Pelvis And Perineum

Pelvis
Composition:

• formed by paired hip bones, sacrum, coccyx, and their articulations

Two portions 

• Greater pelvis
• Lesser pelvis
• Terminal line ( pelvic inlet): formed by promontory of sacrum, arcuate line, pectin of pubis, pubic tubercle, upper border of pubic symphysis
• Pelvic outlet: formed by tip of coccyx, sacrotuberous ligament, ischial tuberosity, ramus of ischium, inferior ramus of pubic symphysis

Muscles of pelvic wall

• Piriform m.
• Obturator internus m.

Muscles of floor of pelvis

Levator ani

• Levateo prostate (pubovaginalis)
• Puborectalis
• Pubococcygeus  and iliococcygeus
• Coccygeus

Pelvic  diaphragm

• Superior fascia of pelvic  diaphragm
• Levator ani
• Coccygeus
• Inferior fascia of pelvic  diaphragm

Pelvic fascia 

Parietal pelvic fascia 

• A continuation of the transverse fascia into the pelvis. It coves the piriformis and obturator internus 
• Attaches to the arcuate line of the pubis and ilium, thickens over the obturator internus to form the arcus tendineus, the origin of portions of the levator ani muscle
• At the tendinous arch of levator ani it splits to cove both superior and inferior surfaces of the levator ani as superior and inferior fascia of pelvic diaphragm 

Visceral pelvic fascia 

• Lies between the peritoneum and the pelvic viscera
• It is a continuation of the extra peritoneal connective tissue
• Ensheathes retroperitoneal viscera and forms septa between retroperitoneal organs
• Rectovesical septum        
• Rectovaginal septum         

Retropubic space        

• Lies between pubic symphysis and urinary bladder

Pararectal space 

• Lies around the rectus 

Retrorectal space

Common iliac artery

• Continuation of abdominal aorta at level of L4 vertebra 
• Terminates in front of sacroiliac joint by dividing into internal and external iliac arteries 

Internal iliac artery 

• It is a terminal small branch of the common iliac artery.
• It is about 4 cm long.
• In the foetus, this artery is the origin of the umbilical arteries to the placenta.
• It begins in front of the sacroiliac joint, between L5 and sacrum, medial to psoas muscle, and runs backwards and ends near greater sciatic notch by dividing in to two branches, the anterior and the posterior division.

The relations are:

• Anterior- ureter
• Posterior- internal iliac vein
• Lateral- external iliac vein and the obturator nerve
• Medial- peritoneum and the tributaries of the internal iliac vein.

Anterior division

• Superior vesicle artery
• Obturator artery
• Middle rectal artery
• Inferior vesicle artery
• Inferior gluteal artery
• Internal pudendal artery
• Vaginal artery
• Uterine artery

Posterior division 

• Illiolumbar artery 
• Lateral sacral artery
• Superior gluteal artery

Uterine Artery

• about 2cm from neck of uterus it crosses above and in front of ureter

Internal pudendal artery

• Perineal artery
• Anal  artery
• Dorsal  artery of penis (clitoris) 

Veins of pelvis

Internal iliac vein

• Parietal tributaries: accompany with arteries
• Visceral tributaries
•                  →superior rectal vein→inferior mesenteric v.
• ①Rectal venous plexus    →inferior rectal vein→internal iliac v.
•    →anal vein→internal pudendal v.   
• ②Vesical venous plexus →vesical v.
• ③Uterine venous plexus →uterine v. 
• External iliac– accompany the artery
• Common iliac vein– formed by union of internal and external iliac veins in front of sacroiliac joint, end upon L4~L5 by uniting each other to form inferior vena cava

The lymphatic drainage of pelvis

Internal iliac lymph node

• Surround internal iliac vessels
• Receive afferents from pelvic viscera, perineum, buttock and back of thigh

External iliac lymph nodes 

• Lie along external iliac artery
• Receive afferents from lower limb and some parts of pelvic viscera
• Sacral lymph node

Common iliac lymph node 

• Lie along common iliac artery
• Receive afferents from all the above nodes
• Efferents pass to lumbar lymph node 

Sacral plexus

Formation:

• formed by anterior rami of L4 and L5 spinal nerves (the lumbrosacral trunk) and anterior rami of sacral and coccygeal nerves

Position:

• lies in pelvic cavity, anterior to sacrum and piriformis 

Branches

• Superior gluteal 
• Inferior gluteal 
• Pudendal
• Posterior femoral cutaneou 
• Common Sciatic 
• Autonomic plexuses of plevic
• Hypogastric plexus 

