Long bone length is stimulated by the production of growth hormone (GH), a secretion of the anterior lobe of the pituitary gland. The long bone includes the femora, tibiae, and fibulae of the legs; the humeri, radii, and ulnae of the arms; metacarpals and metatarsals of the hands and feet, the phalanges of the fingers and toes, and the clavicles or collar bones. The long bones of the human leg comprise nearly half of adult height. The other primary skeletal component of height are the vertebrae and skull. The outside of the bone consists of a layer of connective tissue called the
Vancleavea parts of the hand. The second metacarpal is longer, and the third and fourth are tied for the longest bones of the hand. Unguals (claws) have not been found, and the rounded ends of certain phalanges indicates that "Vancleavea" likely did not possess them. As with other reptiles, each hip of "Vancleavea" is formed by three plate-like bones: the illium (above the hip socket), the pubis (in front of the hip socket), and the ischium (behind the hip socket). The illium of "Vancleavea" is particularly unusual. Most archosauriforms have illia which are somewhat low, directed from front to back (anteroposteriorly).