Synostosis
Synostosis is fusion of two bones. It can be normal in puberty, fusion of the epiphyseal plate to become the epiphyseal line, or abnormal. When synostosis is abnormal it is a type of dysostosis.
Examples of synostoses include:
Synostosis within joints can cause ankylosis.Clinical significance
is one of the more common failures of separation of parts of the upper limb. There are two general types: one is characterized by fusion of the radius and ulna at their proximal borders and the other is fused distal to the proximal radial epiphysis. Most cases are sporadic, congenital and less often post-traumatic, bilateral in 60%, and more common in males. Familial cases in association with autosomal dominant transmission appear to be concentrated in certain geographic regions, such as Sicily.
The condition frequently is not noted until late childhood, as function may be normal, especially in unilateral cases. Increased wrist motion may compensate for the absent forearm motion. It has been suggested that individuals whose forearms are fixed in greater amounts of pronation face more problems with function than those with around 20 degrees of fixation. Pain is generally not a problem, unless radial head dislocation should occur.
Most examples of radioulnar synostosis are isolated. Syndromes that may be accompanied by radioulnar synostosis include X chromosome polyploidy and other chromosome disorders, acrofacial dysostosis, Antley–Bixler syndrome, genitopatellar syndrome, Greig cephalopolysyndactyly syndrome, hereditary multiple osteochondromas, limb-body wall complex, and Nievergelt syndrome.
Craniosynostosis is a condition in which one or more of the fibrous sutures in an infant skull prematurely fuses by turning into bone. Craniosynostosis has following kinds: scaphocephaly, trigonocephaly, plagiocephaly, anterior plagiocephaly, posterior plagiocephaly, brachycephaly, oxycephaly, pansynostosis.
