It's All ... Lizard to Me?

This week in the lab was ... not as productive as hoped. On Tuesday, I got a lot done. All the of the superficial muscles on my iguana were removed and weighed, revealing the deeper muscles below. Taking the muscles off was pretty simple. The hardest part was ensuring that the cut was made as close to the bone as possible. Because I am weighing the muscles for comparative purposes, it it important for the entire muscle to come off, and not just part. This was difficult because I was not familiar with the iguana skeleton. First of all, their clavicles extend all the way around their necks like a collar and they have a second interclavicle below acting like the clavicle in humans. Their sternum, instead of being a single line of bone as in humans, is almost a breastplate covering most of the chest. Some of the muscles that must be removed are attached underneath these bones, so it takes some maneuvering to get them out. 

Friday was an off day. I ended up getting sick and leaving early which means I missed out on almost an entire day of work. So next week I have to catch up and remove the deep muscles of the iguana. There really aren't that many, the problem is identifying them. For example, according to my iguana atlas (Oldham et al, 1975), iguanas have a brachialis muscle, but no brachioradialis. However, this source has been weak in identifying deep muscles. Another source on the forelimb muscles of monitor lizards (a species similar to iguanas), claims that there is only a brachioradialis and not a brachialis (Haines, 1939). However, this brachioradialis inserts and originates at almost the same place as the brachialis of the first source. Then there is the veterinary textbook I've been using (Dyce, 2002) that only references a brachialis muscle. But it uses the forelimb of carnivores for this, and iguana are not carnivores. And then there is the iguana itself. There appears to be only one muscle at the juncture of the elbow between the humerus and radius. There are several possible explanations for this. The first being that all the sources are speaking of the same muscle and have just named them differently. The second is that there are two muscles, but the sources all had different focuses and didn't mention them both. The third would be that there is a conflict in the scientific community about this particular muscle and no one really knows if there is one muscle, two muscles, a fused muscle, or some other variation. Welcome to the academic world.



AA

Dyce, KM, et al. Textbook of Veterinary Anatomy. St. Louis: Saunders, 2002. Print.

Oldham, Jonathan Clark and Hobart Muir Smith. Laboratory Anatomy of the Iguana. Dubuque: WC Brown,   1975. Print.

Haines, R. Wheeler. "A Revision of the Extensor Muscles of the Forearm in Tetrapods." Journal of Anatomy (1939) 73.2: 211-233. Web. 29 Mar 2012.