![]() During the 9th week, all digits are formed, heads of the first and fifth metatarsals drop downward, and the transverse arch of the foot form. During the 8th week, the forefoot is adducted, and notches between the toes are visible. ĭuring 6th week, the paddle-shaped foot lies inverted and equinus in position. As per the position, digits are given numbers. Autopodium forms a digital plate demarcated into digital rays, which form digits, and interdigital tissue between digital rays disintegrates by apoptosis. Mesopodium considers a segment between autopodium and zeugopodium, giving rise to tarsals. The Human pentadactylous hind limb has been differentiated into three segments.Īutopodium gives rise to skeletal elements of the foot (metatarsals and phalanges). In some tarsal bones, endochondral ossification starts after birth. Ossification of cartilaginous models begins at the 10th week, which may continue after birth till puberty to complete the secondary ossification process. Īround the 6th week cartilaginous skeleton forms by chondrification. Limb development may be hampered if AER is affected or removed. ![]() AER has a role in the development of skeletal elements by releasing various signals. Mesenchyme will condense to form ligaments and the skeleton of the hindlimb, While ectoderm forms the skin and its appendages. įollowing interactions between epithelium and mesenchyme, an apical ectodermal ridge (AER) is formed from ectoderm. The limb bud grows from the proximal to the distal, and a primitive footplate is formed at 4.5 weeks. ![]() The hind limb bud develops as bulging on the ventrolateral surface in the 4th week of the embryo by the proliferation of the somatopleuric layer of lateral plate mesoderm opposite to 元 to L5 somites covered by ectoderm. Foot has to suffer from many deformities due to either congenital anomalies or acquired injury by improper shoewear or high heels. An arched foot has the capability of shock absorption and adaptation to uneven surfaces. These arches of the foot provide a flexible platform to support body weight, and it also acts as a multisegmented lever for propulsion in walking, running, and jumping. It is present since birth but is masked by the presence of the fat pad in children. These arches make the sole concave so that our footprint is incomplete. These arches are formed by the shapes of tarsals and metatarsals and are supported by ligaments and extrinsic and intrinsic muscles of the foot. Among the longitudinal arches, the medial arch has more height, while among the transverse arches, the anterior arch is complete, while the posterior arch is half dome-shaped and incomplete. The human foot has two longitudinal (medial and lateral) and two transverse arches (anterior and posterior transverse arches). Arches of the foot helps in providing upright posture and weight bearing. An arched foot is characteristic of humans, distinguishing it from other primates.
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