A patient with a thoracic-level spinal cord injury presents with an intact light touch and pinprick at S4-S5, voluntary anal contraction, and motor function grade ≥3 in all key muscles below the neurological level. What is their AIS classification?

A patient with a thoracic-level spinal cord injury presents with an intact light touch and pinprick at S4-S5, voluntary anal contraction, and motor function grade ≥3 in all key muscles below the neurological level. What is their AIS classification?

• A. AIS A
• B. AIS B
• C. AIS C
• D. AIS D

Answer: (D)

Focus on how AIS distinguishes levels of motor preservation below the injury. The key point is whether motor function is preserved below the neurological level and, if so, how much of that preserved motor function there is. This patient has preserved motor function below the neurological level with every key muscle below that level testing at least a 3 out of 5. That means more than half of the key muscles below the level are functioning at a useful strength, which places the injury in the D category. The sacral sparing—intact sensation to light touch and pinprick at S4-S5 and a voluntary anal contraction—confirms the injury is not complete (not AIS A) and supports an incomplete status. But the decisive factor here is the motor preservation pattern below the level: all key muscles below are ≥3, which aligns with AIS D.

Focus on how AIS distinguishes levels of motor preservation below the injury. The key point is whether motor function is preserved below the neurological level and, if so, how much of that preserved motor function there is.

This patient has preserved motor function below the neurological level with every key muscle below that level testing at least a 3 out of 5. That means more than half of the key muscles below the level are functioning at a useful strength, which places the injury in the D category. The sacral sparing—intact sensation to light touch and pinprick at S4-S5 and a voluntary anal contraction—confirms the injury is not complete (not AIS A) and supports an incomplete status. But the decisive factor here is the motor preservation pattern below the level: all key muscles below are ≥3, which aligns with AIS D.