356 



PR A CTJCA L AN A TOM \ '. 



this muscle and the triceps, teres minor, infraspinatus, and trapezius below. 

 Now, with a sharp scalpel cut the scapular origin of the deltoid, along the whole 

 length of the inferior border of the spine and acromion process of the scapula. 

 (Fig. 249.) Turn the muscle forward and see, in a mass of connective tissue 

 and fat, the posterior circumflex artery and circumflex nerve emerging from the 

 quadrangular space. (Fig. 249.) Trace the circumflex nerve to the deltoid and 

 teres minor muscles. Trace the deltoid to its insertion into the deltoid depres- 

 sion on the outer surface of the humerus, middle one-third. Take note of the 

 triangular shape of a number of muscles about the shoulder. 



The Teres Major and Latissimus Dorsi (Figs. 250-253). Divide the 

 connective tissue between these two muscles. Trace them under the scapular 



Infra-spinatus, cut 

 ACROMIAL PROCESS 



Suprascapular artery 

 SPINE OF SCAPULA 



Teres minor 



Superior profunda artery 



Posterior circumflex artery 

 I Deltoid, reflected 



Infra-spinatus, cut 



Teres major 

 Dorsal scapular artery 



Branch of dorsal scapular arferi/ 



'\l-:it\'E TO TERES MINOR 



'SCI Y, O-SPIRA L NER VE 

 Outer head of triceps 



EXTERN. \ I. (TT.i NEO US 

 BKAM'II <,! 

 MUSCULO- 



xriU.il. NERVE 



Lone head of triceps 

 CUTANEOUS BRANCH OF CIRCUMFLEX NERVE, ( IT 



FIG. 249. THE POSTERIOR CIRCUMFLEX ARTERY. 

 (From a dissection by Mr. Horner in the Museum of St. Bartholomew's Hospital.) 



head of the triceps to the humerus. These muscles form the lower bourn 

 of both the quadrangular and triangular spaces. They are inserted as follous : 

 The latissimus dorsi into the bottom of the bicipital groove as high as the lesser 

 tuberosity of the humerus ; the teres major into the inner lip of the bicipital 

 groove for two inches in length. Note that both these tendons are inclosed in a 

 rather tough sheath of connective tissue. 



The teres minor (Figs. 251 and 253) is separated near the humerus from 

 the teivs major by the scapular head of the triceps. Divide the connective 

 tissue between the teres minor and the infraspinatus above and the teres major 

 below. (Fig. 250.) The teres minor arises from the axillary border of the 

 scapula. It is synergistic in its action to the deltoid and derives its nerve-supply 

 from the same circumflex nerve. It is inserted into the lowest facet of the 



