Spine and Spinal Cord Disorders
What you must own
Know the anatomy of the spinal column and cord, including the difference between the cord levels and vertebral levels. Understand disc herniation syndromes: cervical (C5/6, C6/7) and lumbar (L4/5, L5/S1), with radicular pain and dermatomal/myotomal correlation. Recognise cauda equina syndrome (saddle anaesthesia, urinary retention, bilateral leg weakness) as a surgical emergency.
Degenerative disease: spondylosis, stenosis, and the concept of neurogenic claudication versus vascular claudication. Trauma: fracture classification and stability. Tumours: extradural (metastasis), intradural extramedullary (meningioma, schwannoma), intramedullary (ependymoma, astrocytoma). Infection: discitis/osteomyelitis and epidural abscess.
Understand the role of MRI (gold standard) and the limits of plain radiographs. Know when surgery is indicated (progressive deficit, cauda equina, instability, infection with cord compression).
Traps
Questions test the distinction between cauda equina (emergency) and conus medullaris syndromes. Another trap: assuming a normal plain radiograph excludes cord compression - MRI is required.
Rule of thumb
Any patient with saddle anaesthesia, urinary retention and bilateral leg symptoms has cauda equina syndrome until proven otherwise - urgent MRI.
Worked example
A patient with a large central L4/5 disc herniation develops urinary retention and saddle numbness. This is cauda equina syndrome requiring emergency decompression, not conservative management.