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Forelimbs in mammals have varying functions but are all homologous. A forelimb or front limb is one of the paired articulated appendages attached on the cranial end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead.
Limbs are attached to the torso via girdles, either the pectoral girdle for the forelimbs, or the pelvic girdle for the hindlimbs.In terrestrial tetrapods, the pectoral girdles are more mobile, floating over the rib cage connected only via the clavicles (to the sternum) and numerous muscles; while the pelvic girdles are typically fused together anteriorly via a fibrocartilaginous joint and ...
Limb formation results from a series of reciprocal tissue interactions between the mesenchyme of the lateral plate mesoderm and the overlying ectodermally derived epithelial cells. Cells from the lateral plate mesoderm and the myotome migrate to the limb field and proliferate to the point that they cause the ectoderm above to bulge out, forming ...
In most terrestrial vertebrates (except snakes, legless lizards and caecillians), the appendicular skeleton and the associated skeletal muscles are the predominant locomotive structures. There are 126 bones in the human appendicular skeleton, includes the skeletal elements within the shoulder and pelvic girdles, upper and lower limbs, and hands ...
Only skeletal and smooth muscles are part of the musculoskeletal system and only the muscles can move the body. Cardiac muscles are found in the heart and are used only to circulate blood; like the smooth muscles, these muscles are not under conscious control. Skeletal muscles are attached to bones and arranged in opposing groups around joints. [8]
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.
Hox genes: [18] Responsible for dictating the anterior-posterior axis of an organism, and is intricately involved in patterning of the developing limb in conjunction with Shh. Influences the activity of TBX and FGF (and possibly Pitx1) proteins. Determines where limb buds will form, and what limbs will develop there.
The origin of a muscle is the bone, typically proximal, which has greater mass and is more stable during a contraction than a muscle's insertion. [14] For example, with the latissimus dorsi muscle, the origin site is the torso, and the insertion is the arm. When this muscle contracts, normally the arm moves due to having less mass than the torso.