Functional Anatomy of the Thoracic Limb of the Komodo Dragon (Varanus komodoensis)

SIMPLE SUMMARY: The Komodo dragon’s conservation and acquisition of detailed biological knowledge are considered contemporary priorities. The geographical location and behavior of this animal make research in the wild difficult. Varanus komodoensis is gigantic, endemic, and relict—a link between ancestors and modern monitor lizards. The anatomical adaptations of the biological functions made by the movement system in the thoracic limb have not been well documented yet. During dissection, the predominance of the saddle joints over the ball joints and the extensive antigravity functions of the biceps and triceps muscle groups were confirmed. Furthermore, a greater differentiation of the forearm muscles in relation to the pelvic limb musculature was also observed. These analogies may indicate adaptation for enhanced manual dexterity and orientation skills in the animal’s natural habitat, characterized by a robust and well-preserved physique. The muscles ensuring the rotation of the ulna relative to the humerus are also well developed, giving the animal a possibility to rest in physiological support, transferring the center of gravity towards the head, thus indicating functions and determining locomotive abilities. The anatomical description has many cognitive values—in both veterinary orthopedics and maintenance in zoos, biodiversity conservation, and reconstructing archaeological data about extinct animals. ABSTRACT: Since the Komodo dragon has been included on The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, it is crucial to know in detail its biology as there is a limited availability of research material on these animals—mainly those who died in zoos or whose remains were found in the wild. Anatomy is essential for understanding physiology, identification of diseases, adaptations in the environment, and behavior. In this dissection study, the relationship of individual anatomical structures was analyzed, the anatomy of the active and passive movement system of the thoracic limb was described, photographs were taken, and a radiographic examination was conducted. This species has its own differences, even within closely related lizard species. Varanus komodoensis possesses triceps muscles with three heads, and the wrist is extended with additional bones for greater flexibility of the hand. The muscles of the forelimb are analogous to the hind limb; however, they differ in the mass of individual muscles, especially those predisposed to perform the most important antigravity and locomotive functions.