Thoracic Anatomy & Biomechanics - Thoracic Framework
- 12 vertebrae (T1-T12); form natural kyphosis (20-40°).
- Articulates with ribs via costovertebral & costotransverse joints, creating stable thoracic cage.
- Vertebral bodies: typically heart-shaped; size ↑ inferiorly.
- Spinous processes: long, point downwards, overlap vertebra below.
- Facet joints: oriented near coronal plane; primary motion: rotation; limited flexion/extension.
- Intervertebral discs: relatively thin, contributing to regional stiffness.
⭐ Rule of 3s for spinous process alignment (T1-3 same level, T4-6 half below, T7-9 full level below, T10 full, T11 half, T12 same).
Thoracic Trauma - Thoracic Thwacks
- Mechanism: High-energy (MVA, fall). Rigid thoracic spine means injury implies high force.
- Presentation: Severe pain, tenderness, deformity. Neurological deficit frequent & severe.
⭐ Neurological deficit is more common and severe in thoracic spine injuries due to the narrow spinal canal and tenuous blood supply.
- Imaging: X-ray, CT (bone detail), MRI (cord, PLC).
- TLICS Score: Guides management.
- Morphology: Compression (1), Burst (2), Translation/Rotation (3), Distraction (4).
- Neurological: Intact (0), Root (2), Incomplete Cord (3), Complete Cord (2).
- PLC Integrity: Intact (0), Indeterminate (2), Injured (3).
- Total Score: <4 (Non-op), 4 (Variable), >4 (Operative).
Thoracic Deformities - Curved Columns
- Scoliosis: Lateral spinal curvature $Cobb > 10°$.
- Types: Idiopathic (most common, esp. adolescent girls), Congenital, Neuromuscular.
- Signs: Shoulder/hip asymmetry, rib hump on Adam's forward bend test.
- Treatment: Observation ($10-25°$), Bracing ($25-45°$ in skeletally immature), Surgery ($>45-50°$ or progressive).
- Kyphosis: Exaggerated posterior thoracic curvature.
- Scheuermann's Disease: Rigid kyphosis $>45°$, anterior vertebral wedging $≥5°$ in $≥3$ consecutive vertebrae, Schmorl's nodes. Often in adolescent males.
- Other Types: Postural (flexible), Congenital (vertebral defects), Post-traumatic.
- Treatment (Scheuermann's): Exercises, Brace (if progressive/painful, Risser < extbf{4}), Surgery ($>75°$, refractory pain, neuro deficit).
⭐ Adam's forward bend test is key for detecting rotational deformity (rib hump) in idiopathic scoliosis.
Thoracic Infections & Tumors - Spine Invaders
- Red flags: Night pain, weight loss, neuro deficits. Hematogenous spread common.
| Condition | Key Features | Imaging |
|---|---|---|
| Pott's Spine (TB) | Insidious, night pain, constitutional sx, late neuro deficit. | Anterior body, disc ↓, paraspinal shadow, kyphosis. |
| Metastasis | Known primary, severe pain (night↑), early neuro deficit. | Lytic/blastic, pedicle erosion ("winking owl"). |
| Multiple Myeloma | Elderly, bone pain, fractures, renal failure, anemia. | Osteopenia, "punched-out" lytic lesions. |
⭐ Pott's spine (TB) typically affects the anterior vertebral body and intervertebral disc, leading to vertebral collapse, kyphosis, and potential cold abscess formation.
High‑Yield Points - ⚡ Biggest Takeaways
- Scheuermann's disease: Rigid thoracic kyphosis in adolescents, anterior vertebral wedging (≥5°, ≥3 vertebrae).
- Pott's spine (TB): Thoracolumbar junction most common; paradiscal lesions, cold abscess, potential neurological deficit.
- Thoracic disc herniation: Rare; often presents with myelopathy or radicular pain.
- Adolescent Idiopathic Scoliosis (AIS): Most common; use Cobb angle. Bracing for 25-45° curves if immature.
- Osteoporotic compression fractures: Common; consider vertebroplasty/kyphoplasty for severe pain.
- Spinal Metastases: Most common spinal tumors; thoracic spine frequently involved, often causing pain.
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