ABDOMINAL MUSCLES. 327 



serratus major anticus ; and generally coheres to the pectoralis 

 major, intercostals, and latissimus dorsi ; which last covers the 

 edge of a portion of it extended from the last rib to tKe spine 

 of the ilium. It interdigitates by its five upper heads with 

 the serratus major anticus, and by the three lower with the 

 latissimus dorsi, where the latter arises from the ribs ; a slip 

 from the pectoralis covers the first or upper head. 



From these origins the fibres run obliquely downwards and 

 forwards, and terminate in the anterior half of the spine of the 

 ilium, and in a tendinous membrane, whose fibres are continued 

 in the same direction until they meet the fibres of the cor- 

 responding tendon of the other side, in a line which extends 

 from the ensiform cartilage to the symphysis pubis. 



This line is called linea alba, from its white appearance, 

 which is owing to the connexion of three tendons with each 

 other, without the intervention of muscles, namely, those of the 

 external and internal oblique, and the transversalis.* 



On each side of the line, two long narrow muscles, (the 

 recti.) are situated between these tendons, and do away the 

 white appearance ; but exterior to these muscles, the tendons 



only three in this subject. 14. Poupart's ligament. 15. The external abdomi- 

 nal ring ; the margin abovs the ring is the superior or internal pillar ; the mar- 

 gin below the ring, the inferior or external pillar; the curved intercolumnar 

 fibres are seen proceeding upwards from Poupart's ligament to strengthen the 

 ring. The numbers 14 and 15 are situated upon the fascia lata of the thigh ; 

 the opening immediately to the right of fifteen is the opening for the saphena 

 vein. 16. The rectus muscle of the right side brought into view by the removal 

 of the anterior segment of its sheath : * the posterior segment of its sheath 

 with the divided edge of the anterior segment. 17. The pyramidalis muscle. 

 18. The internal oblique muscle. 19. The conjoined tendon of the internal 

 oblique and transversalis descending behind Poupart's ligament to the pectineal 

 line. 20. The arch formed between the lower curved border of the internal 

 oblique muscle and Poupart's ligament ; it is beneath this arch that the sper- 

 matic cord and hernia pass. 



* According to Meckel, the linea alba performs the same office in the abdo- 

 men as the sternum does in the thorax, with this only difference, that it is not 

 formed of bone. The anterior tendons of the broad muscles are attached to it, 

 in the same way that the cartilages of the ribs are articulated with the sternum, 

 and the difference of tissue which exists between it and the sternum is attribu- 

 table to the general difference of structure between the abdominal and pectoral 

 cavities, the latter being formed almost entirely of osseous parts, whilst the 

 walls of the former are fleshy and tendinous. r. 



