Clinical genetics / edited by Arnold Sorsby.

Date:
1953
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Clinical genetics / edited by Arnold Sorsby. Source: Wellcome Collection.

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    THE PELVIS ischaemic necrosis occurring in other parts of the skeleton, such as Perthes' disease and Osgood-Schlatter's disease. Persistence of infantile type of pelvis.—Persistence of the infantile type of pelvis may be associated with unilateral hypoplasia of one of the wings of the sacrum and presents an obhquely contracted pelvis. A rare, transversely contracted pelvis may result from under-development of both wings of the sacrum. These and other pelvic anomalies may be associated with developmental anomalies of the vertebral column. Open pubic arch.—The pubic arch may be open and the bodies of the pubic bones may be spread apart in exstrophy of the bladder. Deep acetabulum and intrapelvic protrusion.—In this condition the inner ace¬ tabular wall protrudes into the pelvis, the acetabular cavity is usually enlarged, especially inward and upward. The head of the femur—essentially of normal contour—is displaced into the deepened acetabulum. The lower extremity is usually shortened. The condition is usually bilateral and commoner in women. Congenital luxation and dislocation of hip.—Hypoplasia of the rim of the ace¬ tabulum and a small, shallow acetabular cavity associated with congenital anomalies of the hip is probably the most important anomaly of this region. Many theories have been evolved to explain the aberrations of the hip joint (Badgley; Hart, 1942), and all assume a hereditary factor. The primary gene variation theory implies a localized aplasia (germinal aplasia) from which the different forms and degrees of the deformity develop. Preluxation, subluxation and dislocation merely represent degrees of the aplasia. Mechanical factors are secondary (Badgley). In the majority of cases subluxation exists at birth and may or may not develop into dislocation. A sex influence favouring females is present. Generalized skeletal dystrophies.—The following general skeletal dystrophies, discussed elsewhere, may effect pelvic aberrations : (1) osteogenesis imperfecta; (2) chondrodystrophy; (3) diaphyseal aclasis; (4) osteopetrosis; (5) cleido¬ cranial dysostosis; (6) reticuloses; and (7) thalasseamia. Heredity There are few genetic studies of these anomalies. Accessory secondary ossification centres.—Twin studies have revealed that the accessory ossification centres are genetically determined, but as yet nothing is known about the hereditary mechanism. Ischiopubic osteochondrosis.—Twin studies and the occasional association of ischiopubic osteochondrosis with other forms of osteochondritis in the same individual suggest that genetic factors may play a significant role. Persistence of infantile type of pelvis.—Genetic factors are instrumental, but the hereditary mechanism is not known. Open pubic arch.—This disorder is most frequently associated with other genetically determined anomalies of the spinal division of the central nervous system such as spina bifida manifesta and meningoceles. Deep acetabulum and intrapelvic protrusion.—Three of Rechtman's cases (1936) suggested a hereditary background. In 1 family 7 individuals were believed affected in 2 generations. In a second family 6 affected individuals appeared in 3 generations. The trait appears to be due to a dominant gene. 267