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The patella (pl.: patellae or patellas), also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint.
Animals have been selected so that each number from 0 to 55 leg pairs has one example listed. Each of these examples is listed by a number closely associated with the relevant taxon, either because that number is the one most commonly observed in that taxon or because it is one of only a few numbers recorded for the taxon.
In terrestrial animals, plantigrade locomotion means walking with the toes and metatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrial mammals . The other options are digitigrade , walking on the toes and fingers with the heel and wrist permanently raised, and unguligrade , walking on the nail or nails of ...
Digitigrade and unguligrade animals have relatively long carpals and tarsals, and the bones which correspond to the human ankle are thus set much higher in the limb than in a human. In a digitigrade animal, this effectively lengthens the foot, so much so that what are often thought of as a digitigrade animal's "hands" and "feet" correspond to ...
Most birds have four toes, typically three facing forward and one pointing backward. [7] [10] [8] In a typical perching bird, they consist respectively of 3, 4, 5 and 2 phalanges. [2] Some birds, like the sanderling, have only the forward-facing toes; these are called tridactyl feet while the ostrich have only two toes (didactyl feet).
The nail is an unguis, meaning a keratin structure at the end of a digit. Other examples of ungues include the claw, hoof, and talon. The nails of primates and the hooves of running mammals evolved from the claws of earlier animals. [38] In contrast to nails, claws are typically curved ventrally (downwards in animals) and compressed sideways.
The foot (pl.: feet) is an anatomical structure found in many vertebrates.It is the terminal portion of a limb which bears weight and allows locomotion.In many animals with feet, the foot is a separate [clarification needed] organ at the terminal part of the leg made up of one or more segments or bones, generally including claws and/or nails.
Most species use their nails to dig seeds out of mud or vegetation, [62] while diving ducks use theirs to pry molluscs from rocks. [63] There is evidence that the nail may help a bird to grasp objects. Species which use strong grasping motions to secure their food (such as when catching and holding onto a large squirming frog) have very wide ...