Left cerebral hemisphere

Function

Each cerebral hemisphere is a folded sheet of cortex — 2–4 mm thick and about 1,200 cm² in area (≈2,500 cm² for both hemispheres), pressed into gyri and sulci to fit the skull. Beneath the cortex, white matter fibres arc as association bundles, commissures and projection fibres, while deep nuclei (basal ganglia, thalamus) coordinate movement and gating.

The left hemisphere in most people hosts Broca's and Wernicke's language areas, analytical sequence processing and fine motor control of the right body. Four lobes divide its labour: frontal (executive function and movement), parietal (somatosensation and spatial maps), temporal (hearing and memory) and occipital (vision).

Blood supply

Internal carotid → middle and anterior cerebral arteries.

Nerve supply

Not applicable — brain tissue has no pain receptors; the meninges around it are supplied by the trigeminal and upper cervical nerves.

Clinical relevance

Stroke — middle cerebral artery

Left MCA occlusion causes right hemiparesis, right sensory loss and aphasia — the constellation every stroke physician drills.

Traumatic contusion

The frontal and temporal poles strike the skull's inner ridges in acceleration injury — contusions bleed slowly and swell.

Related conditions

• Stroke
• Transient ischaemic attack (mini-stroke)
• Migraine
• Epilepsy
• Alzheimer's disease
• Parkinson's disease
• Multiple sclerosis
• Meningitis
• Brain tumours (glioma)
• Subarachnoid haemorrhage
• Bell's palsy
• Concussion (mild traumatic brain injury)
• Depression
• Anxiety disorders
• Bipolar disorder
• Schizophrenia
• Post-traumatic stress disorder
• Attention deficit hyperactivity disorder
• Autism spectrum disorder
• Eating disorders (anorexia and bulimia)