OCR Text |
Show OF THE PLATE-g. X? Pl'l‘llc‘ 1": D, The upper portion of the patella. In the case from which the first figure was taken, the portions of the pad tells still lay on the surface of the thigh bone, and playing over the head of FIG. 2. i i[ . 'l l', w that bone in its motion, threw the action of the tendon offfrom the centre of @yflllllliiiiiiii ‘iiii‘ii‘ii fl/f/f "~" the joint, increasing consequently the force of the muscle. The nearer the ‘ ‘ fractured portions of the bone are to each other, the stronger is the union "murmur .., betwixt them. In the second fig. the intermediate portion of new ligament is longer and proportionably Weaker, and, in the next plate, the cfl'ect ofthi's will be seen. »}_. ""\‘.*.'\‘l W‘"\'w"‘ PLAN. FIG. 3. A, The lower head of the thigh bone. ,.\WJW//"" B, The head of the tibia. C, The patella fractured. I Ii' A 5.7 7', mum . I M l \\/' W .‘i‘si 2/ I}, i. i 'i i n; This plan SheWS that when the patella is mounted on the convex surface of the articulating head of the thigh bone, the sudden and violent action of the muscles on the thigh may snap it across, without the knee touching the ground. « g-v..-'l P L A N. F1 G. 4-. . This plan is designed to shew the similarity in effect of the fracture of the olecranon at the elbow joint with that of the fracture of the patella. A, The humerus. B, The ulna. C, The olecranon broken 03'. D, The cavity into which the point of the olecranon should enter, when \I the arm is distended in the natural state of the parts. If the arm be kept bent during the cure, then the space marked by the dotted line betwixt the olecranon and the ulna will be occupied by callus or a;"h new bone, and it will then be impossible to extend. the arm, for before the ~/ "7/ , ilk/5W ‘1‘ x 47'!" if" 77» ' fore arm is extended, the olecranon, C, will strike on the back of the hume- rus, A. We may easily understand, too, that if the arm be too much extended, the ulna, B, will press the olecranon, C, out of the cavity, D; con~ sequently, after the union, the natural check to the extension of the arm will be lost, and therc will be danger of a strain of the elbow joint, 1mm the insufficiency of the anterior ligaments to restrain the motion backward. PLATE V. This plate represents the fore part of the knee joint torn open. It is intended to exemplify the consequences of allowing the upper portion of the patella to be drawn up by the action of the quadriceps tremor-is muscle. .l r "v! «"- 'I} o'd...1.-u~.v,-v"-.- warm D, The ligament of the patella, which connects the lower fractured portion of the bone with the tibia. E, The muscle inserted into the upper portion of the patella. |