Muscles of the Abdomen

10/23/14

Focus Question: Identifying the muscles of the abdomen: latissimus dorsi, rectus abdominis, external oblique, internal oblique, transverse abdominis and linea alba.

Procedure:

1. Identify the striations of the latissimus dorsi and use the scalpel to cut around and under the latissimus dorsi by cutting through the connective tissue. Do not completely remove the layer of muscle, leave it connected on the side (creating a flap) in order for the incisions and the placement of the different chest muscle to be identified.
2. Take a picture of the incision of the latissimus dorsi. Then take a picture of the flap of muscle folded over.
3. Next identify the linea alba, which is a fibrous structure that runs down the midline (center) of the abdomen. Take a picture of the linea alba.
4. Next move on to identifying the external oblique, which should already be exposed following the skinning process. The external oblique is located on the side of the abdomen of the cat and has striations going at a downward diagonal. Take a picture.
5. Using a scalpel and surgical tweezers, separate the external oblique from the internal oblique, which is directly under the external oblique. The internal oblique has striations going at an upward diagonal. Once separated, leave the external oblique connected on the side of the abdomen near the back, creating a flap. Take a picture of the internal oblique.
6. Using a scalpel and surgical tweezers, separate the internal oblique from the transverse abdominis, which is the deepest layer of the abdominal muscles. The transverse abdominis has striations that go hortionizally across the muscle, like straight lines. Once separated, leave the internal oblique connected on the side of the abdomen near the back, creating a flap. Take a picture of the transverse oblique. Do not cut into the transverse oblique.
7. Next identify the rectus abdominis, which is a straight, sometimes thin line of muscle going up the midline (center) of the cat. Using a scalpel and surgical tweezers, remove any part of the linea alba and any fat in order to clearly identify the rectus abdominis. Once this is done, take a picture of the rectus abdominis.

Materials: Scalpel and surgical tweezers.

Data and Observations:

All of Semara’s abdominal muscles were in great condition and in the correct place. The striations of Semara’s latissimus dorsi were clearly viable. The striations on Semara’s external oblique, internal oblique and transverse abdominis were clearly visible, though these layers of muscle are quite thin, which caused slight difficulty to separate them. Lastly, Semara’s rectus abdominis was fairly thinner than usual making it harder to identify this muscle. Pictures of the data collected are shown below.

Human Corresponding Abdominal Muscles 

Conclusion:

Identifying the muscles of the abdomen was easier than expected. The striations of Semara’s abdominal muscles were more visible which especially helped when identifying the abdominal muscles. I was able to clearly see the difference between the external oblique, the internal oblique and the transverse abdominis. As previously mentioned, it was difficult to separate the abdominal muscles due to how thing they are. I ended up cutting through the internal oblique, leaving is still attached to the external oblique. In other words, instead of having the external oblique and the internal oblique separated, I accidently left them attached. Fortunately, I was still able to identify both muscles even though they weren’t separated. I also struggled to identify the rectus abdominis and ended up cutting through the abdomen while searching for it. None of the internal organs were damaged I just made a faint hole in the abdomen exposing them. I enjoyed studying the abdominal muscles a little bit better than the chest muscles but, the inability to identify the rectus abdominis really irritated me.