Nervous system · Head and neck
Red nucleus !
The red nucleus is a round cluster of cells in the midbrain; it relays movement signals between the cerebellum and the brain's cortex.
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What it is
A round nucleus in the midbrain.
What it does
Relays motor signals between the cerebellum and the cortex.
Key facts
- Where
- Midbrain tegmentum, at the level of the superior colliculus
- Blood supply
- Paramedian branches of the posterior cerebral artery
- Function
- Motor relay between the cerebellum (dentate nucleus) and the cortex; gives the rubrospinal tract
Relations
- In front
- Substantia nigra (anterolaterally) and the cerebral peduncle
- Behind
- Tegmentum and the periaqueductal grey around the cerebral aqueduct, at the level of the superior colliculi
- Medial
- Oculomotor nerve fibres running forward through and beside it toward the interpeduncular fossa
- Lateral
- Medial lemniscus
- Course
- Input: crossed fibres of the superior cerebellar peduncle from the opposite dentate nucleus, and the motor cortex. Output: rubrospinal tract (crossed) and the central tegmental tract to the inferior olivary nucleus
How to find it
On an axial cut at the level of the superior colliculi it is a round mass in the tegmentum, behind and medial to the substantia nigra, crossed by oculomotor nerve fibres on their way to the interpeduncular fossa. On T2-weighted MRI it looks dark from its iron content.
On imaging
Rich in iron, so on T2 and susceptibility MRI it looks dark (hypointense), like the substantia nigra; the iron also gives fresh tissue its pinkish colour.
Clinical notes
- Holmes (rubral) tremor: a slow, coarse tremor present at rest, on posture and on movement, after midbrain lesions that interrupt the cerebellar outflow near the red nucleus
- Claude syndrome: a slightly more dorsal tegmental lesion gives an oculomotor palsy with opposite-side cerebellar ataxia
Memory aid
deCORticate: the hands are drawn toward the 'cor' (heart); decErebrate: everything is Extended.
Related conditions
Test yourself
Think of the answer, then tap the question to see it.
What is Benedikt syndrome?
A tegmental midbrain lesion through the red nucleus and oculomotor fibres: oculomotor palsy on the same side and tremor or involuntary movements of the opposite limbs.
How do decorticate and decerebrate postures relate to the red nucleus?
Lesion above the red nucleus: decorticate (arms flexed, legs extended); below it: decerebrate (all limbs extended), the worse sign.
Which three structures form the Guillain–Mollaret triangle, and what does a lesion cause?
Dentate nucleus, red nucleus and inferior olivary nucleus; a lesion causes palatal tremor.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- nucleus ruber TA2 5898
- Official Spanish (DeCS)
- Núcleo Rojo DeCS D012012
- English (TA2)
- Red nucleus
Related
Sources: Terminologia Anatomica (TA2); DeCS; Neuroanatomy, Red Nucleus.
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Representative model, for educational purposes only.
