Skin the left side of the thorax and abdomen: Make an incision through the skin along the dorsal midline from the withers to the level of the sacrum. From the sacrum make a ventral skin incision. Carefully separate the skin from the cutaneus trunci muscle. Leave the skin attached ventrally.

Remove fat tissue from the cutaneus trunci and cutaneus omobrachialis muscles to reveal their fiber directions: dorso-ventral for the cutaneus omobrachilis muscle and caudodorsal for the cutaneus trunci muscle.