledge. A T4 injury is thoracic, so it will be below the levels controlling the arms and diaphragm.
Eliminate options related to upper body and breathing deficits. Weakness in the upper extremities (A) or hand (D) points to a cervical injury. Diaphragmatic paralysis (B) points to a high cervical injury.
Conclude that an injury at T4 will affect structures below it, leading to paralysis and sensory loss in the lower extremities.

Concept Tested & Keywords

Concept Tested: Clinical manifestations of a T4 spinal cord injury
Stem keywords: trauma patient, complete T4 spinal cord injury
Lead-in keywords: most likely
Clinical cues: Level of injury: T4 - This is a thoracic injury, which is key to differentiating it from cervical injuries that affect the arms and diaphragm.

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