T5–T6 disc !
The T5-T6 disc is the thin cushion between the T5 and T6 vertebrae in the mid-back; it allows the small movement the ribs permit.
Official name: T5-T6
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What it is
The cushion between T5 and T6: a tough outer ring of fibres (annulus fibrosus) around a soft centre.
What it does
Absorbs load and allows the small amount of movement the rib cage permits.
Key facts
- Where
- Between T5 and T6 bodies; thin thoracic disc; head of rib 6 joins it
- Attaches
- Annulus fibrosus anchored to the endplates and ring apophyses of T5 and T6; anterior and posterior longitudinal ligaments
- Function
- Absorbs and spreads load; herniation rare, often central onto the cord; lateral herniation may irritate the T5 root
Relations
- In front
- Thoracic aorta on the left front of the bodies, esophagus in the midline, the azygos veins on the right, and the thoracic duct between the aorta and the azygos vein
- Lateral
- Head of rib 6 on the disc and its costovertebral joint; the sympathetic trunk on the rib heads, giving the first roots of the greater splanchnic nerve (from about T5)
- Behind
- Posterior longitudinal ligament, a thin epidural space and the spinal cord
How to find it
It has no landmark of its own: it is found by counting up from the inferior angle of the scapula (about T7) or down from C7. From behind it lies roughly level with the tip of the T5 spinous process.
On imaging
When MRI cannot be done, CT myelography shows a mid-thoracic disc as a dent in the contrast column in front of the cord; plain CT adds whether the disc is calcified, which shapes the choice of route.
Common problems
- Thoracic disc herniations are uncommon; many are found by chance on MRI and cause no symptoms.
- A large one can press on the spinal cord, or cause band-like pain around the chest.
How it is diagnosed
MRI; CT shows whether the herniation is calcified (hardened), which matters for surgery.
Treatment
- Usually physical therapy and pain medicine; surgery only if the spinal cord is pressed.
Clinical notes
- Routes go around the side of the cord: posterolateral (transpedicular, costotransversectomy), retropleural or thoracoscopic, chosen by whether the disc is central, lateral or calcified
- Thoracic disc herniations are often found on MRI in people with no symptoms; one is blamed only when its level fits the band of pain or the cord signs
Test yourself
Think of the answer, then tap the question to see it.
Why can modest compression at the T5–T6 disc cause myelopathy?
It is the centre of the mid-thoracic vascular watershed: the cord relies on a thin anterior spinal artery with few feeders.
Why is a central disc herniation at T5–T6 not removed through a laminectomy alone?
Reaching it from behind would mean retracting the spinal cord, which historically caused paralysis; routes go around the side of the cord.
Which nerve takes its first roots from the sympathetic trunk at about the level of the T5–T6 disc?
The greater splanchnic nerve, from about T5.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- discus intervertebralis T5-T6 TA2 1684
- Official Spanish (DeCS)
- Disco T5-T6 DeCS D007403
- English (TA2)
- T5-T6
- Also called
- fibrous ring · fibrocartilago intervertebralis
Related
Sources: Terminologia Anatomica (TA2); DeCS; 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.
