THE UPPER LIMB 



307 



linor over about its middle third. Above the latter muscle the 

 osto-coracoid membrane enters into the anterior wall. The lower 

 (Order of the anterior wall, formed by the pectoralis major, con- 

 titutes the anterior fold of the axilla. The posterior wall is formed 

 rom above downwards by the subscapularis, teres major, and latis- 

 imus dorsi. Towards the arm the tendon of the latissimus dorsi 

 ies in front of the teres major, the latter muscle extending a little 

 ower down. The posterior wall is longer than the anterior, and its 

 Dwer border, formed by the folding of the latissimus dorsi round the 

 eres major to get in front of it, forms the posterior fold of the axilla, 

 rhe inner wall is formed by the upper four or five ribs, with their 

 Qtercostal muscles, and the corresponding serrations of the serratus 



Brachial Plexus 

 Cejphalic Vein \ 



Muscnlo-cutaneoas Nerve 

 Deltoid 



Trapezius 



Suprascapular Vessels 



Transverse Cer\-ical Artery 



Posterior Belly of Omo-hj-oid 



Scalenus Anticus 



Stemo-ckido-iiiastcnci 



""Clavicle in section 



I 



" Snbclavius 



--Axillary Artery 

 ^- Axillary Vein 

 ^~ Pectoralis Major (cut) 



'Pectoralis Minor 



'\ ^ ' \ \ Outer Head of Median Nerve 



Nerve of Wrisberp \ N ^ ^ 



Axillary Vein \ \ Inner Head of Median Nerve 

 Ulnar Nerve 



Internal Cutaneous Nerve 



176. — ^The Axillary Space, after Reflection of the Pectoralis 

 Major, and the Subclavian Triangle. 



fagnus. The outer wall, which is very circumscribed, is formed by 

 le upper part of the humerus and the common origin of the coraco- 

 rachialis and short head of the biceps. 



Contents and their Position. — The axillary vessels and the nerves 

 bich arise from the brachial plexus lie for the most part along the 

 iter wall. The thoracic axis and the long thoracic artery pass to 

 le anterior wall, the former above the pectoralis minor, where it 

 erces the costo-coracoid membrane, the latter along the lower 

 irder of that muscle. The subscapular artery lies on the posterior 

 ^all, where it passes inwards on the lower border of the subscapu- 

 ^ris. The posterior circumflex artery lies for a short distance on the 

 1)sterior wall, but soon passes back\vards between the subscapularis 



1 teres major. The anterior circumflex artery passes outwards 



