T1–T2 nucleus !
The nucleus pulposus is the soft, gel-like centre of the T1-T2 disc in the mid-back; it works like a water cushion that spreads the load.
Official name: T1-T2
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What it is
The soft, gel-like centre (nucleus pulposus) of the T1–T2 disc.
What it does
Works like a water cushion: it turns pressure from above into outward push on the fibre ring, spreading the load. It is under the most pressure when you bend forward and lift.
Key facts
- Where
- Centre of the T1–T2 disc, slightly toward the back, inside the annulus fibrosus
- Function
- Notochord-derived gel (about 70–90% water, proteoglycans); turns axial load into annulus tension; small in thin thoracic discs, herniation rare
Relations
- Behind
- Thin back of the annulus fibrosus and the posterior longitudinal ligament, then the spinal cord; the T1 root lies behind and to the side
Examination
- T1 root: finger spreading against resistance (interossei) is weak and the inner arm near the elbow is numb
On imaging
Axial T2 MRI through T1–T2 shows whether a fragment has moved into the foramen toward the T1 root; plain films are of little help, as the shoulders overlap this level.
Common problems
- Squeezes out through a tear in the ring (herniation), usually backward and to one side, toward a nerve root.
- Loses water with age, so the disc gets thinner and stiffer.
How it is diagnosed
On MRI a healthy nucleus is bright on T2 images; a worn one turns dark ('black disc').
Treatment
- In a microdiscectomy only the loose piece that has pushed out is removed; most of the disc stays.
Clinical notes
- A T1 root lesion may come with Horner syndrome on the same side (small pupil, drooping lid), since sympathetic fibres for the head leave the cord through T1
- An apical lung (Pancoast) tumour produces the same hand weakness and Horner picture and is ruled out on imaging
Test yourself
Think of the answer, then tap the question to see it.
Which root can a posterolateral fragment of the T1–T2 nucleus reach, and what is special about it?
The T1 root, the only thoracic root that supplies the hand.
Which imaging shows a T1–T2 nucleus fragment moving toward the T1 root?
Axial T2 MRI through T1–T2; plain films help little, as the shoulders overlap this level.
What is the T1–T2 nucleus pulposus made of?
A notochord-derived gel, about 70–90% water held by proteoglycans.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- nucleus pulposus T1-T2 TA2 1686
- Official Spanish (DeCS)
- Núcleo pulposo T1-T2 DeCS D000070614
- English (TA2)
- T1-T2
Related
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Back, Nucleus Pulposus; Anatomy, Back, Intervertebral Discs; 7.3 The Vertebral Column (OpenStax (Rice University), 2022) · adapted, CC BY 4.0.
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Representative model, for educational purposes only.
