Which is the most common site of spinal cord injury in adults?

Explanation

## Most Common Site of Spinal Cord Injury ### Epidemiology of Spinal Cord Injury **Key Point:** The cervical spine, particularly C5–C6, is the most frequent site of traumatic spinal cord injury in adults, accounting for approximately 50–60% of all cases. ### Anatomical Vulnerability **High-Yield:** The cervical region is most vulnerable because: 1. It has the greatest mobility and least muscular support 2. It bears the weight of the head during flexion–extension trauma 3. Motor vehicle accidents and falls from height commonly cause hyperextension or hyperflexion at this level 4. The vertebral bodies are smaller and more susceptible to fracture-dislocation ### Mechanism of Injury at C5–C6 **Clinical Pearl:** Hyperextension injuries (e.g., from motor vehicle collisions, falls) preferentially injure the cervical cord because the spinal canal narrows posteriorly during extension, compressing the cord between the posterior vertebral body and ligamentum flavum. ### Comparison of Injury Sites | Region | Frequency (%) | Common Mechanism | Neurological Pattern | | --- | --- | --- | --- | | Cervical (C5–C6) | 50–60 | Hyperextension, flexion–distraction | Tetraplegia, respiratory compromise | | Thoracolumbar (T12–L1) | 35–40 | Flexion, compression, shear | Paraplegia | | Lumbar (L4–L5) | 5–10 | Burst fractures, falls | Cauda equina syndrome | | Sacral (S1–S2) | <5 | Pelvic trauma | Sacral nerve root injury | **Warning:** The thoracolumbar junction (T12–L1) is the second most common site because it is the transition zone between the rigid thoracic spine and the mobile lumbar spine, creating a biomechanical stress point. ### Why Cervical Injury Is Most Common 1. **Mobility:** The cervical spine has the greatest range of motion, making it more prone to traumatic displacement. 2. **Leverage:** The head acts as a lever arm during trauma, concentrating forces at the cervical level. 3. **Accident patterns:** Motor vehicle accidents and falls commonly cause cervical injury because the head and neck are exposed during impact. 4. **Smaller vertebrae:** Cervical vertebral bodies are smaller and have less load-bearing capacity than thoracic or lumbar vertebrae. **Mnemonic:** **CHAMP** — **C**ervical (most common), **H**yperextension (mechanism), **A**ccidents (MVA, falls), **M**obility (greatest range), **P**aralysis (tetraplegia).