ANATOMY IX A NUTSHELL. 463 



iiig part of the aponeurosis passes horizontally Towards the linea alba, but at 

 the linea semilunaris it passes behind the Rectus muscle blending with the pos- 

 terior layer of the Internal oblique. 



Action. — Same as the External oblique. 



Nerve Supply. — Intercostal, ilio-hypogastric, and sometimes the ilio- 

 inguinal. 



Blood Supply. — Intercostal and lumbar arteries. 



Rectus abdominis. — Description. — This muscle extends from the sym- 

 physis pubes to the sternum. It is much broader and thinner above than 

 below and is separated from its fellow by the linea alba. The linea' transversa 

 are tendinous intersections which cross this muscle. There are three such 

 lines. One is situated opposite the umbilicus and one at the extremity of the 

 ensiform cartilage, and a third one between these two. Occasionally one or 

 two additional lines may be seen. These lines are homologues of ribs. The 

 sheath of the Rectus muscle contains the Pyramidalis muscle and the superior 

 epigastric artery, the deep epigastric artery, anel the terminal branches of the 

 lower intercostal and lumbar arteries anel nerves. 



PLATE CCLI. 



LACHRYMAL 

 GROOVE \/wSjk 



HAMULUS 



The Lachrymal Bone. 



Origin. — By two heads. (1) the external or Larger head being attached to 

 the crest of the os pubes. (2) the internal one is connected with the ligaments 

 covering the symphysis and interlacing with its fellow of the opposite side. 



Insertion. — Into the cartilages of the fifth, sixth, and seventh ribs, and 

 occasionally connected with the costo-ziphoid ligaments and side of the ensi- 

 form cartilage. 



Action. — To compress abdominal viscera, and to flex thorax. 



Xervk Supply. — Lower intercostals. 



Blood Supply. — Intercostal, lumbar, deep epigastric and superior epigas- 

 tric arteries. 



Pyramidalis. — Description. — This muscle is situated in the same sheath 

 with the Rectus abdominis muscle in front of the lower portion of that muscle. 

 It may be absent on one or both sides, or it may be double on one side. 



Origin. — From front of pubic bone and anterior pubic Ligament. 



Insertion. — Into the linea alba half way to the umbilicus. 



Action. — To tense linea alba. 



Nerve Supply. -Twelfth thoracic and ilio-hypogastric. 