• Superior hypogastric plexus : lies in front of L5 between common iliac ateries
• Inferior hypogastric plexus (pelvic plexus): lie on each side of rectum

Sacral sympathetic trunk

• Is continuos above with the abdominal part
• Has 4or 5 ganglion 

Relationships of rectus

Anteriorly

• In male 
• Fundus of bladder
• Seminal vesicle
• Prostate 
• Ampulla ductus deferentis
• In female 
• neck of uterus
• Vagina 

Posteriorly

• Sacrum and coccyx
• Piriformis
• Median sacral vessels
• Anterior branches of sacral and coccygeal nerves
• Sacral sympathetic trunk

Laterally 

• Pelvic  plexus
• Superior and inferior rectal vessels
• Levator ani  

Vessels and lymphatics of rectum
Arteries 

• Superior rectal a.
• Inferior rectal a.
• Median sacral a.
• Lymphatic drainge Lymphatics follow arterial blood supply to following nodes:
• Superior rectal ln.
• Inferior mesenteric ln. 
• Pararectal ln.
• Internal iliac ln.
• Sacral ln.

Perineum
General features

• Region of below pelvic diaphragm
• A diamond-shape space whose boundaries are those of the pelvic outlet
• Lower border of symphysis pubis
• Rami of pubis and ischium
• Ischial tuberosities
• Sacrotuberous ligament 
• The coccyx

Two triangles
 An imaginary line drawn between the two ischial tuberosities divides perineum into anterior and posterior triangles

• Urogenital region (anterior)－differs in male and female
• It has urogenital diaphram, which is made by,
• Muscles- sphincter urethrae and deep transverse perinei
• Fascia- superficial and deep urogenital fascia 
• Anal region (posterior)－similar in both sexes 

Branches

• Superior gluteal 
• Inferior gluteal 
• Pudendal
• Posterior femoral cutaneou 
• Sciatic Common

Urogenital region 

Superficial fascia has two layers

• The superficial or fatty layer
• The deep or membranous layer (superficial fascia of perineum or Colles fascia) 

 Anteriorly－ it is continuous with:

• Dartos of the scrotum
• Fascia of the penis
• Membranous layer of superficial fascia of the abdominal wall known as the fascia of Scarpa

Deep fascia has two layers

• Superior fascia of urogenital diaphragm
• Inferior fascia of urogenital diaphragm

Superficial perineal pouch 
Boundaries

• Lies between inferior fascia of urogenital diaphragm and superficial fascia of perineum
• Space open anteriorly (In rupture of cavernous part of urethra, urine can extravasate from scrotum upward in front of symphysis pubis into anterior abdominal wall deep to membranous fascia of Scarpa)

Contents

• Posterior part－superficial transverse perineal muscle
• Lateral part－crus penis (male), crus of clitoris (female) and ischiocavernousus covering them
• Central part－bulb of urethra (male), bulb of vestibule (female) and bulbocavernousus covering them
• Branches of pudendal nerves and internal pudendal vessels

Deep perineal space

Lies between superior and inferior fascia of urogenital diaphragm
Contents 

• Deep transverse perineal muscle
• Bulbourethral gland (male)
• Sphincter of urethra (male)，urethrovaginal sphincter
• Ateries, veins and nerves

Urogenital diaphragm 

Triangular in shape
Attached laterally to ischiopubic rami and ischial tuberosities

Formed by sphincter of urethra, deep transverse perineal muscle, superior and inferior fascia of urogenital diaphragm

perineal body

• Wedge-shape fibromuscular mass
• In female, between anal canal and lower end of vagina, 
• In male, between anal canal and root of penis
• It is larger in the female than in the male and five support to the posterior wall of the vagina

Origin or insertion of several small muscles and insertion of part of palvic diaphragm

These  muscles are: 

• Sphincter ani externus 
• Levator ani 
• Superficial transverse muscle perineum 
• Deep transverse muscles perineum 
• Bulbocavernousus  
• Sphincter of urethra (male) or urethrovaginal sphincter (female)

Pelvic organs

• Male reproductive organs
• Female reproductive organs
• GI organs like rectum and anal canal
• Urinary system organs like distal ureter, bladder and the urethra.

 Urinary structures 
Ureter:

• They are narrow paired tubes that convey the urine to the bladder.
• 25 cm long and 3mm in diameter.
• Upper half is in the abdomen and the lower half in the pelvis.

Course:

• Begins from the renal pelvis.
• Passes downwards and slightly medial to the psoas muscle.
• Crosses the external iliac artery near its origin from the common iliac artery to reach the pelvis.
• Runs along the greater sciatic notch, medially and posterior.
• Then comes anterior and medially to reach the base of the bladder. 

