Chicken Dissection Analysis

In this lab, we dissected an entire chicken. The first thing we did was pat it dry and remove all the skin from the breast part, and then we identified the various muscles, even cutting off a wing to take a look close up at the muscles in the "arm" of the chicken. The bones provide the structural frame of the chicken, and the tendons attach to the bones and muscles to keep everything stable. The muscles are responsible for controlling the movement of the chicken and supporting is structure. For example, when we flexed and extended the leg of our chicken, we could clearly feel the quadriceps tensing and relaxing, so we knew that it was responsible for that movement.

One major difference between the tendon where it attaches to the origin and insertion site is that at the site of insertion, all the tendon fibers are bundled together very tightly and compactly, whereas at the origin, it fans out a bit and becomes a thinner layer of visible tendon fibers where it attaches. At the site of insertion, there must be a very strong foundation, so the tendon is very compact to ensure that it can hold all the weight. The site of origin requires the tendon to support the bone, so it is required to be more spread out in order for nerve impulses and motion neurons to reach it more easily.
The chicken has much larger pectoralis major that humans do, which is because chickens are farmed for food, and humans prefer chicken breast, so they select the chickens to breed so that all the offspring have larger pectoralis major. Compared to humans, chickens have a relatively small trapezius muscle, probably because they have such a small head and stubby neck, so they don't need that much muscles to hold their head up. Compared to chickens, we have very large and heavy heads with a relatively long neck, so we need stronger trapezius muscles to support our head movements. Finally, chickens also have a very large tibialis major, which is located on their leg, the drumstick part. This is also because humans really like to eat drumsticks, so chickens are bred to have large drumsticks. At the same scale, humans have much smaller tibialis major. Below are the pictures that we took of the muscles and other parts:

Deltoid allows arm abduction along frontal plane.

Trapezius muscle moves scapula and supports arm movements. 

Latissimus Dorsi allows for extension, flexion, rotation of shoulder joint, and more.

Pectoralis minor abducts and depresses the scapula toward the ribs. 

Pectoralis major moves the shoulder joint.

Biceps Brachii controls the movement between the shoulder and elbow joints.

Triceps Humeralis are supportive of arm structure and have populations of slow fibers. 

The flexor carpi ulnaris adducts and flexes the hand.

Biceps femoris supports the knee extension.

brachioradialis flexes forearm at elbow. 

Quadriceps extend the knee joint and are used for walking and running.

semimembranosus allows leg to flex and rotate and serves as a thigh extensor. 

Tendons are dense collagenous fibers that connect muscles to bones. 

Semitendinosus works with other hamstring muscles to flex knee and extend hip.

Iliotibialis flexes the thigh. 

The longest muscle in the body, the sartorius flexes, adducts and rotates the hip. 

Gastrocnemius flexes the knee and foot. 

Peronius Longus everts and pronates the foot. 

The tibialis anterior dorsiflexes and inverts the foot.