Table II.
Muscle diameter, CSA, and fatty infiltration of the 18 hip muscles were assessed on axial MR views at four different levels and two different sagittal views.
| Muscle | Plane | Level/position | Description of diameter measurement | Description of CSA measurement | Figure |
|---|---|---|---|---|---|
| Gluteus maximus | Axial | Femoral head center | Maximum radial diameter | n.a. | 5 |
| Gluteus medius | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Gluteus minimus | Axial | Acetabular roof | Maximum diameter | Maximum CSA | 4 |
| Tensor fasciae latae | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Sartorius | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Rectus femoris, direct head | Axial | Ischial tuberosity | Maximum diameter | Maximum CSA, without tendinous portion | 6 |
| Rectus femoris, indirect head | Axial | Acetabular roof | Intactness of the tendinous insertion | n.a. | 4 |
| Vastus lateralis | Axial | Ischial tuberosity | Maximum diameter | Maximum CSA | 6 |
| Psoas | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Iliacus | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Iliocapsularis | Axial | Femoral head center | Maximum radial diameter | Maximum CSA | 5 |
| Obturator internus | Axial | Femoral head center | Maximum radial diameter | Maximum CSA, without tendinous portion | 5 |
| Obturator externus | Sagittal | Transverse ligament | Maximum diameter | Maximum CSA | 8 |
| Piriformis | Axial | Sciatic notch | Maximum diameter | Maximum CSA | 3 |
| Gemellus superior | Sagittal | Lateral ¼ of femoral head | Maximum horizontal diameter | Maximum CSA | 7 |
| Gemellus inferior | Sagittal | Lateral ¼ of femoral head | Maximum horizontal diameter | Maximum CSA | 7 |
n.a., not applicable.