332 



THE MUSCLES OF THE TRUNK. 



a less firm origin from Poupart's ligament than the portions above, which have a bony origin 

 (Morph. Jahrb., xi, 1886). 



The cremaster, a muscle peculiar to the male, consists of fibres lying in series 

 with those of the lower border of the internal oblique muscle. It has an external 

 and an internal attachment. The external attachment is to the inner part of 

 Poupart's ligament, and there its fibres are continuous with those of the internal 

 oblique muscle : the internal attachment, smaller and less constant, is by means of 



Fig. 294. THE TRANSVERSALIS MUSCLE AND POSTERIOR LAYER 

 OP THE SHEATH OF THE RECTUS. (Drawn by E. Wilson.) 



i 



VI X, sixth to tenth ribs ; 1 1, line of junction of in- 

 ternal oblique ; 2 2, cut edge of anterior layer of sheath of 

 rectus ; 3, inferior epigastric vessels crossing in front of the 

 semilunar fold of Douglas ; 4, superior epigastric vessels ; 

 above this, in the angle between the seventh costal cartilage 

 and the ensiform process, the lowest slip of the triangularis 

 sterni is seen. The position of the outer edge of the rectus is. 

 indicated in its upper part by the clotted line. 



a tendinous band to the spine and crest of the pubis, 

 close to the insertion of the internal oblique muscle. 

 The superior fibres of the muscle extend between 

 these attachments in a series of successively longer 

 loops, descending in front of the spermatic cord, a 

 few of them reaching as low as the level of the 

 testicle ; the remaining fibres, the greater number 

 of which descend from the outer attachment, and 

 only a few from the inner, spread out below and 

 are embedded in the substance of a fascia termed 

 cremasteric, which adheres to the fascia propria of 

 the testicle. Sometimes the only fibres developed 

 are a bundle descending from the outer attachment. 



In the female there may be almost constantly detected 

 a few fibres descending on the round ligament of the 

 uterus, which correspond with the last- mentioned fibres- 

 of the cremaster muscle of the male. 



The transversalis abdominis muscle, sub- 

 jacent to the internal oblique, arises from the inner 

 surface of the cartilages of the six lower ribs by 



fleshy slips which interdigitate with the costal attachments of the diaphragm (fig. 288, 

 p. 321), from the transverse processes of the lumbar vertebrae by a strong posterior 

 aponeurosis, from the inner margin of the crest of the ilium in the anterior two-thirds 

 of its extent, and from the outer third of Poupart's ligament. The greater part of the 

 fibres have a horizontal direction, and extend forwards to a broad aponeurosis in front ; 

 the lowest fibres curve downwards like those of the internal oblique, with which they 

 are usually closely united, and are inserted into the front of the pubis and into the 

 ilio-pectineal line, through the medium of the conjoined tendon already described as 

 common to this muscle and the internal oblique. 



The anterior aponeurosis of the transversalis muscle commences in the greater 

 part of its extent at the distance of about an inch from the outer border of the 

 rectus muscle ; but at its upper extremity it is much narrower, and there the 

 muscular fibres of opposite sides approach nearly to the middle line behind the recti 

 muscles. In its upper two-thirds it becomes united with the posterior layer of the 

 aponeurosis of the internal oblique, forming the posterior wall of the rectus-sheath ; 



