Thoracolumbar spinal cord (T3-L3)

Disease in this region of the spinal cord typically causes signs of UMN dysfunction in the pelvic limbs and normal thoracic limbs.

Common clinical signs of thoracolumbar (T3-L3) myelopathy

  • Spastic weakness/paralysis and ataxia in pelvic limbs
  • Normal to exaggerated spinal nerve reflexes in pelvic limbs
  • Normal withdrawal reflexes in the pelvic limbs
  • Postural reaction deficits in pelvic limbs
  • Late onset disuse muscle atrophy
  • +/- Decreased or absent cutaneus trunci reflex (lesion is usually 1-2 vertebrae cranial to cutoff)
  • +/- Paravertebral pain at site of lesion
  • +/- UMN bladder
  • +/- Schiff-Sherrington posture

Case example of a Pekingese with a T12-13 intervertebral disc extrusion causing thoracolumbar (T3-L3) signs.

TIP: To help decide whether a patient has UMN signs to all 4 limbs (C1-C5) or Schiff-Sherrington posture with a T3-L3 myelopathy, closely evaluate the postural reactions in the thoracic limbs. With support, a patient with Schiff-Sherrington posture will usually  be able to walk (albeit stiffly) and have normal postural reactions in the thoracic limbs, while a patient with a C1-C5 lesion  have difficulty walking and will have delayed or absent postural reactions. Obviously, the presence of thoracic or lumbar discomfort would suggest Schiff-Sherrington while cervical discomfort/rigidity would suggest a C1-C5 lesion.