Anatom3DSubarachnoid space
Spatium subarachnoideum · Subarachnoidální prostor
Nervous system
Looks like
A fluid-filled gap between the arachnoid and pia, surrounding the brain and spinal cord.
What it does
Holds cerebrospinal fluid that cushions the brain; the major brain arteries run through it.
Keeping it well
A burst aneurysm bleeds here: a sudden 'worst headache of my life' reaching its peak within a minute needs an ambulance.
Related conditions
- Acute liver failure
- ADHD
- African trypanosomiasis (sleeping sickness)
- Alcohol withdrawal and delirium tremens
- Altitude sickness
- Alzheimer's disease
- Amyloidosis (AL and ATTR)
- Autism spectrum disorder
- Bipolar disorder
- Birth asphyxia (hypoxic-ischaemic encephalopathy)
- Body dysmorphic disorder
- Botulism
- Brain abscess
- Brain aneurysm
- Brain tumour (glioma & meningioma)
- Cerebral palsy
- Chickenpox (varicella)
- Chronic insomnia
- Chronic neuropathic pain
- Chronic pain syndrome
- Cluster headache
- Concussion (mild TBI)
- Congenital hypothyroidism
- Cryptococcal meningitis
- Delirium
- Down syndrome (trisomy 21)
- Drowning
- Eating disorders
- Encephalitis
- Epilepsy
- Essential tremor & dystonia
- Fainting (syncope)
- Febrile seizures
- Fibromyalgia
- Fragile X syndrome
- Frailty & falls in older age
- Functional (somatic) symptom disorder
- Generalised anxiety disorder
- Guillain-Barré syndrome
- Haemorrhagic stroke
- Heat exhaustion & heatstroke
- Hepatic encephalopathy
- Huntington's disease
- Hydrocephalus
- Hypoglycaemia (low blood sugar)
- Idiopathic intracranial hypertension
- Intellectual disability
- Ischaemic stroke
- Japanese encephalitis
- Lead poisoning
- Long COVID (post-viral syndrome)
- Lyme disease
- Major depressive disorder
- ME/chronic fatigue syndrome
- Measles
- Medication-overuse headache
- Meningitis
- Migraine
- Multiple sclerosis
- Mumps
- Myasthenia gravis
- Narcolepsy
- Neonatal sepsis
- Neurocysticercosis
- Normal pressure hydrocephalus
- Parkinson's disease
- Peripheral neuropathy
- Phenylketonuria (PKU)
- Poisoning & overdose
- Post-traumatic stress disorder
- Postnatal depression
- Postpartum psychosis
- Rabies
- Restless legs syndrome
- Roseola (sixth disease)
- Schizophrenia
- Self-harm and suicidal crisis
- Shingles (herpes zoster)
- Spina bifida & neural tube defects
- Subdural haematoma
- Substance use disorder
- Tension-type headache
- Tetanus
- Thrombotic thrombocytopenic purpura (TTP)
- Tick-borne encephalitis
- Tics and Tourette syndrome
- Toxoplasmosis & CMV
- Transient ischaemic attack
- Traumatic brain injury (moderate to severe)
- Tuberous sclerosis complex
- Vascular dementia
- Vitamin B1, C and other deficiencies