204 MYOLOGY. 



thick, and occupies the flank ; the aponeurosis commences at the 

 linea semilunaris, its fibres blending with those of the external 

 oblique. 



Attachments. — Supero-posteriorly, to the anterior spine of the 

 ilium, whence its fleshy fibres radiate ; a portion is attached to 

 the transverse processes of two or three of the first lumbar 

 vertebra, and passes to the posterior border of the last rib (this 

 portion is described by the German anatomists as a retractor 

 costce) ; and to the fascia of the latissimus dorsi ; to the cartil- 

 ages of the false ribs ; postero-inferiorly to the symphysis pubis, 

 by the prepubian tendon, aiding in the formation of the internal 

 abdominal ring; inferiorly to the linea alba throughout its whole 

 extent. 



Relation. — Externally with the external oblique ; internally 

 with the transversalis and rectus abdominis. 



Action. — It assists the externus in compressing the abdomen 

 in the act of respiration, and in flexing the spine. It also draws 

 the last rib backwards. 



RECTUS ABDOMINIS. 



(Stertio-jntbialis. ) 



(Pl. III. 18.) 



Situated along the inferior and middle part of the abdomen, it 

 is long, flat, polygastric, and broadest in the middle. Tendinous 

 at its attachments, its belly consists of numerous flat muscular 

 fasciculi, with' transverse tendinous intersections, to which the 

 aponeuroses of the oblique muscles are adherent ; these intersec- 

 tions are called the linece transversa^ {inscriptiones tendinece), 

 and may be regarded as the abdominal representatives of the ribs. 

 The posterior part of the muscle assists in the formation of the 

 internal abdominal ring. 



Attachments. — Anteriorly to the inferior surface of the xiphoid 

 cartilage and sternum ; to the cartilages of the last four true and 

 first two false ribs ; posteriorly to the crest of the pubis, through 

 the medium of the prepubian tendon, which is directly continuous 

 with it ; internally to the linea alba. 



Relations. — Inferiorly with the aponeurosis of the internal 

 oblique muscle ; anteriorly with the pectoralis magnus ; superiorly 

 with the transversalis, and the cartilages of nearly all the ribs ; 

 internally with its fellow at the linea alba. 



