Reprinted from the.AMERICAN JoURNAL OF PHYSICAL ANTHROPOLOGY. Vol. V, N~ . 1, January-March, 1922 OBSERVATIONS ON AGE CHANGES IN THE SCAPULA A PRELIMINARY NOTE BY WILLIAM WASHINGTON GRAVES, M.D. Anatomical Laboratory, Western Reserve Universi: y, Cl~eland, Ohio L Y I ICJJ OBSERVATIONS ON AGE CHANGES IN THE SCAPULA A PRELIMINARY NoTE WILLIAM WASHINGTON GRAVES, M. D. St. Louis (/<'rom the Anatomical Laboratory, W estern Reserve University, Cleveland, Ohio ) In 1920 while further studying scapular character variations, through the courtesy of Ptof. T. Wingate Todd (Hamann Museum, Department of Anatomy, ·western Reserve University), the writer became impressed with a series of changes in the scapula, which appears to be intimately associated with advancing years after maturity of the bone. The human skeletal material in the Hamann J\!I usew11 is exceedingly valuable for the investigation of bone-age changes in general. It comprises at the present tim e approxim ately 750 complete skeletons ranging from birth to 88 years, of known age, sex and stock, and it is growing at the rate of 100 such skeletons a year. Data on age, sex and stock are accessible in all, and data on clinical history, as well as clinical or anatomical causes of death, are accessible in a large number of these complete skeletons. The scapula is a bone peculiarly adapted to the study of skeletal age changes in any age period. In the first place, its several centers for ossification , uniting in various parts of the bone in sequence at different ages and finally producing an adult scapula in every detail by approxi­ mately the 22nd year of life, give to t his bone peculiar importance in estimating the bone age of skeletal material during growth periods up to maturity. In the second place, its numerous anatomical and archi­ tectural characters, (each of which shows wide variation) its thickened borders limiting its greatly thinned body, its angles, its spine and acro­ mion, its coracoid process, its glenoid, its clavicular facet, its relative fr eedom from weight influences, its relation to a number of muscles and its peculiar vascular supply, all combine to give to the scapula definite values in studies of skeletal age changes during advancing age periods after the 25th year of life. Regardless of whatever values the scapula may disclose through further investigations, we must not forget that it is only one of many skeletal features showing the ravages of time. Therefore, its worth as a "time-marker" should only be evaluated in connection with other bones and when possible with other tissues. Au. J. PaYS. ANTBROP., VoL V, No. !. 21 22 WILLIAM WASHI NGTON GRAVES In a survey of age changes shown in scapulae, it is found that several important features must be investigated and discussed. The relation of the changes identified with age t o the type of scapula from birth onward, t o certain scapular variations, to human stock, to sex and possibly to disease, must each , in due course, receive attention. The reasons for considering age changes in relation to possible stock, sex and disease differences are obvious, but one would ordinarily suppose that no valid reasons could be given for considering age changes in relation to scapular variations and types, yet such relations are probably equally impor­ tant . In this connection, attent ion is called to the writer's communication on "The T ypes of Scapulae" (AME RI CAN JouRNAL OF PHYSICAL ANTHRO­ POLOGY, Vol. IV., No. 2, p. 111.) in which is pointed out certain morpho­ logical differences present in the convex, straight and concave types. The writer has secured some data in reference to age changes on 589 pairs of scapulae, embracing convex, straight and concave types from white and negroid stock in the H amann Museum, and he has more int imately studied the age changes in 139 pairs of scapulae of the convex type from the white males, ranging in years from 18 t o 88. It seems advisable thus early in the investigations to defin e and describe in outline some of the gross features in the scapula which show relation to age after maturity. SCAPULAR STRUCTURES INVOLVED IN AGE CHANGE PROCESSES Age changes in scapulae appear to be manifestations of two diametri­ cally opposed processes: the one an ossifi cation process ; the other an atrophic process; both occurring after maturity of the bone. The chief structures which show age changes attributed t o an ossification process with advancing years are: (1) The articular cartilage in its relation to the bony glenoid margins and possibly also, in the old, of the Labrum glenoidale in its relation to the art icular cartilage; (2) The cartilaginous structure covering the margin and surface of the clavicular facet , and possibly of the inter-articular cartilage and joint