## Fracture Classification by Line Pattern **Key Point:** A spiral fracture is defined by a **helical or corkscrew pattern** of the fracture line that wraps around the bone shaft, caused by **rotational (torsional) forces**. ### Mechanism and Characteristics Spiral fractures result from: 1. **Torsional (twisting) force** applied to the bone 2. Fracture line spirals around the bone axis 3. Creates a characteristic helical pattern on radiographs 4. Often associated with significant soft tissue injury 5. Common in long bones (femur, tibia, humerus) ### Comparison of Fracture Line Patterns | Pattern | Angle to Axis | Force Type | Typical Location | Stability | | --- | --- | --- | --- | --- | | **Transverse** | 90° (perpendicular) | Bending/shear | Diaphysis | Unstable | | **Oblique** | 45–60° | Bending + compression | Diaphysis | Moderately unstable | | **Spiral** | Helical/corkscrew | Torsion/rotation | Diaphysis | Unstable, soft tissue damage | | **Longitudinal** | Parallel to axis | Tension/splitting | Metaphysis | Variable | **High-Yield:** Spiral fractures are: - **High-energy injuries** with significant soft tissue trauma - **Prone to nonunion** if not rigidly fixed - **Require surgical fixation** (intramedullary nailing or plate fixation) - **Associated with compartment syndrome** risk **Clinical Pearl:** In children, a spiral fracture of the femur or tibia should raise suspicion for **non-accidental injury (NAI)** or child abuse, as the mechanism (twisting force) is difficult to explain in accidental falls. **Mnemonic:** **SPIRAL = SPIN/TWIST** — visualize the fracture line spiraling around the bone like a barber pole when torsional force is applied. 
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.