Constrictions:

• At pelviureteral junction
• At when it passes into the pelvis, crossing the internal iliac artery
• At its insertion into the bladder, called as vesicoureteral junction.

Blood supply:

• Upper part- renal artery
• Middle part- branches of the aorta
• Inferior part- branches from the vesicular, middle rectal and uterine vessels.

Nerve-

• smpathetic and parasympathetic from the T10-L1 and S2-4 respectively.

It has an important relation with the uterine artery in its forward course, it passes beneath the uterine artery in the extraperitoneal sheath between the medial and the lower part of the broad ligament. Here it can be ligated or cut during the hysterectomy.

Urinary bladder 

• It is the site of temporary storage of urine.
• The size, location and shape depends on the amount of the urine that the bladder contains.
• It is in the pelvis when empty, but comes to the abdomen when its full.

When empty, it is pear shaped with the following parts:

• Apex forward
• Base backwards
• Neck below attached with the urethra and
• Three surfaces- superior, right and left inferolateral

Relations:

• Anterior: apex is connected to the umbilical by median umbilical ligament (degenerated urachus).

Base/posterior- 

• cervix and vagina in females
• males- rectum superiorly by rectovesical pouch, and inferiorly fascia of denonvillers with the seminal vesicles and the vas deferens.

Neck-

• Males- related to the prostate gland.
• Female- it lies in the pelvic fascia.

Superior-

• its covered by the peritoneum.

Urethra
It is the organ for the external drainage of the urine.
It has dual function in males:

• Ejaculation
• Urine voiding.
• But is has only the urinary function in the female.
• The length is 15-20 cm in the males, and it is only 4 cm in females.
• Blood is supplied by the branches from the prostatic vessels and the penile vessels.

Parts:

• Prostatic part (3cm)- beneath the prostate gland
• Membranous part(2cm)- inside the pelvic diaphragm
• Spongy or penile part(15 cm)- inside the corpus spongiosum in the penis, ventral surface.
• The prostatic urethra is only the homologus part of the female urethra.

The opening of the urethra is guarded by two sets of sphincters:

Internal sphincters

• they are just the condensation of the muscles of the bladder in circular fashion around the neck of the bladder.
• They are supplied by the autonomic fibers.
• They are functional in man, and less in woman.
• Their function is the control of the retrograde ejaculation, no the urine continence.

External sphincter:

• Located in the urogenital diaphragm.
• Has circular muscles, called as sphincter urethrae.
• It is supplied by pudendal nerve.
• It is under voluntary control.
• They are developed in both males and the females.
• Function is the urinary continence. 

Lymphatic drainage: 

• from the prostatic and membranous part is to the internal iliac nodes, and
•  from the penile part is to the deep inguinal nodes.

Rectum

• It lies between the sigmoid colon and the anal canal.
• When it is full, person will have urge to defecate.

Location:

• In the true pelvis, in front of the S3-S5.
• Length is 12 cm and is 4 cm wide.

It has two curves:

• anteroposterior- first anterior, then posterior.
• Lateral- first convex to right, then left and then again right.

Relations
Peritoneum:

• Upper third- covered by peritoneum from the sides and the front
• Middle 3rd- only front
• Distal 3rd- no peritoneum.

Anterior:

• Males- rectovesical pouch with intestines, urinary bladder, seminal vesicle and prostate from up to down.
• Females- rectouterine pouch, cervix and vagina.

Posterior:

• Sacrum
• Pyriformis
• Sacral vessels
• Sympathetic chain and nerves.

It has three prominent mucosal folds, called as the valve of Heuston, the function of these valves is not clear.

They are also called as plica transversalis.

Blood supply:

• Superior rectal artery- (main artery) branch of the inferior mesenteric artery
• Middle rectal – branch of the internal illiac
• inferior rectal artery- branch of internal pudendal artery.
• Median sacral- arises from the back of aorta.

Venous drainage

• Superior rectal vein- goes to Inf. Mes. Vein (portal)
• Middle and Inferior rectal vein- to internal iliac vein (systemic)

Lymphatics

• Superior half- to the inferior mesenteric nodes
• Inferior half- internal iliac nodes.

Anal region

Anal sphincters
Internal 

• Smooth muscle (thickened circular muscle coat)
• Surrounds upper two-thirds of anal canal
• Autonomic nerve supply

External 

• Striated muscle
• Surrounds lower two-thirds of anal canal
• Three parts－subcutaneous, superficial and deep
• Innervation by anal nerves of pudendal nerve and branches of S4

Inner surface:

• Inner surface is divided into upper  15 mm and below 25 mm by a line called as pectinate line.
• The upper part is developed from the anorectal membrane (part of cloaca, and the inferior is from the invagination of the ectoderm).
• The upper part has mucosal folds called as the folds of Morgagni.

