THE AXILLARY ARTERY 



569 



THE AXILLARY ARTERY 



The term axillary is applied to that portion of the main arterial stem of the 

 upper limb that passes through the axillary fossa. The axillary artery [a. axillaris] 

 (fig. 464) therefore is continuous \\\i\\ the subclavian above and with the brachial 

 below. It extends from the lateral border of the first rib to the lower edge of the 

 teres major muscle, and has the shoulder-joint and the neck of the humerus to 

 its lateral side. When the arm is placed close to the side of the body, the artery 

 forms a gentle curve with its convexity upward; but when the arm is carried out 

 from the side at right angles to the trunk in the ordinary dissecting position, the 

 vessel takes a nearly straight course, which vnW then be indicated by a line drawn 

 from the middle of the clavicle to the groove on the medial side of the coraco- 

 brachialis and biceps muscles. The axillary arterj^ is at first deeply placed 

 beneath the pectoral muscles, but in its lower third it is superficial, being covered 



Fig. 464. — The .\xillary Artery. (After Spalteholz.) 



Axillary artery 

 Thoraco -acromial artery 

 Acromial branch I 



Deltoid branch \ i " 



Musculo-cutaneous nerve \ j 



Circumflex humeral artery i i [ 



I I 



Coraco-brachial muscle 



Deltoid muscle 

 Pectoralis \ 



major muscle 



Axillary vein 



Median 

 nerve I 

 Braciiial vein 



/ 



Deltoid branch' 



Ulnar nerve 

 Brachial cutaneous/ 

 and medial anti-' 

 brachial nerves / 



Axillary nerve / 

 Subscapular artery 

 Latissimus dorsi muscle ' 



Circumflex scapular artery 



Third rib 



I 

 Pectoralis minor muscle 



Pectoral branches 



Lateral thoracic artery 



Dorsal thoracic artery 



only by the skin and the superficial fascia and deep fascia. It is divided into 

 three parts, first, second, and third, according as it lies respectively above, 

 beneath, or below the pectoralis minor. 



The First Part of the Axillary Artery 



The first part of the axillary artery extends from the lateral border of the first 

 rib to the upper border of the pectoraUs minor. It measures about 2.5 cm. (1 in.) 

 in length. 



Relations.; — In front it is covered by the skin, superficial fascia, lower part of the platysma, 

 the deep fascia, the pectoraUs major, the coraco-clavicular (costo-coracoid) fascia, the sub- 

 clavius muscle and the clavicle when the arm hangs down by the side. The cephalic and 

 thoraco-acromial veins, the external anterior thoracic nerve, and the axillary lymphatic trunk, 

 cross over it. A layer of the deep cervical fascia which has passed under the clavicle also 

 descends in front of it. 



