Angle formed by joining a line extended from fracture line of fracture neck to an arbitrary line depicting horizontal plane
**Core Concept**
The angle formed by joining a line extended from the fracture line of the fracture neck to an arbitrary line depicting the horizontal plane is a measure used in orthopedic surgery to assess the stability and displacement of hip fractures, particularly in the context of fracture neck of the femur. This angle is critical in evaluating the severity of the fracture and guiding treatment decisions.
**Why the Correct Answer is Right**
The angle in question is the "Hill-Sachs angle," which is a radiographic measurement used to assess the degree of posterior wall impaction in femoral neck fractures. The Hill-Sachs lesion is a compression fracture of the posterolateral aspect of the humeral head, but in the context of femoral neck fractures, the angle formed is used to estimate the extent of posterior displacement. The normal angle is typically around 10-20°, and values exceeding 30-40° indicate significant posterior wall impaction.
**Why Each Wrong Option is Incorrect**
**Option A:** This is not a recognized angle in orthopedic trauma. The correct term is the Hill-Sachs angle.
**Option B:** This option is incorrect as it does not relate to the assessment of hip fractures or the measurement of posterior wall impaction.
**Option C:** This is a distractor related to a different orthopedic condition, specifically a fracture of the humeral head.
**Clinical Pearl / High-Yield Fact**
The Hill-Sachs angle is an important radiographic finding that can help predict the risk of post-traumatic hip dislocation and guide treatment decisions for femoral neck fractures.
**Correct Answer: D. Hill-Sachs angle**