Reflect the cutaneus omobrachialis and cutaneus trunci muscles. Cut the tendenous tissue near the dorsal midline and lift the muscle off the fatty layer beneath. Continue ventrally to approach the ventral midline.

Some fat may have peeled off with the muscle but most of it is left on the trunk. This fat separates fairly easily from the muscles below aided by pulling and scoring with a sharp knife. The following muscles will appear: cervical and thoracic parts of the trapezius muscle, latissimus dorsi muscle, supraspinatus, infraspinatus, deltoideus, serratus ventralis thoracis muscle, serratus dorsalis caudalis, external intercostal, external abdominal oblique, and pectoralis profundus ascendens muscles (Popesko: figure 124).

Some of these muscles are covered by thick layers of fascia obscuring muscle fiber direction. A significant portion of the fascia can be removed by holding it with rat toothed forceps and careful slicing motion with a sharp knife. The scalpel is preferred to remove the fat out of valleys created by the ribs and various muscles. It is important not to clean too much caudally at this time as it is easy to remove the caudaodorsal attachments of the external abdominal oblique muscle - do not enter the abdomen.