ANATOMY OF THE LARGE INTESTINE
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Transcript of ANATOMY OF THE LARGE INTESTINE
•ANATOMY OF THE
LARGE INTESTINE
Dr. Ahmed Fathalla IbrahimAssociate Professor of AnatomyCollege of MedicineKing Saud UniversityE-mail: [email protected]
Dr. Jameela Al-MedanyAssociate Professor of AnatomyCollege of MedicineKing Saud University
OBJECTIVESAt the end of the lecture, students should:List the different parts of large intestine.List the characteristic features of colon.Describe the anatomy of different parts of
large intestine regarding: the surface anatomy, peritoneal covering, relations, arterial & nerve supply.
PARTS OF LARGE INTESTINECECUMAPPENDIXASCENDING COLONTRANSVERSE COLONDESCENDING COLONSIGMOID COLON RECTUMANAL CANAL
ABDOMEN
PELVIS
PERINEUM
Abdomen
Pelvis
Perineum
CHARACTERISTICS OF COLON(NOT FOUND IN RECTUM & ANAL CANAL)1. Teniae coli: 3 longitudinal muscle bands2. Sacculations (haustra): teniae coli are
shorter than large intestine3. Epiploic Appendices : short peritoneal fold
filled with fat
PERITONEAL COVERINGPARTS WITH MESENTERY:1. Transverse colon2. Sigmoid colon3. Appendix4. CecumRETROPERITONEAL
PARTS:1. Ascending colon2. Descending colon
PERITONEAL COVERING
RETROPERITONEAL PARTS3. Upper 2/3 of rectumPARTS DEVOID OF
PERITONEAL COVERING:1. Lower 1/3 of rectum2. Anal canal
Rectum
Analcanal
SURFACE ANATOMY
ASIS1/3
2/3McBurney’s point
Right hypochondrium Left hypochondriumEpigastrium
Hypogastrium
Umbilical regionRight lumbar region Left lumbar region
Left iliac fossaRight iliac fossa
APPENDIX Surface anatomy: the base of
appendix is marked by Mc’Burney’s point: A point at the junction of lateral 1/3 & medial 2/3 of a line traced from right anterior superior iliac spine to umbilicus
Opening: at posteromedial aspect of cecum, 1 inch below ileo-cecal junction
Positions:1.Retrocecal: most common 2.Pelvic3.Subcecal4.Preilieal5.Postileal: least common
(5)
(3)
(1)
(4)
(2)
RELATION BETWEEN EMBRYOLOGICAL ORIGIN & NERVE SUPPLY
Origin: Midgut (endoderm)Nerve: Autonomic: Sympathetic + vagus
Origin: Hindgut (endoderm)Nerve: Autonomic: Sympathetic + pelvic splanchnic nerves
Right 2/3Left 1/3
Origin: ectodermNerve: Somatic: inferior rectal
Lower part of anal canal
RELATION BETWEEN EMBRYOLOGICAL ORIGIN OF GUT & ITS ARTERIAL SUPPLY
CECUM – ASCENDING & DESCENDING COLONS (ANTERIOR RELATIONS)
Coils of small intestineGreater omentum
Anterior abdominal wall
CECUM – ASCENDING & DESCENDING COLONS (POSTERIOR RELATIONSCecum:1. Psoas major2. IliacusAscending colon:1. Iliacus2. Quadratus lumborumDescending colon:1. Left kidney2. Quadratus lumborum3. Iliacus4. Psoas major
Quadratus lumborum
RALATIONS OF TRANSVERSE COLONAnterior: greater omentum, anterior abdominal wall Superior: liver, gall bladder, stomach
Inferior: coils of small intestine Posterior: 2nd part of duodenum, pancreas
COLIC FLEXURES
RECTUMBeginning: as a continuation of sigmoid colon at level of S3.Termination: continues as anal canal, one inch below & in front of tip of coccyx. Its end is dilated to form the rectal ampulla.Length: 13 cm(5 inches)
RELATIONS OF RECTUM IN PELVIS
MALE PELVISAnterior: seminal vesicles, posterior surfaces of urinary bladder & prostate glandPosterior: sacrum & coccyx
FEMALE PELVISAnterior: posterior wall of vaginaPosterior: sacrum & coccyx
R R
QUESTION 1
Which one of the following is the most common position of appendix?
1. Subcecal2. Retrocecal3. Pelvic4. Preileal
QUESTION 2
Regarding the transverse colon, which one of the following statements is correct?
1. It is only supplied by the superior mesenteric artery.
2. It has no mesentery.3. It lies behind the pancreas.4. It contains taeniae coli in its wall.
THANK YOU