THE ABDOMEN. ^17 



Tlie fore limb should now he elevated by means of an 

 iron fork, and tlie pectoral muscles dissected. Pectoralis 

 transversus is superficially situated, it blends witli its 

 fellow at tlie under part of the cariniform cartilage, and 

 anterior part of the sternum, being connected to these firmly 

 •at its anterior part by areolar tissue ; x^osteriorly, as far 

 as the lower extremity of the fifth rib, so that it has 

 free play over this surface ; from this its fibres run to 

 the inner side of the fore limb, and with levator humeri 

 become attached to the fibrous band running from the 

 inferior extremities of the humeral ridge to the infero-ex- 

 ternal part of the humerus. 



Anteriorly to the firm attachment of pectoralis trans- 

 versus is the originating point of sterno-maxillaris, above 

 which sterno-thyrO'hyoideus is attached to the cariniform 

 cartilage. Higher up pectoralis anticus is attached to the 

 lateral part of the sternum, extending as far back as about 

 the fourth sternal bone, and being slightly united to the 

 corresponding sterno-costal cartilages ; it runs upwards 

 to the antero-superior part of the scapula. 



Pectoralis mag^nus runs from the post ero -lateral part of 

 the sternum, and from the under surface of the ensiform 

 cartilage and from the anterior part of faschia superficialis 

 abdominis to the external and internal tubercles upon the 

 anterior part of the head of the humerus, where it is at- 

 tached with antea spinatus, and between which attachments 

 runs the superior cartilaginous tendon of flexor bracliii. 



By section of the pectoral muscles a quantity of loose 

 areolar tissue is shown, into the inferior part of which 

 subscapulo-hyoideus seems to be attached, gaining ap- 

 parently a very unsubstantial origin. The axillary artery 

 may now be seen running to the internal surface of the 

 shoulder- joint, while the axillary plexus of nerves is seen 

 sending off numerous trunks. The axillary artery after 

 being given off by the arteria innominata, winds round a 

 smooth surface on the anterior border of the first rib below 

 the inferior attachment of the scalenus muscle ; on gain- 

 ing the internal surface of the shoulder- joint it breaks up, 

 sending the humeral thoracic branch anteriorly to pector- 

 alis magnus and antea spinatus at their insertion ; the 

 anterior scapular between subscapularis and antea spina- 

 tus to the anterior dorsal fossa of the scapula ; the pos- 

 terior scapular or subscapular artery, which passes under 



