DEVELOPMENT OF THE MUSCULOSKELETAL SYSTEM

DEVELOPMENT OF THE MUSCULOSKELETAL SYSTEM

The upper limb bud forms on the lateral wall of the 4-week embryo, followed promptly by the lower limb bud. By 2 /uni00A0 months, di ff erentiation of the limb elements is complete. Most congenital limb anomalies arise during this period. Three coordinated signalling centres control limb devel opment. The apical ectodermal ridge (AER) guides Carl Hueter , 1838–1882, Professor of Surgery , University of Greifswald, Germany . Richard von Volkmann , 1830–1889, Professor of Surgery , Halle, Germany . Julius Wol ff , 1836–1902, Professor of Orthopaedic Surgery , Berlin, Germany . mesodermal di ff erentiation in a proximal-to-distal direction, controlling digit formation via the production of fibroblast growth factors (FGFs). The mesodermal zone of polaris - ing activity (ZPA) directs anteroposterior development via the sonic hedgehog protein, which is itself sustained by FGFs. The ectodermal driven wingless-type (Wnt) signalling centre develops dorsoventral axis configuration and limb alignment. Certain limb anomalies are directly related to alterations in these centres. Experimentally , removal of the AER leads to a truncated limb, similar to a congenital amputation, and pre - vents interdigital necrosis resulting in syndactyly . An additional ZP A results in a mirror duplication of the distal limb. Factors causing fetal limb anomalies may also influence other organ formation, resulting in potentially life-threa tening disorders. Summary box 44.1 Development of the musculoskeletal system /uni25CF /uni25CF /uni25CF /uni25CF

Presentation and management of other childhood hip • conditions Management of club foot • Problems associated with musculoskeletal infection in • childhood Occurs 4–8 weeks after fertilisation AER controls proximal-to-distal differentiation and interdigital necrosis ZPA directs posterior-to-anterior differentiation Wnt in /f_l uences dorsal-to-ventral differentiation

DEVELOPMENT OF THE MUSCULOSKELETAL SYSTEM

The upper limb bud forms on the lateral wall of the 4-week embryo, followed promptly by the lower limb bud. By 2 /uni00A0 months, di ff erentiation of the limb elements is complete. Most congenital limb anomalies arise during this period. Three coordinated signalling centres control limb devel opment. The apical ectodermal ridge (AER) guides Carl Hueter , 1838–1882, Professor of Surgery , University of Greifswald, Germany . Richard von Volkmann , 1830–1889, Professor of Surgery , Halle, Germany . Julius Wol ff , 1836–1902, Professor of Orthopaedic Surgery , Berlin, Germany . mesodermal di ff erentiation in a proximal-to-distal direction, controlling digit formation via the production of fibroblast growth factors (FGFs). The mesodermal zone of polaris - ing activity (ZPA) directs anteroposterior development via the sonic hedgehog protein, which is itself sustained by FGFs. The ectodermal driven wingless-type (Wnt) signalling centre develops dorsoventral axis configuration and limb alignment. Certain limb anomalies are directly related to alterations in these centres. Experimentally , removal of the AER leads to a truncated limb, similar to a congenital amputation, and pre - vents interdigital necrosis resulting in syndactyly . An additional ZP A results in a mirror duplication of the distal limb. Factors causing fetal limb anomalies may also influence other organ formation, resulting in potentially life-threa tening disorders. Summary box 44.1 Development of the musculoskeletal system /uni25CF /uni25CF /uni25CF /uni25CF

Presentation and management of other childhood hip • conditions Management of club foot • Problems associated with musculoskeletal infection in • childhood Occurs 4–8 weeks after fertilisation AER controls proximal-to-distal differentiation and interdigital necrosis ZPA directs posterior-to-anterior differentiation Wnt in /f_l uences dorsal-to-ventral differentiation

DEVELOPMENT OF THE MUSCULOSKELETAL SYSTEM

The upper limb bud forms on the lateral wall of the 4-week embryo, followed promptly by the lower limb bud. By 2 /uni00A0 months, di ff erentiation of the limb elements is complete. Most congenital limb anomalies arise during this period. Three coordinated signalling centres control limb devel opment. The apical ectodermal ridge (AER) guides Carl Hueter , 1838–1882, Professor of Surgery , University of Greifswald, Germany . Richard von Volkmann , 1830–1889, Professor of Surgery , Halle, Germany . Julius Wol ff , 1836–1902, Professor of Orthopaedic Surgery , Berlin, Germany . mesodermal di ff erentiation in a proximal-to-distal direction, controlling digit formation via the production of fibroblast growth factors (FGFs). The mesodermal zone of polaris - ing activity (ZPA) directs anteroposterior development via the sonic hedgehog protein, which is itself sustained by FGFs. The ectodermal driven wingless-type (Wnt) signalling centre develops dorsoventral axis configuration and limb alignment. Certain limb anomalies are directly related to alterations in these centres. Experimentally , removal of the AER leads to a truncated limb, similar to a congenital amputation, and pre - vents interdigital necrosis resulting in syndactyly . An additional ZP A results in a mirror duplication of the distal limb. Factors causing fetal limb anomalies may also influence other organ formation, resulting in potentially life-threa tening disorders. Summary box 44.1 Development of the musculoskeletal system /uni25CF /uni25CF /uni25CF /uni25CF

Presentation and management of other childhood hip • conditions Management of club foot • Problems associated with musculoskeletal infection in • childhood Occurs 4–8 weeks after fertilisation AER controls proximal-to-distal differentiation and interdigital necrosis ZPA directs posterior-to-anterior differentiation Wnt in /f_l uences dorsal-to-ventral differentiation