Katrina Coglitore's Anatomy/Physiology Blog: Chicken Dissection

Trapezius and Latissimus Dorsi

In this lab, we dissected a standard frozen chicken. One thing to keep in mind is that these are meat chickens, bred specifically to be fat in certain places to be nice and plump for human consumption. The goal of this lab was to understand how muscles, tendons, and bones work in collaboration to exhibit movement in the body. Muscles cause movement through contraction and relaxation, and connect to our bones with tendons. While a human and a chicken are very clearly different, there are a lot of similarities to be found, especially in the chicken wing versus the human arm. The two main muscles of the wing are the biceps brachii and the triceps humeralis. When the biceps brachii contracts. the triceps humeralis relaxes, and vice versa. The biceps brachii has its origin site on the humerus. The point of origin remained fixed as an anchor even when we manipulated the rest of the muscle, as we learned previously while we studied muscles. This is just like the human arm, for when our bicep flexes and our triceps relax, our arm bends.

Pectoralis Major and Minor

Also, the trapezius and latissimus dorsi muscles worked similarly in humans. These control the motions of the shoulders. However, there are some differences between humans and chickens. Most notably, there is a difference in the pectoralis muscles. This is what we eat when we eat chicken breast. Yum. These were absolutely humongous on the chicken, and on humans, except for maybe Dwayne "The Rock" Johnson, these are proportional to the rest of our body. The pectoralis major in chickens pulls the wing ventrally and the pectoralis minor pulls the wing dorsally. These functions are different from the human body because we use our arms to do more than just fly.