Sphincters-

• There are two sets of sphincters,
• External sphincters
• Internal sphincters.
• The internal sphincters are made of the condensed circular muscles of the wall of the anal canal, that covers the proximal 2 cm of the length of the wall of the anal canal. It is involuntary.
• The external sphincter is striated, and is voluntary. It covers all the length of the anal canal. It has three parts, sub-cutaneus, superficial and deep parts. 

Blood supply:

• Arterial supply
• Above the pectinate line- sup. Rectal artery
• Below the pectinate line- inf rectal artery

Venous drainage:

• Superficial and deep venous plexus, that drains into superior and inferior rectal veins respectively. There is free communication between these two channels, and is a site of portocaval shunt.
• The internal venous plexus has the beginning of major veins in 3, 7 and 11 o’clock, the hemorrhoidal veins.
• Enlarged veins due to straining, tumors, or increased portal pressure is called varices, which can cause significant bleeding during defecation.

Lymphatics:

• Above pectinate line- to internal iliac nodes
• Below the pectinate line- to superficial inguinal nodes.

Nerve supply:

• Above pectinate line- autonomic nervous system
• Below pectinate line- somatic nerve, inferior rectal nerve (S2-S4)

Ischiorectal fossa

Paired, wedge-shaped, fat-filled spaces on either side of anal canal

Boundaries

• Apex－conjunctive area of inferior fascia of pelvic diaphragm and fascia covering the obturator internus
• Base－skin of anal region
• Medial－sphincter ani externus, levator ani, coccygeus and inferior fascia of pelvic diaphragm
• Lateral－ischial tuberosity, obturator internus and fascia

Contents

• Fat
• Internal pudendal artery and vein and their rectal branches
• Pudendal nerve and its inferior rectal branch

Vessels and nerves enter from gluteal region, through lesser sciatic 

foramen, travel on a fascial canal－the pudental canal (Alcock’s)

－on the lateral wall of fossa, and extend forward into urogenital region

Female reproductive organs 

• Ovaries
• Fallopian tubes
• Uterus
• Vagina
• Vulva

Ovaries

• They are the female gonads.
• They lie on the fossa on the lateral pelvic wall, that is called as ovarian fossa.

The boundaries of the ovarian fossa are:

• Anterior- oblitrrated umbilical artery
• Posterior- ureter and internal iliac artery

relations:

• It is entirely covered with the peritoneum.
• It is connected to the posterior layer of the broad ligament by folds of the peritoneum, called as mesovarium, which contains the ovarian artery. 
• The lateral part of the broad ligament that transmit the vessels of the ovary is called as the infundibulopelvic ligament.
• Development- from the gonadal ridge on th eposterior abdominal wall.

Histology:

• Cortex with the supporting and germ cells at different stages of development
• Medulla with the ground tissue, blood vessels and the lymphatics

Blood supply:

• Ovarian artery- branch of the abdominal aorta
• Vein- ovarian vein, right to IVC and left to renal vein.

Nerves-

• Sympathetic and parasympathetic nerves.

Uterine tubes:

• Development- from the paramesonephric  (Mullerian) ducts.
• Also calles as fallopian tubes.
• 10 cm long.

Location:

• Free upper margin of the broad ligament.

Parts:

• Interstitial part- inside the wall of the myometrium
• Isthmus- narrow constricted part between the interstitial and the ampulla.
• Ampulla- dilated distal 2/3rd part
• Infundibulum with fimbria.

Blood supply- 

• Medial 2/3rd by uterine artery
• Lateral 1/3rd by ovarian artery.

Lymphatics:

• Isthmus- to superficial inguinal nodes
• Rest all to aortic and preaortic lymph nodes.

Uterus

• It is called as womb.
• It lies in the true pelvis between the urinary bladder and the rectum.
• Pyriform in shape.

Position:

• Anteversion- the axis of the cervix makes an angle of the 90 deg with the long axis of the vagina, called as anteversion.
• Anteflexion- the long axis of the uterus makes an angle of 120 deg with the long axis of the cervix is called asteflexion.
• So the uterus lies anterior and superior to the vagina.
• If the uterus is lying posterior to the axis of the vagina, that’s called retroversion, that may predispose to miscarriage and uterine prolapse.

Supports of the uterus:

• The structure that provide stability to the uterus and prevent uterine descent.

