Jälkijäsen

Jälkijäsen is a Finnish term that translates to "hind limb" or "rear limb" in English. It refers to the limbs located at the posterior part of an animal's body. In tetrapods, the four-limbed vertebrates, the hind limbs are typically used for locomotion, propulsion, and balance.

The structure of the hind limb varies significantly across different animal groups, reflecting their evolutionary adaptations and modes of life. For example, in mammals, hind limbs are often adapted for walking, running, jumping, or swimming. Birds possess hind limbs modified for perching, walking, or specialized flight-related movements. Reptiles and amphibians also exhibit diverse hind limb structures, suited for terrestrial, aquatic, or arboreal environments.

In many species, the hind limbs are more powerful and muscular than the forelimbs, as they bear a greater proportion of the animal's weight and are crucial for generating forward momentum. Evolutionary changes in the hind limbs have played a vital role in the diversification of vertebrate life, enabling animals to exploit a wide range of ecological niches. The study of hind limb anatomy and function provides insights into biomechanics, evolutionary history, and the functional morphology of animals.