300 



APPLIED ANATOMY. 



children, though not infrequently described as separations of the epiphysis are 



probably more often true bony fractures. 



Humerus. The lower end of the humerus ossifies by four centres. Three of 



them, those for the lateral (external) condyle, capitellum and outer portion of the 



trochlea, and inner portion of the trochlea, appear at the twelfth, third, and twelfth 



years and fuse and unite with the shaft at about the six- 

 teenth year. The fourth, for the internal condyle, appears 

 at the fifth and unites about the seventeenth or eighteenth 

 year. The epiphyseal line runs close to the edge of the 

 articular surface and is below the level of a transverse line 

 joining the upper edges of the two condyles (Fig. 315). 

 A true epiphyseal separation would thus be intra-articular 

 and would involve comparatively only a thin shell of the 

 articular surface. As already stated most of the cases 

 regarded as epiphyseal separations are probably true 

 supracondylar fractures. 



Destruction or removal of the epiphyseal cartilage 

 is, of course, if possible, to be avoided in operations in 

 young children, as otherwise interference with the growth 

 of the bone will occur. 



Ulna. Most of the olecranon process is a direct 

 outgrowth from the shaft of the ulna. At about the 

 tenth year a thin shell forms at its extremity which 

 unites at the sixteenth year. Therefore fractures which 

 pass through the bottom of the greater sigmoid cavity 

 are not separations of the epiphysis but true fractures. 



Raditis. The upper articular surface of the radius 

 has a centre of ossification which appears from the fifth 

 to the seventh year, and unites at the eighteenth to 

 twentieth year. 

 There is also a centre for the tubercle. Surgical writers as a rule do not speak 



of epiphyseal separations of the upper ends of the radius and ulna. 



FIG. 315. Epiphysis of the 

 lower end of the humerus; unites 

 with the shaft at about the seven- 

 teenth or eighteenth year. 



DISEASE OF THE OLECRANON BURSA. 



Between the skin covering the olecranon process and the bone is a bursa, 

 which, from its exposed position, is not infrequently diseased. It lies in the subcu- 

 taneous tissue and resembles in all respects the bursa in front of the patella. In those 

 whose occupation causes them to rest frequently on the elbow, this bursa becomes 

 enlarged, hence the name "miners elbow." The bursa lies on the posterior surface 

 of the bone and extends from the tip of the olecranon downward in the direction of 

 the forearm. Excision is the most efficient treatment. There are no dangerous 

 structures to be encountered in the operation because the bursa does not communi- 

 cate with the joint. The position of the ulnar nerve should be borne in mind. It 

 can readily be avoided and usually is not seen. There is sometimes another bursa 

 on the upper surface of the olecranon just below the insertion of the triceps. It is 

 rarely affected. 



DISEASE OF THE ELBOW-JOINT. 



The elbow-joint, like others, is affected with rheumatoid and tuberculous dis- 

 ease. The former frequently causes ankylosis, while tke latter frequently causes 

 suppuration. The joint becomes distended and enlarged. The bony prominences 

 of the elbow, while they may not be visible, nevertheless can usually be recog- 

 nized by palpation. The lateral ligaments are stronger than the anterior and pos- 

 terior, hence the swelling is most marked in front and behind. As the internal lateral 

 ligament is stronger than the external lateral, swelling will be more marked on the 

 outer side and the medial (internal) condyle will be more easily recognized than the 

 lateral (external). 



