T8–T9 disc !
The T8-T9 disc is the thin cushion between the T8 and T9 vertebrae in the mid-back; it allows the small movement the ribs permit.
Official name: T8-T9
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What it is
The cushion between T8 and T9: 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 T8 and T9 bodies; thin thoracic disc; head of rib 9 joins it
- Attaches
- Annulus fibrosus anchored to the endplates and ring apophyses of T8 and T9; anterior and posterior longitudinal ligaments
- Function
- Absorbs and spreads load; herniation rare (most at T8–T12), often central onto the cord; lateral herniation may irritate the T8 root
Relations
- In front
- Esophagus moving left and forward, in front of the thoracic aorta; the azygos vein on the right, with the hemiazygos vein crossing behind the aorta to join it at about T9
- Lateral
- Head of rib 9 and its costovertebral joint; the greater splanchnic nerve on the side of the body
How to find it
Not palpable. It is found by counting: up from the 12th rib, or down from the inferior angle of the scapula (about T7); from behind it lies near the tip of the T8 spinous process.
On imaging
Scheuermann disease on a lateral radiograph: three or more adjacent vertebrae each wedged by 5° or more (Sorensen criteria), with irregular endplates and Schmorl nodes.
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
- Pain from this level can be felt in the upper abdomen and mimic gallbladder, pancreatic or stomach disease
- Osteoporotic wedge fractures cluster in the mid-thoracic and thoracolumbar spine; on X-ray the disc keeps its height, which helps separate them from infection, where the disc space is destroyed
Test yourself
Think of the answer, then tap the question to see it.
Which stretch of the thoracic spine, starting at the T8–T9 disc, holds most thoracic disc herniations, and why?
T8–T12: the lower thoracic spine moves more freely than the upper part.
Which radiographic criteria define Scheuermann disease, which peaks around the T8–T9 disc?
Three or more adjacent vertebrae each wedged by 5° or more (Sorensen criteria), with irregular endplates and Schmorl nodes, in a teenager with a rigid round back.
Pain from the T8–T9 disc level can mimic disease of which organs?
Upper abdominal organs: it can be felt in the upper abdomen and mimic gallbladder, pancreatic or stomach disease.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- discus intervertebralis T8-T9 TA2 1684
- Official Spanish (DeCS)
- Disco T8-T9 DeCS D007403
- English (TA2)
- T8-T9
- Also called
- fibrous ring · fibrocartilago intervertebralis
Related
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Back, Intervertebral Discs.
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Representative model, for educational purposes only.
