Radiographic Anatomy

Digestive System

Educational Objectives

By the end of this lecture you should be able to:• Identify the anatomical parts of the digestive system on

diagrams and radiographs.

• Identify the relations between the different parts of the GIT

• Explain how to hang GIT radiographs on the view box

• State and locate the surface land marks associated with the abdomen.

4

1. Text book of radiographic positioning and related anatomy; by Kenneth L.Bontrager,6th edition. 2. Introduction to Human Anatomy and Physiology: by Eldra Pearl Solomon:W.B.Saunders Company 3. Handbook of Anatomy and physiology for Students of Medical Radiation Technology: Mallett.M:Jaspar

Websiteshttp://www6.district125.k12.il.us/science/anatomy/http://www.innerbody.com/htm/body.html http://www.e-radiography.net/

http://www.getbodysmart.com/index.htm

References

Digestive System

(gastrointestinal; GI tract)– Stomach

A. Fundus (fluid level seen in erect

position)A. BodyB. Pyloric Antrum

– Small intestines (small bowel)

A. Duodenum ("c" shape; bulb)

B. jejunum

C. ileum

Large intestine (colon)A. Caecum (valve; appendix)

B. Ascending colon

C. Hepatic flexure

D. Transverse colon

E. Splenic flexure

F. Descending colon

G. Sigmoid colon (flexure)

H. Rectum and anal canal

Accessory GI tract organsA. Salivary glands

B. Liver &Gall bladder

C. Pancreas

Digestive System

(gastrointestinal; GI tract)

• Abdomen divisions

4 Quadrants )clinically( 9 Regions (anatomically)

Quadrants & Regions of the abdomen

Quadrants & Regions of the abdomen

MSP: mid-sagittal planeMSP: mid-sagittal planeTUP: transumblical plane (L4/5)TUP: transumblical plane (L4/5)

RLL: right lateral planeRLL: right lateral planeLLL : left lateral planeLLL : left lateral planeTPP: transpyloric plane (L 1)TPP: transpyloric plane (L 1)TTP: transtubercular plane (L 5)TTP: transtubercular plane (L 5)

Regions of the abdomen

Digestive SystemDigestive System

)I(: Alimentary canal:)I(: Alimentary canal:– 9 m length 9 m length – Extend from mouth to anusExtend from mouth to anus

►►Oral cavityOral cavity►►PharynxPharynx►►EsophagusEsophagus►►StomachStomach►►Intestine (small & large)Intestine (small & large)

)II(: Accessory organs:)II(: Accessory organs:– Salivary glandsSalivary glands– PancreasPancreas– Liver and biliary systemLiver and biliary system

PharynxPharynx

◙◙ 3 parts:3 parts:

)I(: Nasopharynx:)I(: Nasopharynx:• Skull base to the level of soft palate Skull base to the level of soft palate • Anterior: nasal cavity (posterior nares)Anterior: nasal cavity (posterior nares)• Inferior: nasopharyngeal isthmus Inferior: nasopharyngeal isthmus • Lateral wall: opening of auditory tubeLateral wall: opening of auditory tube• Roof: adenoidRoof: adenoid

◙◙ Levels : Levels : from skull base to level of C-6 (13 cm). from skull base to level of C-6 (13 cm).

)II(: Oropharynx:)II(: Oropharynx:• Level of soft palate to tip of epiglottisLevel of soft palate to tip of epiglottis• Anterior: oropharyngeal isthmus Anterior: oropharyngeal isthmus

)III(: Laryngopharynx:)III(: Laryngopharynx:• Tip of epiglottis to level of C-6Tip of epiglottis to level of C-6• Pyriform fossa Pyriform fossa

EsophagusEsophagus

◙◙ Relations: )3 areas(Relations: )3 areas(

)I(: In the neck:)I(: In the neck:• Anterior: trachea, thyroidAnterior: trachea, thyroid• Posterior: cervical vertebraePosterior: cervical vertebrae• Lateral: common carotid arteryLateral: common carotid artery

◙◙ Levels : Levels : from C-6 to T-11 (25 cm).from C-6 to T-11 (25 cm).Normal points of narrownessNormal points of narrowness: (1) Level of cricoid cartilage; (2) Level of left main bronchus;(3) : (1) Level of cricoid cartilage; (2) Level of left main bronchus;(3)

Passing through the diaphragm. Venous drainage of the lower oesophagus form a point of Passing through the diaphragm. Venous drainage of the lower oesophagus form a point of communication between portal and systemic veins; any obstruction of the portal venous system communication between portal and systemic veins; any obstruction of the portal venous system

may lead may lead to oseophageal varicesto oseophageal varices..

