Which muscles are among the lowest innervated in a person with a T10 paraplegia?

Which muscles are among the lowest innervated in a person with a T10 paraplegia?

• A. Lower abs and intercostals
• B. Deltoids and biceps
• C. Gastrocnemius and soleus
• D. Gluteus medius and tensor fasciae latae

Answer: (A)

When a spinal injury occurs at T10, the muscles that lose innervation first are the ones supplied by the lowest thoracic nerve roots. The intercostal muscles and the lower part of the anterior abdominal wall get their nerve fibers from the lower thoracic nerves (especially T11–T12). These are the most caudal nerve roots affected by a T10 lesion, so these muscles have the least remaining innervation and are the ones described as the lowest innervated. In contrast, muscles like the deltoid and biceps are supplied by cervical nerves (above the lesion) and would not reflect the same caudal level of innervation loss, and the limb muscles governed by lumbosacral roots are involved but represent different levels of innervation not as close to the lesion as the lower thoracic trunk muscles.

When a spinal injury occurs at T10, the muscles that lose innervation first are the ones supplied by the lowest thoracic nerve roots. The intercostal muscles and the lower part of the anterior abdominal wall get their nerve fibers from the lower thoracic nerves (especially T11–T12). These are the most caudal nerve roots affected by a T10 lesion, so these muscles have the least remaining innervation and are the ones described as the lowest innervated. In contrast, muscles like the deltoid and biceps are supplied by cervical nerves (above the lesion) and would not reflect the same caudal level of innervation loss, and the limb muscles governed by lumbosacral roots are involved but represent different levels of innervation not as close to the lesion as the lower thoracic trunk muscles.