Singh index
The Singh index is a classification system for bone density of the femoral neck based on the visibility of the trabecular types that can be seen in the femoral neck.
Trabecular types in proximal femur
Five trabecular types can be present in the proximal part of the femur:
- principal compression
- secondary compression
- primary tensile
- secondary tensile
- intertrochanteric
As osteoporosis progresses these trabeculae get thinner and eventually disappear.
Singh index
- grade 1: only thin principal compression trabeculae visible
- grade 2: principle compression trabeculae present, other trabeculae nearly resorbed
- grade 3: principle tensile trabeculae thinned and breakage in continuity present
- grade 4: principal tensile trabeculae thinned without loss of continuity
- grade 5: principle tensile and compression trabeculae readily visible with prominence of Ward triangle
- grade 6: all trabeculae visible and of normal thickness
Grade 3 and below indicate definite osteoporosis.
