TEAXSVERSALIS ABDOMIN1S MUSCLE. 253 



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 greatest number of which descend from the outer attachment, 

 and a few from the inner, spread out inferiorly 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 descend- 

 ing from the outer attachment. 



In the female there may be almost constantly detected a small bundle of 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, subjacent to the internal oblique, 

 arises from the inner surface of the cartilages of the six lower ribs j from a 

 strong aponeurosis attached to the lumbar vertebrse ; from the inner margin 

 of the crest of the ilium in the anterior two- thirds of its extent, and from 

 the iliac 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, and are 

 inserted into the front of the pubes and into the 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 this aponeurosis is 

 much narrower, and there the muscular fibres of opposite sides approach 

 nearly to the middle line behind the recti muscles. In the greater part of 

 its extent it becomes united with the posterior layer of the aponeurosis of 

 the internal oblique forming the rectus sheath, and inferiorly, where that 

 aponeurosis passes entirely in front of the rectus muscle, it remains blended 

 with it, and passes likewise in front of that muscle. 



The posterior aponeurosis of the transversalis muscle extends backwards 

 between the last rib and the iliac crest, and opposite the outer border of 

 the erector spinse muscle, is continuous with the apoueurotic structure which 

 passes to the vertebral column in three layers, commonly named the pos- 

 terior, middle, and anterior layers of the lumbar aponeurosis. The posterior, 

 or most superficial, of these layers is that previously referred to as being 

 connected with the tendons of the latissimus dorsi and serratus inferior 

 muscles, and which is attached to the spinous processes of the vertebrae. The 

 middle layer, which is the strongest, is attached to the tips and margins of the 

 lumbar transverse processes, and lies between the erector spinse and quadratus 

 luxnborum muscles. The remaining deepest layer, comparatively thin, passes 

 in front of the quadratus lumborum muscle to the roots of the lumbar 

 transverse processes, and at its upper part, where it increases in thickness 

 and is connected with the last rib, it forms, as already mentioned, the 

 ligamentum arcuatum externuni of the diaphragm. 



The triangularis sterni, when viewed from behind, along with the transversalis 

 abdominis, has the appearance of being a continuation of that muscle upon the 

 wall of the chest, above the diaphragm : hence the name of transversalis thoracis t 

 which has sometimes been given to it. 



The rectus abdominis is a long Eat muscle, consisting of vertical fibres, 

 situated at the forepart of the abdomen, within a tendinous sheath formed 

 in the manner already described in the account of the aponeurosis of the 



