THE UPPER LIMB Zqrj 



The arteries of the thoracic region are the dorsal branches of the 

 intercostal arteries. Each dorsal branch passes backwards in com- 

 pany with the corresponding posterior primary division of a spinal 

 nerve. Before passing through the quadrangular space it gives off 

 a spinal branch, which enters the spinal canal through the inter- 

 vertebral foramen. After passing backwards it divides into an 

 internal and external branch, which have a distribution similar to 

 those of the nerve. 



The veins of the thoracic region terminate in the intercostal veins. 



The arteries of the lumbar region are the dorsal branches of the 

 lumbar arteries. Each accompanies the corresponding posterior 

 primary division of a spinal nerve, and its distribution is as in the 

 thoracic region. 



The veins of the lumbar region terminate in the inferior vena 

 cava. 



THE PECTORAL REGION AND AXILLARY SPACE. 



Landmarks — The outline of the clavicle cind acromion process 

 of the scapula are readily made out, and, in connection with the 

 acromion, it is to be borne in mind that the acromial epiphysis may 

 remain permanently detached from the spine, and so simulate a 

 fracture. The roundness of the shoulder is to be noted, this being 

 due largely to the deltoid muscle, but also in part to the head of the 

 humerus. Below the clavicle, at a point external to its centre, is a 

 depression, called the infraclavicular fossa, which indicates the 

 separation between the deltoid and pectoralis major. \Vhen the 

 arm is abducted and the finger pressed into this hollow, the inner 

 border of the coracoid process will be felt, and, if the finger be carried 

 outwards under the deltoid, the tip of that process can be made out. 

 In this region it is possible to compress the axillary artery against 

 the second rib, but this requires deep pressure. The coinrse of this 

 artery may be indicated by a line dra\NTi from the centre of the 

 clavicle to the inner border of the coraco-brachialis, the arm having 

 been raised to a right angle with the trunk, so as to define clearly 

 the outline of that muscle. The anterior and posterior folds of the 

 axi'la are to be observed, the anterior being formed by the lower 

 border of the pectorahs major, which practically coincides with the 

 line of the fifth rib, and the posterior by the latissimus dorsi winding 

 round the lower border of the teres major. The hollow between 

 these folds indicates the position of the axillary space, and it will be 

 seen to be narrow towards the arm, but wide towards the thoracic 

 wall. In the female the prominence formed by the manunary gland 

 is usually apparent on the surface of the pectorahs major. Its 

 vertical extent is from the second to the sixth rib, and it reaches 

 transversely from the side of the sternum to the anterior fold of the 

 axilla, except at the lower and outer part, where it extends beyond 

 this fold upon the serratus magnus. A little below and internal to 

 the centre of the mammary prominence is the nipple, which is sur- 



