Sympathetic trunk

Looks like

A beaded nerve cord running on each side of the spine from the skull base to the tailbone.

What it does

Distributes 'fight or flight' control to the whole body.

Keeping it well

Damage in the neck or upper chest (e.g. lung-apex tumour) causes Horner syndrome — a small pupil and droopy lid need a doctor.

Related conditions

• Amyloidosis (AL and ATTR)
• Botulism
• Chickenpox (varicella)
• Chronic neuropathic pain
• Chronic pain syndrome
• Fibromyalgia
• Guillain-Barré syndrome
• Lyme disease
• Myasthenia gravis
• Neuroblastoma
• Peripheral neuropathy
• Rabies
• Restless legs syndrome
• Shingles (herpes zoster)
• Tetanus
• Vitamin B1, C and other deficiencies