THE ANTIBRACHIAL MUSCLES. 



591 



The lower end of the upper fragment will then arrest flexion of the forearm by contact, 

 or may puncture the brachialis anticus, the bicipital fascia, and even the skin. 



The diagnosis of this fracture from luxation of the elbow (Fig. 575) can be 

 made by (a) the recognition of the relations of the three bony points, — the tips of the 

 two condyles and of the olecranon (page 306) ; {b) the presence of crepitus ; {c) the 

 disappearance of the deformity on extension and counterextension, and, usually, its 

 reappearance when extension is discontinued ; and {d) the greater freedom of exten- 

 sion of the forearm on the arm in fracture ; flexion may be limited, as above men- 

 tioned, by the contact of the upper fragment with the forearm at the bend of the elbow 

 and other points ; (e) the arm is shortened in fracture ; the forearm in dislocation. 



In separations of the lower humeral epiphysis (page 273) {a) the patient is a 

 child or an adolescent ; {b) there is muffled crepitus ; {c) the lower end of the upper 



Fig. 574. 



Fig. 575. 



Olecranon '-A 



Head of 

 radius 



Triceps 



Brachialis anticus 

 Biceps 



External condyle 



Olecranon 



Posterior luxation of elbow of right side. 



Displaced head of radius 



Dissection of preceding luxation, showing position 

 of bones. 



fragment has greater breadth and is more rounded than in fracture ; {d^ the line of 

 separation is nearer the end of the bone, and the anterior projection of the diaph- 

 ysis is on a level with the fold of the elbow ; in fracture it is usually above it 

 (Poland). 



Condylar fractures have been described (page 273), but it may be mentioned 

 here that the elevation of the internal condyle, if not corrected, causes the line of the 

 joint to incline inward instead of outward. If union takes place in that malposition, 

 the so-called "gun-stock deformity," or "cubitus varus" (in which the "carrying 

 angle" of the forearm with the arm is obliterated or changed to a similar angle 

 opening inward) results. 



The bursae about the elbow have been described (page 307). 



THE ANTIBRACHIAL MUSCLES. 



The muscles which belong to this group act primarily upon the bones of the 

 forearm or of the carpus and constitute the muscular substance of the forearm. Some 

 of them, however, have undergone a secondary extension into the hand and act as 



