Filum terminale

Looks like

A thread of pia mater, about 20 cm long, running down from the tip of the spinal cord through the fluid-filled sac and on to the back of the coccyx.

What it does

Anchors the lower end of the cord and holds it steady inside the canal as the spine bends.

Keeping it well

A thick, fatty or short filum tethers the cord (tethered cord syndrome): back pain, leg weakness, foot deformity and bladder trouble, often with a skin mark over the lower back; cutting the filum releases it.

Related conditions

• Amyloidosis (AL and ATTR)
• Amyotrophic lateral sclerosis
• B12 & folate deficiency
• Bone metastases and spinal cord compression
• Botulism
• Chiari malformation and syringomyelia
• Chickenpox (varicella)
• Chronic neuropathic pain
• Chronic pain syndrome
• Fibromyalgia
• Friedreich's ataxia
• Guillain-Barré syndrome
• Lyme disease
• Multiple sclerosis
• Myasthenia gravis
• Neck pain and cervical spondylosis
• Neurogenic bladder
• Neuromyelitis optica spectrum disorder
• Peripheral neuropathy
• Poliomyelitis
• Rabies
• Restless legs syndrome
• Shingles (herpes zoster)
• Spina bifida & neural tube defects
• Spinal cord injury
• Spinal muscular atrophy
• Tetanus
• Tick-borne encephalitis
• Vitamin B1, C and other deficiencies