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A hindlimb or back limb is one of the paired articulated appendages attached on the caudal end of a terrestrial tetrapod vertebrate's torso. [1] With reference to quadrupeds, the term hindleg or back leg is often used instead. In bipedal animals with an upright posture (e.g. humans and some primates), the term lower limb is often used.
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. These differences can be treated schematically by considering how they are reflected in each of the limb's three main axes.
Skeletons of a human and an elephant. Comparative foot morphology involves comparing the form of distal limb structures of a variety of terrestrial vertebrates.Understanding the role that the foot plays for each type of organism must take account of the differences in body type, foot shape, arrangement of structures, loading conditions and other variables.
In the polyphyletic hypothesis (PH), frogs and salamanders evolved from dissorophoid temnospondyls while caecilians come out of microsaur lepospondyls, making both lepospondyls and temnospondyls true tetrapods.
In chickens, Tbx4 specifies hindlimb status, while Tbx5 specifies forelimb status. [13] 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 ...
The frog is a part of a horse hoof, located on the underside, which should touch the ground if the horse is standing on soft footing. The frog is triangular in shape, and extends midway from the heels toward the toe, covering around 25% of the bottom of the hoof.
It is used by scientists to obtain a better understanding of biological function through the study of cellular dynamics. [1] Live-cell imaging was pioneered in the first decade of the 21st century. One of the first time-lapse microcinematographic films of cells ever made was made by Julius Ries, showing the fertilization and development of the ...
The marsupial frogs are a disputed family (Amphignathodontidae) in the order Anura. [1] When treated as a separate family, it consists of two genera, Gastrotheca and Flectonotus. [2] The frogs are native to Neotropical America (Central and South America). Under the dominant view, they are treated as part of the family of Hemiphractidae. [1] [3] [4]