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The locomotion of the elephant (which is the largest terrestrial vertebrate) displays a similar loading distribution on its hind limbs and forelimbs. [10] The walking and running gaits of quadrupeds and bipeds show differences in the relative phase of the movements of their forelimbs and hind limbs, as well as of their right-side limbs versus ...
The cranial pair (i.e. closer to the head) of limbs are known as the forelimbs or front legs, and the caudal pair (i.e. closer to the tail or coccyx) are the hindlimbs or back legs. In animals with a more erect bipedal posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs ...
All vertebrate forelimbs are homologous, meaning that they all evolved from the same structures. For example, the flipper of a turtle or of a dolphin, the arm of a human, the foreleg of a horse, and the wings of both bats and birds are ultimately homologous, despite the large differences between them. [1]
The development of the basic limb plan is accompanied by the generation of local differences between the elements. For example, the radius and ulna of the forelimb, and the tibia and fibula of the hindlimb of the zeugopod are distinct from one another, as are the different fingers or toes in the autopod.
In mice, however, both hindlimbs and forelimbs can develop in the presence of either Tbx4 or Tbx5. [14] In fact, it is the Pitx1 and Pitx2 genes that appears to be necessary for specification of the developing hindlimb, whereas their absence results in forelimb development. [15] Tbx4 and Tbx5 appear to be important specifically for limb ...
One of these changes is having longer hindlimbs proportional to the forelimbs and their effects. As previously mentioned, longer hindlimbs assist in thermoregulation by reducing the total surface area exposed to direct sunlight while simultaneously allowing for more space for cooling winds. Additionally, having longer limbs is more energy ...
The intermembral index is a ratio used to compare limb proportions, expressed as a percentage. [1] It is equal to the length of forelimbs (humerus plus radius) divided by the length of the hind limbs (femur plus tibia) multiplied by 100, [2] otherwise written mathematically as:
Having long hind limbs and short forelimbs allows humans to walk upright, while orangutans and gibbons had the adaptation of longer arms to swing on branches. [12] Apes can stand on their hindlimbs, but they cannot do so for long periods of time without getting tired. This is because their femurs are not adapted for bipedalism.