Muscles of the Arm and Forearm

10/28/14-10/30/14

Procedure:

1. Place the cat on its back then take the upper arm and identify the superficial muscles. You should be looking at the inner-side of the cat’s upper arm. The following superficial muscles should be identified: the spinodeltoid (previously identified), the brachialis, the acromiodeltoid (previously identified), the triceps (the long head) and triceps brachii (the medial head and previously identified). The acromiodeltoid is superior (above) to the brachialis. The spinodeltoid is inferior (below) to the brachialis. The brachialis is intermediate between the acromiodeltoid and the spinodeltoid. To the right of these three muscles are the triceps brachii and the triceps. The triceps brachii are superior (above) to the triceps. Review the Anatomy booklet for further direction on the location of these superficial muscles.
2. With a scalpel, clearly outline the superficial muscles of the upper arm and then take a picture.
3. Identify the superficial muscles of the forearm. You should be looking at the inner-side of the cat’s forearm. The following superficial muscles should be identified: the brachioradialis, the extensor carpi radialis longus, the extensor digitorum communis, the extensor digitorum lateralis and the extensor carpi ulnaris. Image the cat’s forearm in the anatomical position. The extensor carpi ulnaris would be closest to the midline and the brachioradialis would be farthest lateral (away) from the midline. From left to right is the extensor carpi ulnaris (farthest left), then the extensor digitorum lateralis, then the extensor digitorum communis, then the extensor carpi radialis longus and lastly the brachioradialis (farthest right). Review the Anatomy booklet for further direction on the location of these superficial muscles.
4. With a scalpel, make an incision on each of the striations, which separate these muscles. These incisions will clearly outline the superficial muscles of the forearm. When finished take a picture.
5. Next, begin to identify the deep muscles of the arm and forearm. The following deep muscles should be identified: the extensor carpi radialis brevis, the flexor carpi radialis, the palmaris longus, the flexor carpi ulnaris, the pronator teres, and the epitrochlearis. The extensor carpi radialis brevis is the deep muscle directly underneath the extensor carpi radialis longus, which is proximal to the brachioradialis (previously identified). The pronator teres is a small muscle intermediate between the extensor carpi radialis brevis (right of pronator teres) and the flexor carpi radialis (left of the pronator teres). The pronator is also superior (above) the epitrochlearis, which is a bigger muscle underneath the triceps (previously identified). The palmaris longus is intermediate between the flexor carpi radialis (right of palmaris longus) and the flexor carpi ulnaris (left of palmaris longus). These three muscles are all superior (above) the epitrochlearis. Review the Anatomy booklet for further direction on the location of these superficial muscles.
6. With a scalpel, carefully make incisions (or cut off superficial muscle if needed) to identify the deep arm and forearm muscles described above. Take a picture.
7. Locate and identify the biceps brachii, which is intermediate between the clavobrachialis and the pectoantebrachialis. The clavobrachialis being superior (above) the biceps brachii and the pectoantebrachialis being inferior (below) the biceps brachii. Take a picture of this muscle.
8. Be aware of how the superficial chest muscles meet the superficial and deep arm and forearm muscles. Observe where these muscles meet then take a picture.

Materials: scalpel

Data and Observations:

All of Semara’s superficial and deep arm and forearm muscles were in great condition and in the correct place. The superficial arm muscles were able to be clearly identified as well as the deep arm muscles. The striations on Semara’s forearm helped to identify the superficial muscles. Semara’s superficial muscles were fairly thin as well as Semara’s deep forearm muscles. Semara’s superficial and deep muscles on her upper arm were definitely thicker and healthier. Pictures of the data collected are shown below.

Human Corresponding Arm and Forearm Muscles

(also shows part of the human shoulder muscles)

Conclusion:

Identifying the outlining Semara’s superficial muscles on her upper arm was quite easy. Doing the same for her superficial forearm muscles was easy as well. Identify Semara’s deep arm muscles was also easy but, identify her deep forearm muscles was more difficult because they were very small, thin muscles located directly underneath the superficial forearm muscles, which were also small and thin. I did enjoy observing how the superficial muscles of the chest connect to the muscles of the arm and forearm. Having the opportunity to observe all the muscle connecting to each other really gave me a better understanding of the anatomy. Also, Labeling my pictures and diagrams helped me understand where the muscles of the arm and forearm are located and which muscles they are connected too. I definitely enjoyed working on the arm and forearm muscles a lot better than the back and shoulder.