We investigated the effects of subperiosteal dissection on blood flow in the gluteal medius muscle in adult rabbits using the hydrogen washout technique. Alter the control blood-now rate was determined, 8 rabbits were separated into 2 groups according to the direction of the dissection. The gluteal medius muscle was dissected from the iliac crest in the proximal-distal direction in 10 hips. in another 6 hips, the greater trochanter was osteomised and the gluteus medius muscle was dissected from the ilium in the distal-proximal direction. Dissection of the middle third of the gluteus medius muscle caused the most significant reduction in blood Row, more than 50% in both groups. This result indicates that minimising damage to the mid-portion of the gluteus medius muscle is important for reducing the incidence of post-operative complications.