capsule; (3) The under surface and t ip of the acromion in their relation to the coraco-acromial ligament, to the subacromial bursa and to other contiguous structures ; (4) The trapezial smooth surface at the base of the spine, and possibly its relation to the t rapezial bursa wall ; and (5) The cristae in their rela­ t ion t o subscapular intermuscular septa. The structures which show age changes attributed to an atrophic process discernible mainly in the thinned body of the bone are: AGE CHANGES IN THE SCAPULA 23 (1 ) Diminution and eventually loss of surface vascularity; (2) Diminution and alteration in deep vascularity; (3) The occurrence of localized areas of bone atrophy; (4) A buckling or pleating of the thinned body mainly of its dorsal surface above and below the spine, and (5) Distortion of the thinned body mainly below the spine. Age changes attributed to ossification are equally discernible in scapulae whether fixed (i. e., embalmed) or unfixed. If, however, the bones have been macerated without previous fixation (embalming), the picture of the changes in superficial and deep vascularity is altered, but the other features incident to an atrophic process are readily discernible in fix ed and unfixed bones. With the protocols of scapulae to be sub­ mitted in the fin al paper on changes attributed to age the specific differences depending upon fix ation and non-fixation will be pointed out. The following outline of definitions and descriptions of gross age-change features is based solely on bones from bodies adequately "fix ed" for dissecting purposes. AGE CHANGES ATTRIBUTED '1'0 AN OSSIFICA'fiON PROCESS AFTER MATURITY I. Glenoid lipping implies any degree of ossification, in whole or in part, of what appears primarily to have been the articular cartilage in its relation to the glenoid margins or to the immediately adjacent sur­ faces. Depending upon the bone age of the individual, the lipping may involve the ventral, inferior, dorsal or superior margin and usually in the order named or it may involve the entire marginal surface. When the entire glenoid marginal surface shows lipping it may be rather uni­ form or it may be distinctly irregular. The lipping usually begins, in the early thirties at the notch or depression which is located at the junc­ tion of the upper and middle thirds of the ventral glenoid margin (Pl. I., No. 535). The lipping may be slight, moderate or marked. When it involves the entire marginal surface, it may be flaring, broad at the top thus greatly increasing all original glenoid diameters (Pl. I, No. 551) or it may have nearly vertical walls, increasing the depth of the original bony glenoid cavity (Pl. I , No. 535). In some bones especially those with flaring glenoid margins, the original bony margins seem to be encased, as it were, in new bone (Pl. I, Fig. 551). Rarely the lipping may invade, in part, the articular cartilage near any portion of the glenoid margin. No difficulty should be experienced in recognizing the lipping, if one remembers that at maturity the bony glenoid margins are nowhere roughened, sharpened or elevated. The margins at this 24 WILLIAM WASHINGTON GRAVES period are relatively smooth and everywhere more or less rounded; less so, however, at the ventral margin than at any other point. When lip­ ping is present, it is easily detected by vision and touch, and when extensive also by transmitted light. Holding a margin of a glenoid in front of a window or an electric-light bulb, one often notes that the ossified cartilage is translucent, and there is often a definite line of demarcation between the lipping and the former bony margin. Whether in pre-senile and senile scapulae t he Labrum glenoidale becomes in­ volved, can be determined only by further study .1 II. Clavicular facet lipping implies ossification of the cartilage covering the margins and surface of this facet and possibly also of the inter-articular cart ilage and joint capsule. When lipping is present, it is seldom uniform, and in some cases it involves the entire margin (Pl. II, No. 535 lower). In the old and relat:vely old, there is often a marked deformity of this facet, not only of its margins but likewise of its articular surface. When such exists, it is strongly suggestive of a former osteo-arthritic process. Nevertheless, the deformity has been found thus far only when associated with other definite scapular age changes. III. Acromial under-surface and tip ossification implies the presence of an elevated plaque of bone varying in form, size and thickness, sit­ uated on the under-surface of the acromion within the area bounded by the outer margin of the acromion and a mesially curved line beginning at the metacromion and ending just lateral to the clavicular facet (Pl. II, Nos. 806, 535).