Muscles of the Ai-m. 



299 



A. and V. subscapularis 

 M. deltoideus 



M. coracobrachialis 

 M. biceps brachii 



M. pectoralis 

 major 



Tendo m. latissimi 

 dorsi 



INI. latissimus dorsi 



M. serratus anterior 



344. Fasciae of the right axilla, viewed from below. 



(The drawing corresponds to Fig. 343; the upper arm is in the horizontal plane.) 



Axilla (continued). The anterior surface of the in. pectoralis major is covered over 

 by the thin fascia pectoralis. This is more powerful lateralward and extends, from the lower 

 margin of the muscle to the lower margin of the mm. latissimus dorsi said teres major, trans- 

 versely across the axilla to form the fascia axillai-is. The latter is multiply perforated and 

 presents usually a more powerful, curved, fibrous band, the axillary arch, which varies much 

 in form and curvature, not infrequently contains muscle fibers and extends from the region 

 of the tendon of the m. pectoralis major to that of the m. latissimus dorsi: it is manifoldly 

 connected with these tendons. The fascia axillaris goes over behind into the thin fascia of the 

 mm. latissimus dorsi and teres major, in front into the thin covering of the m. deltoideus 

 and lateralward into the somewhat stronger fascia brachii. This forms a sheath for the 

 whole muscular mass of the upper arm and sends on each side a stronger strip to the margo 

 medialis and the margo lateralis humeri, the septtim intermuscular e mediale (0. T. internal 

 intermuscular septum) and the septum intermuscular e laterale (0. T. external intermuscular 

 septum), the former passing medianward and the latter lateralward between the m. triceps 

 brachii on the one hand and all the other muscles of the upper arm on the other. The 

 medial septum (see Figs. 348 and 353) lies immediately behind the insertion of them, coraco- 

 brachialis, behind the mm. brachialis and pronator teres and in front of the caput mediale 

 111. tricipitis brachii. The lateral septum (see Figs. 342 and 351) begins behind the insertion 

 of the m. deltoideus and runs behind the mm. brachiaUs, brachioradialis, extensor carpi radialis 

 longus, in front of the caput laterale and caput mediale of the m. triceps brachii. The muscles 

 mentioned arise in Darf from these septa. 



