SHOULDER SCAPULAR REGION 87 



Dissection. Pull the long head of the biceps out of the 

 intertubercular sulcus. Separate the tendon of insertion of 

 the latissimus dorsi from the anterior surface of the teres major, 

 noting the small fibrous slip which passes from its inferior 

 margin to the fascia on the long head of the triceps muscle 

 (Fig. 1 6) ; then follow the tendon of the latissimus to its 

 insertion into the floor of the intertubercular sulcus. The 

 tendon of the latissimus is more or less adherent to the teres 

 major, but near the humerus a small bursa frequently intervenes 

 between the two tendons. Now examine carefully the insertions 

 of the pectoralis major, the latissimus dorsi and the teres major. 



Insertions of the Pectoralis Major and Latissimus Dorsi. 

 As the pectoralis major passes to its insertion into the lateral 

 lip of the intertubercular sulcus it lies anterior to the great 

 vessels and nerves of the axilla, to the two heads of the biceps 

 humeri, and to the coraco-brachialis, whilst the latissimus dorsi 

 lies behind those structures. The teres major accompanies 

 the latissimus dorsi as far as the medial lip of the intertuber- 

 cular sulcus. It therefore does not pass behind the long head 

 of the biceps humeri. 



The tendon of the pectoralis major consists of two laminae. 

 A separation of the clavicular and sternal portions of the 

 muscle will bring both laminae into view, and the following 

 points should be noted in connection with them : (a) that 

 they are continuous with each other below, or, in other words, 

 that the tendon is simply folded upon itself; (<) that the 

 posterior lamina extends to a more proximal level on the 

 humerus than the anterior, and that a fibrous expansion pro- 

 ceeds proximally from its superior border, to seek attachment 

 to the capsule of the shoulder-joint and the lesser tubercle of 

 the humerus ; (c) that the lower border is connected with the 

 fascia of the arm. 



The narrow, thin, flat, band-like tendon of the latissimus 

 dorsi lies in front of the insertion of the teres major, but does 

 not extend so far downwards. Therefore the teres major is 

 the lowest muscle in the lateral part of the posterior wall of the 

 axilla, and consequently the last muscle of the posterior axillary 

 wall upon which the axillary artery rests. The slip of fascia 

 which passes from the lower margin of the tendon of the 

 latissimus to the fascia on the long head of the triceps is of 

 interest inasmuch as it represents the dorsi -epitrochlearis 

 muscle of other animals. 



Dissection. Depress the upper border of the subscapularis 

 as it passes below the coracoid process, and expose the subscapular 



