An experimental study was planned to examine whether the blood supply of muscle would be maintained by reverse flow from the cutaneous arteriolar microcirculatory system via the musculocutaneous perforators. A flap model containing both muscle and skin based on the inferior superficial epigastric vessels was designed with the blood supplied directly from the cutaneous arteriolar microcirculatory system, A total of 154 male Wistar Albino rats were divided into three groups. Group I included the standard vertical rectus abdominis musculocutaneous flap based on the superior deep epigastric vessels (N = 48), Group II included the acute cutaneous muscle flap (N = 53). Group III contained the delayed cutaneous muscle flap (N = 53). Skin flap survival area, muscle scintigraphy with technetium-99m-methoxy-isobutyl-isonitrile, microangiography, and histopathological examination of the flaps were conducted. The mean percentage of surviving skin paddle area was 96.4 +/- 5.2%, 84.9 +/- 21.6%, and 91.0 +/- 16.8% in groups I, II, and III respectively. There was no significant difference between groups. Microangiography revealed the blood,flow from skin to muscle through the musculocutaneous perforators. The radioisotope uptake of the muscle flap was expressed as A percentage of the intact contralateral muscle. Mean uptake in group I was 90.1 +/- 4.9% immediately after flap elevation, 62.5 +/- 13.5% on day 2, and 88.3 +/- 12.0% on day 7, These values were 53.7 +/- 7.1%, 63.6 +/- 14,1%, and 89.2 +/- 18.1% in group II, and 64 +/- 7.8%, 75.5 +/- 9.8%, and 92.8 +/- 40:1% in group III. Radioisotope uptake in group I was significantly higher than groups II and III immediately after flap elevation (p < 0,05, analysis of variance), whereas there was no significant difference on days 2 and 7. Histopathological examination revealed surviving muscle tissue without marked atrophy. There was no marked difference between groups histopathologically. These results indicate that muscle tissue may survive by reverse how through the musculocutaneous perforators when elevated with an axial skin flap.