They are:
Primary support:

• Pelvic diaphragm
• Urogenital diaphragm
• Perineal body.

Mechanical support:

• Uterine axis
• Pubocervical ligament
• Tranverse cervical ligament of Mackenrodt’s
• Uterosacral ligament
• Round ligaments of the uterus

Secondary supports:

• Broad ligaments
• Uterovesical fold of peritoneum
• Rectovaginal fold of peritoneus.
• Disruption of one or more of the herementioned structures, will cause uterine descent, called as the uterine prolapse.

Histology:

• Endometrium
• Myometrium
• Perimetrium

Parts:

• Cervix
• Body
• Fundus- posterior wall of the fundus is the commonest site of the implantation.

Vagina:

• Muscular organ

Walls:

• Anterior 6 cm
• Posterior 8 cm

Fornices

• Anterior
• posterior 
• Lateral
• Mucosa- stratified squamos
• Blood- vaginal artery
• Lymphatics- internal iliac nodes

Nerve:

• Lower 3rd- pain sensitive and hence by pudendal nerve
• Upper 2/3rd by autonomic and hence are pain insensitive.

Regional anatomy of abdomen

Esophagus

• Extends from hypopharynx to the stomach.
• Pierces diaphragm at T10 level.
• It has the following layers:
• outer  adventitious layer
• Muscular layer containing outer longitudional and inner circular layer
• Submucus layer
• Mucosa.
• It is 25 cm long.

It has three constrictions,

• at the starting point of esophagus by cricopharyngeus muscle
• at the point of crossing by the bronchus
• at the lower side when the esophagus enters the stomach. Where it is called as lower esophageal junction.
• Incompetence at the LES leads to reflux disease.
• If the LES is not relaxed, it causes achalasia cardia.
• The blood supply is by the esophageal arteries. Branch of the thoracic aorta.

Stomach 

Stomach 25 cm long organ that lies in the left hypochondrium, and the epigastric region.
It has the following parts:

• Cardia
• Fundus
• Body
• Pylorus.
• Fundus has gland called as fundal gland, that has three types of cells,
• Chief or peptic cells: that produce pepsinogen
• Oxyntic cells: that produce HCl and intrinsic factor
• Goblet cells: that produces mucus.
• Pylorus has pyloric gland, that has G cells, which produce gastrin.
• Gastrin stimulates production of HCl.

• The inner mucosa of stomach is folded in itself to form the gastric rugae, that increases the surface area.
• It has the greater curvature and the lesser curvature.

Layers of stomach:

• Mucosa
• Muscularis mucosa
• Submucosa
• Muscularis layer: three layers of muscles.
• Serosa.

Functions of stomach

• storage of large quantities of food until the food can be processed in the stomach, duodenum, and lower intestinal tract; 
• mixing of this food with gastric secretions until it forms a semi fluid mixture called chyme; and 
• slow emptying of the chyme from the stomach into the small intestine at a rate suitable for proper digestion and absorption by the small intestine.
• Start of digestion of carbohydrate and protein.
• Acidic environment of the stomach helps kill pathogens of the food.
• Acidity helps better degradation of food materials.
• Gastric acid helps conversion of the pepsinogen into pepsin, which digests protein.

Blood supply:

• Gastric artery, the branch of hepatic artery, and gastroepiploic arteries of the spleenic artery, and the gastroduedenal artery.
• Veins corresponds with the arteries.

Lymphatic drainage:

• Gastric, hepatic and splenic nodes.

Nerve supply: 

• from the vagus nerve.
• Myenteric and meissner’s plexus.

Small intestine

It has the following parts:
Duodenum
Jejunum and
Ileum.
It is about 5 mt. long, from the pylorus to the ileocaecal junction.
It is the site of maximum absorption.
The mucosa of the intestine has villi, which are the folding of mucus membrane, that increases the absorption surface area.
They are suspended from the posterior body wall by mesentery.

Duodenum

• It is C shaped and 25 cm long.
• It begins from pylorus and joins to the jejunum.
• It has 4 parts, and all except the first part are the retroperitoneal structures.
• The second part has the opening of the CBD and pancreatic duct.
• The distal part of the CBD is dilated, which is called as the ampulla of Vater.
• The opening is guarded by a valve called sphincter of Oddi.
• The submucosa has the mucus glands (Brunner’s gland).
• It is the commonest site for the duodenal ulcer.
• Duodenal ulcer……..something!!
• Blood supply: gastroduedenal artery.

Parts:

• 1st part- 2.5 cm long, continuous with the pylorus, intraperitoneal part.
• 2nd part- 7.5 cm vertical descending part with the opening of the CBD, retroperitoneal.
• 3rd part- 10 cm horizontal part, retroperitoneal.
• 4th part- distal small ascending part 2.5 cm, retroperitoneal.

