8,6 



BOXES OF THE rrPER LIMB. 



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m 



anterior and posterior faces by lateral lines, slightly marked in the 

 upper and middle parts, BuT more prominent in the lower, where they 

 pass into the condylar ridges. Superiorly on its anterior aspect is the 

 bicipital groove, so named from lodging the long 

 Fig. 72. tendon of the biceps muscle : this groove, com- 



mencing between the tuberosities, descends with 

 an inclination inwards, and is bounded by two 

 rough ridges, the external and most prominent of 

 which gives attachment to the pectoralis major 

 muscle, the internal to the latissinlus dorsi j^id 

 teres major. Towards the middle of the shaft, on 

 the inner lateral line, is a rough linear mark where 

 the coraco-brachialis muscle is inserted, and lower 

 down there is a medullary foramen directed down- 

 wards into the interior of the bone. On the external 

 part of the shaft, near its middle, in a line ante- 

 riorly with the external bicipital ridge, is a large, 

 rough, and uneven surface, of a triangular shape, 

 the impression of the deltoid musde. Below this 

 lire external bicipital ridge is continued into a 

 smooth elevation which, descending on the front 

 of the shaft to the inferior extremity, separates an 

 external from an internal surface, while at the sides 

 two sharp edges, the external and internal condylar 

 ridijes spring from the eminences of the same name 

 and ascend for some distance, separating the 

 anterior from the flat posterior surface. About 

 the middle of the shaft externally, a broad depres- 

 sion, the spiral (jroovc, winds downv>'ards and for- 

 wards, limited above by the deltoid impression and 

 below by the external condylar ridge, and lodges 

 the musculo-spiral nerve and the accompanying 

 artery. 



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Fig. 72. — KiGiiT Humerus from behind. (A. T.) \ 



1, 3, 8, & 10, the same as in Fig. 71 ; 15, is placed above 

 the olecranon fossa. 



The inferior cxtremifij is much enlarged later- 

 ally, flattened from before backwards, and is curved 

 slightly forwards. Projecting on either side 

 are the external and internal condijlar eminences (the 

 condyles of most authors, epicondyle and epdrocldea of Chaussier), the in- 

 ternal of which is much more prominent than the external, and is slightly 

 inclined backwards. The inferior articular surface is divided by a ridge 

 into two parts. The external part, articulated with the radius, con- 

 sists of a rounded eminence directed forwards, called the capitelliun, 

 and a groove internal to it ; it does not extend to the posterior sur- 

 face. The internal part, the trochlea, articulates with the uhia, and 

 extends completely round from the anterior to the posterior surface 

 of the bone ; it is grooved down the middle like the surface of a 

 pulley, and is somewhat broader behind than in front ; anteriorly, its 

 margins are inclined downwards and inwards ; posteriorly, upwards 

 and outwards, and so that, seen from behind, it lies in the middle part 



