Abdominal and Pelvic Anatomy

ABDOMINAL AND PELVIC ANATOMY ANATOMY ANTERIOR ANTERIO R ABDOMINAL WALL: WALL:

The abdomen is divided into regions that are defined by lines on the surface of the anterior abdominal wall o Usua Usuall lly y NINE NINE REGI REGION ONS S are are deli deline neat ated ed by two two vert vertic ical al and and two two horizontal lines o ERTI!"# #INE$ !orres%onds to the &I'!#"I!U#"R #INE on each side when e(tended down to the &I'INGUIN"# )OINT *midway between the %ubic sym%hysis s ym%hysis and the "SIS o +ORI,ONT"# #INES$ #ower transverse line$ 'rawn bet between the tuberc ercles of the iliac crests *INTERTU-ER!U#"R *INTERTU-ER!U#"R #INES. U%%er transverse lines$ In the TR"NS) TR"NS)/#O /#ORI! RI! )#"NE0 )#"NE0 midway midway betwee between n the  1ugular notch and the to%e of the %ubic sym%hysis Using these four lines0 three !ENTR"# REGIONS are defined0 from above downwards$ o E)IG"STRI! o U&-I#I!"# o +/)OG"STRI! Similarly there are T+REE #"TER"# #"TER"# REGIONS on each eac h side$ o +/)O!+ON'R"# #U&-"R  o o I#I"! ANTEROLATERAL ABDOMINAL MUSCLES: The three muscle layers la yers of the body bod y wall are SE)"R"TE SE)"R"TE IN T+E 2#"N3S • o The layers layers have fused fused ventral ventrally ly to form form the RE!TUS RE!TUS "-'O& "-'O&INU INUS S &US!#E EXTERNAL OBLIQUE: • &uscle arises by eight digitations0 one from each of the lower eight ribs o  1ust lateral to their anterior e(tremities e(tremities 2rom its fleshy origin0 it fans out to a very wide insertion0 much of which o is a%oneurotic 2REE )OSTERIOR -OR'ER  o E(tends from the 45th rib to its insertion into the anterior half of the outer li% of I#I"! !REST &uscle fibres are re%laced by an a%oneurosis below a line 1oining the o "SIS to umbilicus 

The a%oneurotic fibres interdigitate with each other across the front of rectus abdominus along the whole length of the linea alba )osterior border of the muscle is free0 and forms the anterior boundary of  o the #U&-"R TRI"NG#E -ounded behind by anterior border of lat dorsi and below by iliac iliac crest o The lower border0 lying between the "SIS and the %ubic tubercle0 forms the INGUIN"# #IG"&ENT Its edge is rolled inwards to form a gutter  #ateral %art of this gutter gives origin to %art of the internal • obli6ue and transversus abdominis muscles 2ascia lata is attached to the inguinal ligament 7ust above and lateral to the %ubic tubercle is an obli6ue0 triangular  ga%0 the SU)ER2I!I"# INGUIN"# RING -ase of the ga% is the %ubic % ubic crest • &argins are the crura of the ring • 2rom the medial end of the inguinal ligament the triangular #"!UN"R  o #IG"&ENT e(tens bac8wards to the %ectineal line and forms the medial margin of the %ectineal line INTERNAL OBLIQUE: 2leshy fibres of the muscle arise from the whole length of the lumbar  o fascia0 from the intermediate area of the anterior tow9thirds of the iliac crest and from the lateral two9thirds of the inguinal ligament 2ibres then run u% along the costal margin *to which they are attached.0 o  becoming a%oneurotic at the ti% of the ninth costal cartilage o +alfway between the umbilicus and the %ubic sym%hysis0 the %osterior  layer ends in a curved free margin0 the "R!U"TE "R!U"TE #INE -elow this %oint0 the a%oneurosis %asses wholly in front of the rectus0 to the linea alba The fibres that arise from the inguinal ligament are continued into an o a%oneurosis that is attached to the crest of the %ubic bone and0 more laterally0 to the %ectineal line This This a%one a%oneur uros osis is is fuse fused d with with a simi simila larr arra arrange ngeme ment nt of the the transversus a%oneurosis to form the !ON7OINT TEN'ON TRANSVERSUS ABDOMINIS: o "rises in continuity from the lateral third of the inguinal ligament0 the anterior two9thirds of the inner li% of the iliac crest0 the lumbar fascia0 45 th rib and from inner as%ects of the lower si( costal cartilages0 where it interdigitates with the dia%hragm 2use with internal obli6ue a%oneurosis behind the rectus in the linea alba o -elow the arcuate line the a%oneurosis %asses wholly in front of the rectus o muscle 

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The a%oneurotic fibres interdigitate with each other across the front of rectus abdominus along the whole length of the linea alba )osterior border of the muscle is free0 and forms the anterior boundary of  o the #U&-"R TRI"NG#E -ounded behind by anterior border of lat dorsi and below by iliac iliac crest o The lower border0 lying between the "SIS and the %ubic tubercle0 forms the INGUIN"# #IG"&ENT Its edge is rolled inwards to form a gutter  #ateral %art of this gutter gives origin to %art of the internal • obli6ue and transversus abdominis muscles 2ascia lata is attached to the inguinal ligament 7ust above and lateral to the %ubic tubercle is an obli6ue0 triangular  ga%0 the SU)ER2I!I"# INGUIN"# RING -ase of the ga% is the %ubic % ubic crest • &argins are the crura of the ring • 2rom the medial end of the inguinal ligament the triangular #"!UN"R  o #IG"&ENT e(tens bac8wards to the %ectineal line and forms the medial margin of the %ectineal line INTERNAL OBLIQUE: 2leshy fibres of the muscle arise from the whole length of the lumbar  o fascia0 from the intermediate area of the anterior tow9thirds of the iliac crest and from the lateral two9thirds of the inguinal ligament 2ibres then run u% along the costal margin *to which they are attached.0 o  becoming a%oneurotic at the ti% of the ninth costal cartilage o +alfway between the umbilicus and the %ubic sym%hysis0 the %osterior  layer ends in a curved free margin0 the "R!U"TE "R!U"TE #INE -elow this %oint0 the a%oneurosis %asses wholly in front of the rectus0 to the linea alba The fibres that arise from the inguinal ligament are continued into an o a%oneurosis that is attached to the crest of the %ubic bone and0 more laterally0 to the %ectineal line This This a%one a%oneur uros osis is is fuse fused d with with a simi simila larr arra arrange ngeme ment nt of the the transversus a%oneurosis to form the !ON7OINT TEN'ON TRANSVERSUS ABDOMINIS: o "rises in continuity from the lateral third of the inguinal ligament0 the anterior two9thirds of the inner li% of the iliac crest0 the lumbar fascia0 45 th rib and from inner as%ects of the lower si( costal cartilages0 where it interdigitates with the dia%hragm 2use with internal obli6ue a%oneurosis behind the rectus in the linea alba o -elow the arcuate line the a%oneurosis %asses wholly in front of the rectus o muscle 

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#ower fibres curve downwards and medially with those of internal obli6ue as the !ON7OINT TEN'ON0 to insert on the %ubic crest and %ectineal line

RECTUS ABDOMINIS AND PYRAMIDALIS: "rises by T:O +E"'S$ • o &edial from in front of the %ubic sym%hysis and a lateral from the u%%er   border  #ateral from the u%%er border of the %ubic crest o o Two muscles lie together in the lower %arts but broaden out above to be se%arated by the #INE" "#-" Inerted on to the front of the ;th9