Jejunum and ileum

• Jejunum is 2 m long and the ileum 3m.
• jejunum is the place of maximum absorption.
• It is rich in villi.
• The cells of the jejunal mucosa has the brush like boarders, that increases the surface area.
• Blood supply: from the jejunal and ileal arteries which are the branches of the superior mesenteric arteries.
• The ileum has numerous lymphoid follicles in the submucosa, called payer’s patch, which get inflamed and ulcerated in the typhoid fever.
• Ileum is mainly concerned with the absorption of the water.
• The ileum is joined to the caecum of the colon at ileocaeal junction which is guarded by the ileocaecal valve.
• The caecum has a blind structure called as the vermiform appendix.
• Appendix is normally rudimentary in man, and it sometimes get inflamed causing appendicitis.
• The ileocaecal valve causes slow releases of the food contents into the colon.
• Lymphatic drainage: to the superior mesenteric lymph nodes.

Appendix

• In the right illiac fossa of the abdomen, attached to the caecum.
• 8-10 cm long and the lumen is 5 mm in diameter.
• Rudimentary organs in human beings.
• Secondary Retroperitoneal organ.
• Mc Burney’s point

location

• Retro-cecal
• pelvic
• Pre-ileal
• Post-ileal. 
• Blood supply: appendicular branch of illecolic artery

Positions or Locations Of Appendix

Colon

• It is also called as the large bowel or large intestine.

It has the following parts:

• Caecum
• Ascending colon (20 cm)
• Hepatic flexure
• Transverse colon (45 cm)
• Spleenic flexure
• Descending colon (30 cm)
• Sigmoid colon (35 cm)
• Rectum (12 cm)
• Anal canal (4cm)
• Taenia coli
• haustrations

Portal Circulation

Liver (Portal Triads)

Gall bladder

• Lies in the inferior surface of liver in gall bladder fossa.
• It stores and concentrates bile.
• Dimension- 7-10 X 3 cm
• Capacity- 60 ml

Parts:

• Fundus
• Body
• Neck with hartman’s pouch

Cystic duct and CBD

• It is 4 cm duct.
• It drains into the common bile duct. 
• The mucosa of the cystic duct forms 15-20 spiral folding, they are called valves of Heuster.
• CBD is 7-8 cm long and is 6 mm in diameter.
• It begins in the inferior surface of the liver by union of two hepatic ducts.
• When the cystic duct mixes with the hepatic duct, its called as CBD.
• It drains into the 2nd part of duodenum with the pancreatic duct.
• Before the opening, the distal part of this duct is dilated, that is called as the ampulla of vator, and it has a valve, called as the sphincter of ODDI.

Pancreas:

• Pan- all, creas- flesh.
• Size- 15-20 cm x 3 cm
• Lies transversly in the abdomen, between the duodenum and the spleen.
• Seperated from the stomach by lesser sac.
• It has head, uncinate process, neck, body and tail.
• The head is related with the duodenum, lies in the vicinity of the duodenum and hence its called as the romance of abdomen.
• It has two ducts- that drains the pancreatic fluid in the duodenum
• Duct of Wirsung /major duct- it drains the neck, body and tail, 3mm in diameter and drains into the CBD.
• Duct of Santorini- drains the head and the uncinate process, and open in the duodenum as separate opening.

Parts:

• Head
• Uncinate process
• Body and
• Tail.

Blood supply

• Head and uncinate process- by the superior and inferior pancreaticoduodenal artery.
• The body and tail by the branches of the splenic artery.

Function

• Exocrine function
• Endocrine function

Histology: 

• Acini
• Pancreatic islets (islets of langerhans)

Omentum

• The folds of peritoneum between the stomach and other visceral organs.
• It covers the coils of the intestine.

They are two,

• Greater omentum
• Lesser omentum.

Greater omentum:

• It is called as the policeman of the abdomen.
• Between the stomach and the tranverse colon.
• Has four folds of peritoneum.
• The space between the 2nd and the 3rd layer makes a sac called as lesser sac behind the stomach and the pancreas, also called as the omental bursa.

Contents:

• Right and the left gastroepiploic vessels
• Fat.

Lesser omentum:

• It is the fold of peritoneum between the lesser curvature of the stomach  and the 1st part of the duodenum to the liver.

It is divided into

• Hepatogastric ligament
• Hepatoduodenal ligament

Contents:

• Hepatic artery
• Portal vein
• Bile duct
• Lymphatics
• Right and the left gastric vessels.

