1. Myomere 2. Epaxial 3. Horizontal Septum 4. Myoseptum 5. Hypaxial 6. Cloaca

1. Abductor (Extensor) 2. Pectoral Fin

1. Adductor (Flexor) 2. Pectoral Fin

    The musculature system of fishes consist mainly of epaxial, hypaxial, abductor, and adductor muscles. The epaxial and hypaxial muscles are made up of myomeres (muscle blocks) that are divided by myosepta which are sheets of connected tissue that are found between each myomere (Fishbeck and Sebastiani 2001). The epaxial and hypaxial muscles are divided with a different sheet of connected tissue called the horizontal septum. These muscles allow lateral movement for locomotion. Abductor muscles are muscles that can move an appendage away from the body, as with the pectoral fin abductor labelled in the picture above. The adductor muscle works opposite. It can move an appendage closer to the body.