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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    skull П. Regional affections of the skeletal system SKULL Minor variations of the skull contour are particularly common and many may have demonstrable genetic background. The Hapsburg lip (prognathism) and Catlin mark may serve as examples. Specific familial physiognomy is well known and within the intimate experience of all. Some skull anomalies are marked and are of pathological significance. Clinical aspects Congenital dysplasias of the skull Meningocele, meningo-encephalocele, and cranium bifidum occultum are of infrequent occurrence, but when present they are median plane defects usually located in the vicinity of the occipital and accessory fontanelles. These defects frequently may be associated with spina bifida of the upper cervical spine. Mental defects of varying grades of severity exist. Many other associated developmental anomalies of the skeletal system are encountered. Lacunar skull of the newborn In the lacunar skull of the newborn irregular circular or oval thickenings appear on the inner surface of the skull with a corresponding thinning. A multiple soap- bubble appearance is observed roentgenologically. The defect is always associated with abnormalities of the central nervous system—spina bifida of the thoracic region—and is attributed to foetal increased intracranial pressure. Enlarged parietal foramina Enlarged parietal foramina may appear as varying sized defects of the posterior angles of the parietal bones. These defects apparently arise from a failure of mineralization of the membranous bones of the skull. Approximately 10 per cent of the skulls present small defects in this region. They are not associated with other skeletal defects. The sex incidence appears to be equal. The question of the relationship of the defect to the parietal foramen is still controversial. Congenital craniostenoses The craniostenoses represent a group of malformations of the skull effected by premature synostoses of two or more of the cranial bones associated with obliteration of the involved sutures. A defective development of the mesenchymal capsule of the skull, of unknown aetiology, is thought responsible and is frequently associated with other congenital anomalies. A localized expansion of the growing skull is prevented or limited in a direction perpendicular to the long axis of the obliterated suture. This results in a compensatory overgrowth of the skull in other directions. It is becoming increasingly evident that the craniostenoses may be associated with generalized bone marrow disorders such as congenital haemolytic anaemia and pernicious anaemia. Oxycephaly.—The most striking feature in oxycephaly (tower skull) is the great height of the skull. Exophthalmos and defects of muscle balance are commonly associated as is secondary optic atrophy. Males are more frequently affected. 259