Mesentery

• The fold of the peritoneum that suspends the coils of intestines with the posterior body wall.
• It is fan shaped, with small root.
• The root is 15 cm and attached to the posterior body wall that runs obliquely from the left of the L2 vertebra, to the right sacroiliac joint.
• The intestinal boarder is around 6 m long.

Contents:

• Jejunal and ileal branches of the SMA
• Veins
• Nerves
• Lacteals and lymphatics
• Fat
• Transverse mesocolon, mesoappendix and sigmoid mesocolons are similar folds of the peritoneum that suspends the transverse colon, appendix and the sigmoid colon

Relations of the stomach

Anteriorly:

• Liver (right part) 
• Diaphragm (left upper part) 
• Anterior abdominal wall (left lower part) 

Posteriorly separated by peritoneum of lesser sac from the following (“stomach-bed”) 

• Pancreas 
• Left suprarenal gland
• Left kidney
• Spleen 
• Transverse colon and transverse mesocolon

Arteries of stomach

Left and right gastric arteries 

• Arise from celiac trunk and proper hepatic artery, respectively. 
• These two vessels run in lesser omentum along lesser curvature , and anastomose end-to-end.

Right and left gastroepiploic arteries 

• Arise from the gastroduodenal and splenic  artery, respectively. 
• These two vessels pass into the greater omentum, run parallel to the greater curvature, and anastomose end-to-end.

Short gastric arteries 

• Branches of splenic artery 
• Course through the gastrosplenic ligament
• Supply the fundus of stomach. 

Posterior gastric artery (72%) 

• Arise from the splenic artery 
• Course through the gastrophrenic ligament and supply the posterior wall of fundus of stomach.

• Right and left gastric veins empty directly into hepatic portal vein.
• Left gastroepiploic and short gastric veins drain into hepatic portal vein via the splenic vein.
• Right gastroepiploic vein  drain into superior mesenteric vein.

Lymph drainage of stomach

• Right and left gastric ln. lie along the same vessels and finally to the celiac ln.
• Right and left gastroomental ln. lie along the same vessels, the former drain into subpyloric ln., the latter drain into splenic ln.
• Suprapyloric and subpyloric ln. receive lymphatics from pyloric part and  finally to the celiac ln.
• Splenic ln. receive lymphatics from fundus and left third of stomach, and finally to the celiac ln.  

Parasympathetic innervation 

• The anterior vagal trunk divides into anterior gastric and hepatic branches
• The posterior vagal trunk divides into posterior gastric and celiac branches
• The anterior and posterior gastric branches descend on the anterior and posterior surfaces of the stomach as a rule about 1 to 2 cm from the lesser curvature and parallel to it in the lesser omentum as far as the pyloric antrum to fan out into branches called “crow’s foot” to supply the pyloric part

Sympathetic innervation

• Mainly from celiac ganglia
• Afferent and efferent fibers derives from thoracic segments (T5 －L1)

Relations of duodenum

Relations of  superior part (1st part)  
Anteriorly

• Quadrate lobe of live
• Gallbladder

Posteriorly

• Common bile duct 
• Gastroduodenal a.
• Hepatic portal v.
• Inferior vena cava

Superioely 

• Omental foramen

Inferiorly 

• Head of pancreas 

Relations of  descending part (2nd) 

Anteriorly

• Liver
• Transverse colon and transverse mesocolon
• Loops of small intestine 

Posteriorly 

• Right renal hilum and ureter
• Right renal vessels

Medially

• Head of pancreas
• Common bile duct and pancreatic duct

Laterally 

• Right colic flexure

Relations of horizontal part (3rd) 

Superiorly

• Head of pancreas

Inferiorly 

• Loops of small intestine 

Anteriorly

• Radix of mesentery
• Superior mesenteric a. and v. 

Posteriorly

• Right ureter
• Inferior vena cava
• Abdominal aorta 

Relations of ascending part (4th)

• Right — Head of pancreas and abdominal aorta
• Left — left kidney and ureter
• Arteries Superior pancreaticoduodenal a. (branch of hepatic artery….coeliac trunk)
• Inferior pancreaticoduodenal a. (branch of superior mesenteric artery)
• Spleenic artery.
• Veins follow arteries, draining directly into superior mesenteric and hepatic portal veins 

Relations of liver

Diaphragmatic surface          
separated by diaphragm from the following
Right costodiaphramatic recess and lung
Cardiac base
Visceral surface
Left lobe is related to the stomach and abdominal part of esophagus

Right lobe is related to the right colic flexure anterioly, gallbladder and superior duodenal flexure medially, right kidney, superarenal gland posteriorly

Divisions and relations of common bile duct

Divisions 
Supraduodenal segment
Retroduodenal segment
Pancreatic segment
Intraduodenal segment

Relations of common bile duct
Supraduodenal segment 

• Descends along the right margin of hepatoduodenal lig.
• To the right of proper hepatic a.
• Anterior to hepatic portal v.

