216 '////: MI 94 LS6 



separates tin- skin from the apuucurosis nf the iinul /./*./</.. The mu.>.-nlar {Hirtinn of 

 thi< mn.M-le li:i> no attachnn lit I" the :i|>iiniru.-is nf tin- ,'! at doi.-al. 



Tin- a|M>neurosis of the xiinill <//,//./(/. is divided into two lamelhc ;.t tin- external 



border of we great Btnight maiele; the anterior it oooaolidated with the u'reat oi>ii<|iii'. 



inn! passes in front of the great straight ; the jiosterior i> united to tin- (nm-M TM-, ami 

 - U'hind that muscle. 



TJie ajioucurosis of tlic li-'inKi-i rm- is divided into two leaves, only one of which remains 

 U'hind the great straight muscle,; this is named the fi-niilnniir //// of Itmnjhiit. 



The I/A ii/ /(<///.< inn*-!' <>/ th< alalnim-ii oilers three transverse u'brons inter-ection8 in 

 its length lim.-i tritiiai-i r*;i i ). At its H]I|MT extremity, it divide* into three branches : 

 the internal is attached to the xiphoid appenda-e and the cartilage of the .-event h ril.; 

 the middle, to that of the sixth rib ; the external, to the cartilage of the lifth ri)>. 



"To (he i:ivat rcctus is annexed a small triangular muscle, the i>t/r<tu<i<l<il, whi<-h is 

 not found in animals. This muscle is al>out '2\ inches lun^: is sometime* al^ent : mn.-t 

 developed in children ; is attached by its base to the pubis, iM-twcen the spinf and the 

 .-\ m]ihy>is: and by its summit is continuous with n tendon which is lost in the \\hite 

 line, and constitutes, with that of the opposite bide, a fibrous cord which may be follow. .1 

 to the umbilicus." Jlniiniis (Uid Jloiiclinnl. 



Lastly, at the inner aspect of all the abdominal muscles, beneath the peritoneum, i> 

 a librous lamella the /./ iranKversali*. This fascia is not distinctly limited upwards 

 4r outwards; below, it is tixed to the crural arch, iu the vicinity of the inguinal canal 

 and sends a layer to the surface of the cord spermatic. 



DIAPHHAGMATIC UEGION. 



This is composed of a single muscle, the 



Diaphragm. 



Frejxi ration. Place the subject in the first jiosition ; open the abdomen and IVHMHV 

 the vi.-ceia it contains, as well as the large vascular trunks lying upon the siibluml.ar 

 region; detach the peritoneum from the fleshy portion of the muscle, in order to show 

 the digilations of the latter more distinctly, taking care not to allow the air to cuter the 

 thoracic cavity, as it would destroy the tense and concave form of the diaphragm. 



Situation Direction. The diaphragm is a vast musculo-aponeurotic 

 partition separating the thoracic from the abdominal cavity, between which 

 it is placed in an oblique direction downwards and forwards. 



Form. It is flattened before and behind, elliptical, wider above than 

 below, concave posteriorly, and convex anteriorly. 



Structure. This muscle comprises: 1, A central aponeurotic portion 

 designated the phrenic centre, which is incompletely divided into two folioles 

 (leaflets) by the pillars fleshy columns which descend from the sublumbar 

 region; 2, A peripheral (or circumferential) portion forming a wide 

 muscular band around the phrenic centre. 



The phrenic centre (also named the speculum Hclmontii or mirror of 

 Helmont) is composed of white, glistening, radiating fibres which, originating 

 from the pillars, extend in every direction to join the muscular fibres of the 

 peripheral portion. It is pierced, in its right leaflet, by a large opening for 

 the posterior vena cava. 



The pillars are two ia number, a rifjht and left. The riyld pillar, the 

 most considerable, is a very thick, fleshy fasciculus which commences under 

 the loins by a strong tendon, united to the inferior common vertebral liga- 

 ment. It descends to tho phrenic centre, to which it gives a heart-shaped 

 appearance. Near its inferior extremity, it presents an opening for the pas- 

 sao;<! of the oasophagns into the abdominal cavity. Tho left pillar is a small 

 triangular fasciculus, partly separated from tho preceding by an orifice for 

 tho transmission of the posterior aorta and tho thoracic duct. It also arises 



