Multiple ossification centres in the epiphyses of the long bones of the human hand and foot.

The extensive literature dealing with radiographic changes in bones during normal development is concerned principally with the time at which epiphysial centres appear and the ages at which they fuse with the diaphyses. Little attention has been paid to the appearance and form of these epiphyses soon after they have become radio-opaque. This paper directs attention to the frequent occurrence of multiple ossification centres in many epiphyses of the hand and foot. REVIEW OF THE LITERATURE Observations on the number of centres of ossification in an epiphysis-Serres (1829, 1838) saw two and three epiphysial centres for the thumb and big toe in parts that had been dissected, and Rambaud and Renault (1864) also discovered two centres of ossification in certain phalanges and in a metatarsal bone. With the advent of radiology there have been many observations on the first appearance of epiphyses in general. Some authors, such as Pryor (1925), believe that the ossification centre starts as a pin-point of bone tissue which “ gradually enlarges and approaches the form of the bone.” Others believe that individual centres of ossification may appear as multiple bony nodules (Greulich and Pyle 1950; Caffey 1956; Shanks, Kerley and Twining 1939; Pyle and Hoerr 1955; Liess 1956). When the phalanges, metacarpals and metatarsals are considered in particular there is considerable divergence of opinion ; most authors who found more than one centre of ossification believed that this was rare, or the exception to the rule. Puyhaubert (1913) found single centres in phalanges; double centres have been described by Behrendsen (1897), by Davies and Parsons (1927), by Greulich and Pyle (1950) and by Brailsford (1953). K#{246}hlerand Zimmer (1956) regarded multiple centres of ossification as rare. It is interesting, however, that many illustrations in the literature depict, without comment, more than one centre in the various long bones of the hands and feet (Bruce 1907, Bertwistle 1924, Flory 1936, Meschan 1951, Venning 1956). Multiple centres ofossification have been described by Serres (1829, 1838), Hasselwander (1903), Redding (1926), Buxton and Knox (1927), Francis and Werle (1939), Liess (1955) and Caffey (1956); but Sawtell (1931) alone considered the frequency of the occurrence and this only in metatarsals. Observations on the fusion of multiple centres of ossification in an epiphysis-There are few details in the literature on the time elapsing before fusion of the centres occurs; the time factor is referred to as “ temporary “ (Liess 1956), “ a few weeks “ (Rambaud and Renault 1864), “ rapidly “ (Sawtell 1931 ; Shanks, Kerley and Twining 1939), “ soon “ (Francis and Werle 1939), “ later “ (Caffey 1956), “ about the sixth or seventh year “ (metatarsals) (Redding 1926), and “ after the tenth year “ (first proximal phalanx of foot) (Redding 1926). According to Caffey (1956), they fuse into “ a single large bony center which may remain uneven in density and irregular on the margins for many months before it becomes uniform in density and smooth on the edges.” Shanks, Kerley and Twining (1939) described rapid fusion and enlargement “into a round or oval mass of cancellous bone, which normally presents an irregular, nodular contour,” but also referred to the formation of a plaque of bone “whose deep surface in many epiphyses becomes markedly notched or cogged.” Observations on the spread of ossification within the epiphysis-According to Sawtell (1931), the first centres of ossification in the epiphyses of the first metatarsal and the first proximal