Pituitary stalk

Looks like

The thin stalk (infundibulum) hanging the pituitary from the hypothalamus through a gap in the dura, just behind the optic chiasm.

What it does

Carries nerve fibres that deliver ADH and oxytocin to the posterior lobe, and tiny portal veins that bring the hypothalamus's releasing hormones to the anterior lobe.

Keeping it well

A cut or squeezed stalk (head injury, tumour, surgery) causes diabetes insipidus and high prolactin, because dopamine no longer reaches the gland. A thickened stalk on MRI needs looking into — inflammation, sarcoid or histiocytosis.

Related conditions

• Absent periods (amenorrhoea)
• Acute liver failure
• ADHD
• Adrenal insufficiency (Addison's)
• African trypanosomiasis (sleeping sickness)
• Alcohol withdrawal and delirium tremens
• Altitude sickness
• Alzheimer's disease
• Autism spectrum disorder
• Bipolar disorder
• Birth asphyxia (hypoxic-ischaemic encephalopathy)
• Body dysmorphic disorder
• Brain abscess
• Brain aneurysm
• Brain tumour (glioma & meningioma)
• Cerebral palsy
• Chronic insomnia
• Chronic neuropathic pain
• Chronic pain syndrome
• Cluster headache
• Concussion (mild TBI)
• Congenital hypothyroidism
• Cryptococcal meningitis
• Cushing's syndrome
• Delirium
• Diabetes insipidus (arginine vasopressin deficiency)
• Down syndrome (trisomy 21)
• Drowning
• Early puberty (precocious puberty)
• 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
• Haemorrhagic stroke
• Heat exhaustion & heatstroke
• Hepatic encephalopathy
• High prolactin (hyperprolactinaemia)
• Huntington's disease
• Hydrocephalus
• Hyperthyroidism & Graves' disease
• Hypoglycaemia (low blood sugar)
• Hypopituitarism
• Hypothyroidism
• Intellectual disability
• Ischaemic stroke
• Japanese encephalitis
• Lead poisoning
• Long COVID (post-viral syndrome)
• Major depressive disorder
• ME/chronic fatigue syndrome
• Measles
• Medication-overuse headache
• Meningitis
• Menopause & perimenopause
• Migraine
• Multiple sclerosis
• Narcolepsy
• Neurocysticercosis
• Normal pressure hydrocephalus
• Parkinson's disease
• Phenylketonuria (PKU)
• Pituitary adenoma
• Poisoning & overdose
• Polycystic ovary syndrome
• Post-traumatic stress disorder
• Postnatal depression
• Postpartum psychosis
• Rabies
• Roseola (sixth disease)
• Schizophrenia
• Self-harm and suicidal crisis
• Subdural haematoma
• Substance use disorder
• Tension-type headache
• 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
• Type 1 diabetes
• Vascular dementia