MR. PRESIDENT, LADIES, AND GENTLEMEN,-Although much work has been done in connexion with the general and local pathological conditions which predispose to fractures of the long bones, yet perhaps sufficient attention has not been paid to their exact anatomy, especially as regards their internal structure. It was not without much hesitation that the subject of the two lectures, which I have been called upon to deliver in this College was chosen, and when one reflects that it is frequently said

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... at anatomy is a limited subject and that no new discovery can be made in it, this hesitation must be excused. Moreover, so many great names have been, and still are, associated with the question of fractures, that there seems little to say concerning a subject about which Hunter, Astley Cooper, R. W. Smith, and Bennett have written and spoken. There seems still less to say concerning a subject which has been dealt with so thoroughly and successfully by x ray photographers. Bnt, Sir, the preface to your work on the anatomy of joints has encouraged me to proceed with the subject, and, after all, so long as the cause of any fracture in any individual remains unknown, so long is there room for, at all events, some reflection as to the exact cause of a particular fracture. j I propose to deal with fractures of the long bones, but as the anatomical conditions governing the results of these fractures cannot be considered without a reference to ligaments I shall have no hesitation in raising the question of the functions of certain important ligaments. In the ends of the bones of an ordinary adult man there are developed definite lamelise running in the main direction along which pressure is transmitted. Certain other lamellse are also developed gradually crossing these pressure lamel]ae at right angles. These are known as tension lamel]a3. Their presence generally increases the elasticity and therefore the strength of the bone. (Fig. 1.) In the young person as well as in the old Showing pressure and tension lamellae in os calcis. P. L., Pressure lamellm. T. L., Tension lamellae. these pressure lamellse are not well seen, nor are the tension lamellas. In the young person the cancellous tissue at the ends of the long bones is so dense and the meshes are so fine that the pressure anr' tension lamellas can hardly be demonstrated. In the old person the bone fibres are so obscured by the presence of fat that they are very difficult to discover. Although the fat is deposited generally in the substance of the cancellous tissue, yet it is apt to occupy certain definite positions and to occur in relatively large masses. For example, such definite masses may be found in the lower end of the radius, the upper end of the humerus, the inner No. 4416. end of the clavicle, and the upper end of the femur. In the tibia, too, a small mass of fat is developed at the root of the internal malleolus. These masses of fat appear to develop in the part of the bone which is least subjected to pressure. In the case of the clavicle and the femur as well as the upper end of the humerus they appear to develop between definite series of lamelloe. I propose in my first lecture to deal with fractures of the neck of the thigh-bone. I shall first endeavour to show ! from recent specimens that these fractures have perfectly definite causes, the statement of which depends to a large extent upon the knowledge of the internal structure of the upper end of the femur. A stujy of the internal structure of the upper end of the femur throws such a flood of light upon certain deformities that I shall have no hesitation in referring also in some detail to the conditions met with in coxa vara and in old unreduced dislocations of the hip-joint. The usual conception of the internal structure of the upper end of the femur is that which is gathered from a coronal section such as this (Fig. 2) . Now in this section is shown a series Showing chief seties of lamellae in coronal section of upper end of femur, P. L., Pressure lamellae. T. L., Tension lamellee. Scale life size. of arching lamellx passing from the inner and outer surfaces of the shaft of the femur into the trochanteric region, the neck and the head. Those from the inner surface pass upwards into the region of the great trochanter and also into the lower part of the neck and so by additional series of lamellae to the upper surface of the head. Those lamellse from the outer surface pass also upwards into the great trochanter and then vii the upper part of the neck of the femur to the lower portion of the head of the same bone. Now there are a series of lamellm which do not thus form an arch and which pass from the upper surface of the head to the lower surface of the neck and thus to the compact layer on the inner surface of the shaft of the femur. The spur of bone which is represented in this obliquely transverse section of the upper end of the femur and which is known as the calcar femorale, or Merkel's, or Adams's arc is said to lie in the lines of pressure passing from the head and neck to the shaft of the bone. In order to study this spur of bone transverse sections are frequently made of the upper end of the femur, but such a section gives little indication of its position and none of its true function. Its position and function may be made out in a much more satisfactory manner by the reference to sections which are obliquely transverse-that is, parallel with the long axis of the neck. (Fig. 3. ) These sections show, in addition to the calcar the position of which will be referred to later, a most important series of lamellae passing from the anterior and inner part of the head of the femur to the posterior surface of the neck. These are very definitely shown in many sections which have been made ; but it is only Q