Retroduodenal segment 

• Behind the superior part of duodenum
• Anterior to the vena cava
• To the right of the hepatic portal v.

Pancreatic segment

• Lies in a groove between posterior surface of  head of pancreas and duodenum 

Intraduodenal segment 

• Enters the wall of descending part of  duodenum obliquely where jions the pancreatic duct to form the hepatopancreatic ampulla 
• Opens at the major duodenal papilla

Cystohepatic triangle (Calot’s Triangle)
Boundaries

• Common hepatic duct on the left 
• Cystic  duct on the right
• Liver superiorly

Content: cystic artery, lymphatics and fat.

The Pancreas

 Four parts

• Head -Lies within the cancavity of the C-shaped curvatune of duodenum
• Uncinate process－ a projection to the left from the lower part of the head behind the superior mesenteric vessels.
• Neck－narrow part, overlies the superior mesenteric vessels and beginning of the portal vein
• Body－triangular in cross section, passes upward and to the left across the midline
• Tail－extends to the hilum of spleen in the splenorenal ligament

Relations of pancreas

Head of pancreas

• Located in C-shapes curvature of doudenum

Anteriorly 

• Transverse mesocolon 

Posteriorly 

• Inferior vena cava
• Right renal vessels
• Common bile duct 

Neck of pancreas 

• Anteriorly－pylorus
• Posteriorly－beginning of hepatic portal v. 

Body of pancreas

Anteriorly 

• Separated from stomach by omental bursa

Posteriorly

• Abdominal aorta
• Left suprarenal gland
• Left kidney
• Left renal vessels
• Spleen vein

Superiorly 

• Celiac trunk 
• Celiac plexus
• Splenic a.

Relations of spleen

Diaphragmatic surface－diaphragm
Visceral surface
Anteriorly－fundus of stomach
Posteriorly－left suprarenal gland and kidney

Inferiorly－tail of pancreas and left colic flexure

Retroperitoneal space

Position－it lies between the parietal peritoneum and transvers fascia of the posterior abdominal wall, from diaphragm to promontory of sacrum, continuation with extraperitoneal fascia.
Contents

• Kidney
• Suprarenal gland
• Ureter
• Abdominal aorta
• Inferior vena cava
• Nerves and lymphatics
• Loose connective tissue

Kidney

• Paired structures in the retroperitoneum.
• Size 11x6x3 cm.
• The right kidney is slightly lower than the right kidney due to relative position of the liver.
• The kidney lie in the lumbar region, but it occupies some space in the hypochondrium, and umbilical regions.
• Each kidney has two parts, the medulla and the cortex.
• Microscopically, each kidney has its functional units that are called as nephrons.

Relations of the kidney 

Right kidney
Anterior-

• liver,
• 2nd part of diaphragm,
• hepatic flexure and small intestines.

Superior;

• Adrenal gland

Medial:

• Ureter

Posterior:

• Diaphragm
• Muscles- psoas, quadratus lumborum, tranversus abdominis.
• Subcoastal illiohypogastric and illioinguinal nerves
• Rib 12th.

Left kidney
Antrior:

• Adrenal
• Spleen
• Stomach
• Pancreas
• Spleenic flexure
• Jejunum 

Superior;

• Adrenal gland

Medial:

• Ureter

Posterior:

• Diaphragm
• Muscles- psoas, quadratus lumborum, tranversus abdominis.
• Subcoastal illiohypogastric and illioinguinal nerves
• Ribs 11th and 12th.

Covering of kidney (from inner to outer)

• Fibrous capsule
• Perirenal fat
• Gerota’s fascia.

Blood supply:

• Artery- renal artery, 30 % will have accessory renal artery.
• Vein- renal vein
• Lymphatic drainage 
• To paraaortic lymph nodes.

Suprarenal gland
Shape and position

• Right is pyramidal in shape, left one semilunar in shape, consisting of out cortex and inner medulla
• Located retroperitoneally, superomedial to superior poles of each kidney, enclose with the kidney by the renal fascia

Blood supply
Arteries

• Superior suprarenal a.
• Middle suprarenal a.
• Inferior suprarenal a.

Venous drain

• Right suprarenal v. drains into inferior vena cava
• Left suprarenal v. joins left renal v.