Answer:
The Mathes-Nahai classification of muscle/musculocutaneous flaps is based on the vascular anatomy:
Type I: a single vascular pedicle (tensor fascia lata)
Type II: a dominant supply with one or multiple minor pedicles (gracilis)
Type III: two dominant pedicles from different vascular sources (gluteus maximus)
Type IV: segmental pedicles (sartorius)
Type V: a dominant supply with a secondary segmental pedicle (latissimus dorsi)
The fasciocutaneous flap classification system:
Type A: direct cutaneous pedicle
Type B: septocutaneous pedicle
Type C: musculocutaneous pedicle (less reliable than type A and B)