Anatomy of Chest Muscles in Land and Marine Animals

• The chest is made up of two main parts: the upper, triangular, and lower, mesh-like parts. In the process of evolution, the chest muscles of land animals split into a upper, triangular part and a lower, mesh-like part. The upper, triangular part becomes the upper arm bone in land animals, and the lower, mesh-like part becomes the lower arm bone. The mesh-like part in land animals also becomes the chest muscle in marine animals. The chest muscles of land animals and marine animals are innervated by a triune nerve.

• The chest muscles in land animals and marine animals are used to perform different functions. The upper, triangular part of the chest muscle in land animals is used to raise the arm, and the lower, mesh-like part is used to support the arm. The mesh-like part in marine animals is used to support the body, and the upper, triangular part is used to catch prey.

• The chest muscles in land animals and marine animals are composed of three parts: the upper, triangular part, the lower, mesh-like part, and the muscle fibers. The muscle fibers in the chest muscles in land animals and marine animals are arranged in a triple layer. The upper, triangular part and the lower, mesh-like part are the primary parts, and the muscle fibers in the mesh-like part are arranged in a triple layer. The upper, triangular part and the lower, mesh-like part form the chest muscle, and the muscle fibers in the mesh-like part form the chest muscle fibers. The muscle fibers in the mesh-like part in marine animals are arranged in a triple layer, and the muscle fibers in the mesh-like part in marine animals are arranged in a quadruple layer. The muscle fibers in the mesh-like part in marine animals are used to support the body, and the muscle fibers in the upper, triangular part are used to raise the arm.

• The chest muscles in land animals and marine animals are innervated by a triune nerve. The triune nerve is composed of three parts: the upper, middle, and lower parts. The upper, middle, and lower parts are responsible for different functions. The upper part of the triune nerve is responsible for the muscle fibers in the upper, triangular part and the lower, mesh-like part, and the middle part of the triune nerve is responsible for the muscle fibers in the mesh-like part. The lower part of the triune nerve is responsible for the muscle fibers in the lower, mesh-like part and the muscle fibers in the upper, triangular part.

Explore the unique composition and functions of chest muscles in land animals and marine animals, including the distinct roles of the upper, triangular part and lower, mesh-like part. Delve into the innervation by the triune nerve and the arrangement of muscle fibers, uncovering the evolutionary and functional adaptations in these diverse species.