THE RABBIT. 345 



410. The teres minor, a small muscle exposed by the 

 removal of the preceding : it arises from the ventral third of 

 the glenoid border of the scapula, and is inserted into the 

 greater tuberosity just below the insertion of the infra- 

 spinatus. 



In the upper arm. 



411. The extensor parvus antibrachii (ex.p.a), a 

 small flat muscle lying on the inner face of the upper arm 

 about midway between its anterior and posterior borders : 

 it arises by a flat tendon from the fascia of the upper arm, 

 and is inserted into the olecranon : cut it through and 

 reflect. 



412. The triceps, or chief extensor of the fore-arm: 

 a very large muscle consisting of four parts or heads 



(a). The middle or long head (anconeus longus, tr l ), 

 a large fleshy mass forming the posterior edge of the upper 

 arm : it arises from the ventral third of the glenoid border 

 of the scapula, and is inserted into the olecranon : divide 

 and reflect. 



(If). The short or outer head (anconeus brevis, tr-) 

 is situated on the outer face of the upper arm just in front 

 of the preceding : it arises from the outer surface of the 

 shaft of the humerus, and is inserted with the longhead into 

 the olecranon : detach from its origin and reflect. 



(c). The inner head (anconeus internus, /y 3 ) occupies 

 a similar position on the inner face of the upper arm, lying 

 between the anconeus longus and the biceps (413): it 

 arises from the posterior surface of the shaft of the humerus, 

 and is inserted into the olecranon : detach from its origin 

 and reflect. 



(d). The accessory head (anconeus quartus, tr 4 ) is a 

 very small, fan- shaped muscle, exposed by reflection of the 

 anconeus longus and internus, on the inner faee of tho 



