Somites are blocks of mesoderm that are located on either side of the neural tube in the developing vertebrate embryo. They are essential for segmentation, bone and musculature development, and the formation of the body plan. Somites are formed at specific and consistent intervals unique to each organism, and once formed, various regions within are specified to form only certain cell types, creating a body plan for the organism. The somites give rise to the cells that form the vertebrae and ribs, the dermis of the dorsal skin, the skeletal muscles of the back, and the skeletal muscles of the body wall and limbs. They also contribute to multiple tissues, including the axial skeleton, skeletal and smooth muscles, dorsal dermis, tendons, ligaments, cartilage, and adipose tissue. The total number of somites formed is species-specific and is used as an indicator of embryonic developmental stages.