Anomalies of the Clavicle, with a Previously Unreported Variation

Abstract

CLAVICULAR dysostoses have been recognized for a long time. Morand (1) reported the first case in 1776, Barlow (2) the second group of cases in 1883, and in 1889 Hamilton (3) added his case to the literature, to make a total of 21. Since that time, a large number of cases have been recognized and reported. Familial incidence is common. McCurdy and Baer (4) reported an incidence of nine cases out of 13 individuals examined in three generations of one family. Villaret and Francoz (5) reported a woman and her three children, all of whom had clavicular anomalies. Langsmead (6) found 18 cases in four generations of one family. Stern (7) reported absence of clavicles in seven males of the same family whose four female members had normal clavicular development. Several theories have been expressed as to the probable etiology of some of these malformations. The most tenable one seems to be that of Kelley (8), who states that cranio-cleido-dysostosis is a congenital abnormality inherited as a dominant Mendelian factor affecting bones which are laid down originally in membrane. Interference with, or arrest of, development of bone from membrane is assumed to produce these abnormalities. Piersol (9) states that the ossification center of the clavicles is the earliest bony center laid down in the body and can be found during the sixth week of intrauterine life. Cartilaginous outline appears rapidly, and by the sixteenth week the clavicle is ossified and well developed (10). The center of the shaft ossifies first, so that in order to explain malformations it must be assumed that some irregularity in development has occurred within the first two months of intra-uterine life. Spriggs (11) states that although this ossification starts usually from a single centrally placed center, it is possible that ossification may occur also from other centers in the two ends of the clavicles. Thus, in cases in which arrested or absent center ossification occurs, bony growth is dependent upon that which takes place from the ends inward toward the middle. Defective clavicles are found to be associated usually with congenital anomalies elsewhere in the body. Fitz-Williams (12) found anomalies of the face or of the skull in 40 out of 60 cases reported in the literature. Deformities of ribs, scapula, pelvis, spine, and fingers are frequently reported (13) in conjunction with these clavicular defects. McCurdy and Baer (4), Stewart (14), Marie and Sainton (15), Léri and Trétiakoff (16), Stocks (17), Fitchet (18), and others (19 and 20) have reported malformations in the brain and central nervous system. In cases in which there has been interference with, or absence of, the normal ossification center, variations from a false joint to complete absence of clavicles may occur. These anomalies are dependent upon the amount of growth which takes place from the other centers of ossification in the lateral portions of the bone.