Chicken Dissection Lab Analysis

In this lab, I dissected a chicken (pre-plucked, with no head or feet) to become more familiar with the different muscles and how movements correspond with muscles. For example, we would pull on the wing to see different muscles move as those would be the muscles that normally contract to cause that action such as pulling the wing up to exercise the pectoralis major which is responsible for flight in birds. In addition, the biceps brachii works to bend the wing in chickens, and is connected to the humerus. The origin is proximal to the body; for example, with the latissimus dorsi, it is attached to the arm. The insertion is where the muscle is attached to the bone or tendon and is distal to the body. In chicken muscles, the pectoralis major are much larger than those of humans since chickens must use those breast muscles to fly. Another comparison between chicken muscles and human muscles can be seen in their function such as with the triceps humeralis where in chickens it straightens the wing and in humans it is used for reverse curls. The flexor carpi ulnaris is a connected to a chicken's thumb and flexes it while in humans, the hand can be flexed using all five fingers.

The pectoralis major is the breast muscle of the bird and pulls the wing up, powering flight in chickens.

The pectoralis minor lifts the wing dorsally and pulls the shoulder down and forward.

The trapezius helps to shrug the shoulders, running perpendicular from the backbone to the shoulder.

The latissimus dorsus runs from the spine into the arm pit/wing, extending the wing/arm.

The deltoid raises the upper arm/wing and is on the center top of the shoulder. 

The triceps humeralis straightens the wing/arm. The biceps brachii flexes/bends the wing/arm.

The brachioradialis pulls the hand back and the flexor carpi ulnaris flexes the hand.

The gastrocnemius is attached to the achilles tendon and extends the foot and flexes the lower leg. The Peroneus longus extends the foot. The tibialis anterior flexes the foot.

The sartorius flexes the thigh and allows crossing of the legs. The iliotibialis or tensor fasciae latae, gluteus maximus and iliotibial tract extends the thigh and flexes the leg.

The biceps femoris flexes the leg and helps make up the hamstring group. The quadriceps femoris or vastus lateralis, intermedius and medialis and rectus femoris flexes the thigh and extends the lower leg. This is also known as the quadricep.

The semimembranousus extends the thigh and the semitendinosus extends the thigh as well but is anterior and medial to the semimembranosus.