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Limb development. Development of the limbs. Illustration of a human embryo at six weeks gestational age. 9-week human fetus from ectopic pregnancy. Anatomical terminology. [ edit on Wikidata] Limb development in vertebrates is an area of active research in both developmental and evolutionary biology, with much of the latter work focused on the ...
Limb (anatomy) A limb (from Old English lim, meaning "body part") is a jointed, muscled appendage of a tetrapod vertebrate animal used for weight-bearing, terrestrial locomotion and physical interaction with other objects. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular ...
The limb bud is a structure formed early in vertebrate limb development. As a result of interactions between the ectoderm and underlying mesoderm, formation occurs roughly around the fourth week of development. [1] In the development of the human embryo the upper limb bud appears in the third week and the lower limb bud appears four days later. [2]
Recently, there have been comparative studies of mouse and bat forelimb development to understand the genetic basis of morphological evolution. Consequently, the bat wing is a valuable evo-devo model for studying the evolution of vertebrate limb diversity. diagram showing homologous skeletal structures of bat and mouse
Multiple features differentiate the embryologic development of snakes from other vertebrates, two significant factors being the elongation of the body and the lack of limb development. Diagram illustrating differential somite size due to difference in somitogenesis clock oscillation [ 95 ]
Anatomical terminology. [edit on Wikidata] The zone of polarizing activity (ZPA) is an area of mesenchyme that contains signals which instruct the developing limb bud to form along the anterior/posterior axis. Limb bud is undifferentiated mesenchyme enclosed by an ectoderm covering. Eventually, the limb bud develops into bones, tendons, muscles ...
The femur (/ ˈfiːmər /; pl.: femurs or femora / ˈfɛmərə /), [1][2] or thigh bone, is the only bone in the thigh — the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg. The top of the femur fits into a socket in the pelvis called the hip joint, and the bottom ...
Body schema is an organism's internal model of its own body, including the position of its limbs. The neurologist Sir Henry Head originally defined it as a postural model of the body that actively organizes and modifies 'the impressions produced by incoming sensory impulses in such a way that the final sensation of body position, or of locality, rises into consciousness charged with a relation ...