Limb | Anatomy - Encyclopedia Britannica

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amputation

• In amputation

  …part of or an entire limb, either upper or lower extremity. The reasons for surgical amputation in general are injury, infection, tumour, diabetes, or insufficient blood supply. Persons born without a limb or limbs are said to have suffered congenital amputation. Surgical amputation may be a lifesaving measure for injured…

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development

• In animal development: The appendages: tail and limbs

  …the normal development of the limb. In four-limbed vertebrates (tetrapods), the tips of the limb buds become flattened and broadened into hand or foot plates. The edge of the plate is indented, forming the rudiments of the digits. Meanwhile, local areas of the mesodermal mesenchyme in the interior of the…

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human evolution

• In human evolution: The anatomy of bipedalism

  …orders, the primates have hind-limb-dominated locomotion. Accordingly, human bipedalism is a natural development from the basic arboreal primate body plan, in which the hind limbs are used to move about and sitting upright is common during feeding and rest.

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malformations

• In malformation: Somatic characters

  …of circulation in the developing limb bud of the embryo, followed by necrosis (tissue death) and healing.

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muscle systems

• In muscle: Origins of the tetrapod limbs

  …an increasing emphasis on the limbs for propulsion and by a corresponding de-emphasis on the axial musculature. The limbs of tetrapods are generally similar in overall pattern. Primitively at least, most major groups have similar characteristic features: the fore and hind feet have five digits; there is one bone in…

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• In human muscle system: Evolutionary context

  …by the form of the limb bones and by the preserved footprints of early hominins found from that time.

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proprioception

• In proprioception

  …of the position of each limb. The receptors in the skeletal (striated) muscles and on the surfaces of tendons of vertebrates provide constant information on the positions of limbs and the action of muscles. Comparable organs of arthropods (e.g., insects, crustaceans) include stretch receptors located on the outsides of muscles…

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salamanders

• In amphibian: Embryonic stage

  The development of limbs in the embryos of aquatic salamanders begins in the head region and proceeds in a wave down the body, and digits appear sequentially on both sets of limbs. Salamanders that deposit their eggs in streams produce embryos that develop both sets of limbs before…

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transplants

• In transplant: Transplants and grafts

  …distinguishing feature of organ and limb grafts is that the tissues of the organ or limb can survive only if blood vessels are rapidly joined (anastomosed) to blood vessels of the recipient. This provides the graft with a blood supply before it dies from lack of oxygen and nourishment and…

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