Anatomical description of the muscles of the pelvic limb in the ostrich (Struthio camelus).

Dissections of 12 formalin-fixed ostriches were performed to give anatomical descriptions of the muscles and tendons of the pelvic, femoral, tibiotarsal, tarsometatarsal and digital regions. In the pelvic limb of the ostrich, 36 muscles can be determined. The ostrich lacks those muscles to the first and second toes (with exception of the M. flexor hallucis longus), which can be found in birds with four toes. The Mm. iliotrochantericus medius, plantaris, extensor proprius digiti IV and adductor digiti IV, which are present in other birds, are also absent, whereas the Mm. pectineus and femorotibialis accessorius additionally occur in the ostrich. The Pars supramedialis is a tendineous part of the M. gastrocnemius, on which the Mm. flexor cruris lateralis and flexor cruris medialis insert by means of a fascial sheet. The caudal part of the M. iliofibularis terminates within the caudal aspect of the superficial fascia cruris. The caudal heads of the Mm. flexor perforatus digiti III and flexor perforatus digiti IV as well as the M. flexor hallucis longus have a common origin on the Fossa poplitea of the femur. The lateral head of the M. flexor perforatus digiti IV and the femoral head of the M. flexor perforans et perforatus digiti III originate on the tendon of origin of the Caput laterale of the M. flexor perforatus digiti III. Furthermore, the last named tendon fuses with the tendon of insertion of the M. ambiens. The M. extensor proprius digiti III originates on a plate-like fascial sheet part of the dorsal joint capsule of the intertarsal joint.