)II(: In the thorax:)II(: In the thorax:• Anterior: trachea, Lt. main bronchus, Lt. atriumAnterior: trachea, Lt. main bronchus, Lt. atrium• Posterior: thoracic vertebrae, thoracic duct, descending aortaPosterior: thoracic vertebrae, thoracic duct, descending aorta• Lateral:Lateral:

– Right side: azygous vein, right lungRight side: azygous vein, right lung– Left side: Left side:

• Superior med.: Lt. subclavian artery, aortic arch, Lt. lungSuperior med.: Lt. subclavian artery, aortic arch, Lt. lung• Inferior med.: descending aorta, Lt. lungInferior med.: descending aorta, Lt. lung)III(: In the abdomen: 1-3 cm ; the phrenic ampulla lies just above the )III(: In the abdomen: 1-3 cm ; the phrenic ampulla lies just above the

cardia and may simulate hiatus hernia. The abdominal part is called cardia and may simulate hiatus hernia. The abdominal part is called )submerged segment( and help to prevent reflux from the stomach. )submerged segment( and help to prevent reflux from the stomach. Other factors: Acute gastro-oesophageal angle,pressure of right crus Other factors: Acute gastro-oesophageal angle,pressure of right crus of the diaphragm and intrinsic muscles sphincter. of the diaphragm and intrinsic muscles sphincter.

StomachStomach

◙◙ Shape: Shape: J-shaped, but may varies (volume, position, resp., build) J-shaped, but may varies (volume, position, resp., build)

◙◙ 2 Orifices: 2 Orifices: 1.1. CardiacCardiac2.2. Pyloric Pyloric

◙◙ 2 Curvatures:2 Curvatures:1.1. LesserLesser2.2. GreaterGreater

◙◙ 3 Parts: 3 Parts: 1.1. Fundus (air bubble)Fundus (air bubble)2.2. BodyBody3.3. Antrum Antrum

◙◙ Mucosa: gastric rugaeMucosa: gastric rugae - - Longitudinal: on lesser curvatureLongitudinal: on lesser curvature - Random (mosaic): elsewhere- Random (mosaic): elsewhere

◙◙ Muscles:Muscles:1.1. Outer: longitudinalOuter: longitudinal2.2. Inner: circularInner: circular3.3. Innermost: obliqueInnermost: oblique

Relations of the StomachRelations of the Stomach

◙◙ Anterior: Anterior:

– DiaphragmDiaphragm– Left lobe of the liverLeft lobe of the liver– Left costal cartilageLeft costal cartilage– Anterior abdominal wallAnterior abdominal wall

◙◙ Posterior )stomach bed(: Posterior )stomach bed(:

– DiaphragmDiaphragm– Left suprarenal glandLeft suprarenal gland– Left kidneyLeft kidney– PancreasPancreas– Spleen and splenic arterySpleen and splenic artery– Transverse colon and Splenic Flexure.Transverse colon and Splenic Flexure.

◙◙ Stomach lie: Stomach lie: The fundus of the stomach is located posterioly while the pyloric The fundus of the stomach is located posterioly while the pyloric antrum is very near to the anterior abdominal wall; so with barium studies)1( In the antrum is very near to the anterior abdominal wall; so with barium studies)1( In the erect position: Air fluid level seen.)2( Supine: barium fill the fundus while pyloric erect position: Air fluid level seen.)2( Supine: barium fill the fundus while pyloric region is seen in double contrast.)3( Prone: barium fill the pylorus while the fundus is region is seen in double contrast.)3( Prone: barium fill the pylorus while the fundus is seen in double contrast.seen in double contrast.

◙◙ Incisura:Incisura: is that part of the stomach where there is sudden change in the plan of the is that part of the stomach where there is sudden change in the plan of the stomach from the vertical to the horizontal; it help to show whether the stomach is stomach from the vertical to the horizontal; it help to show whether the stomach is eutonic, hypertonic or hypotonic according to its level in comparison with the 1eutonic, hypertonic or hypotonic according to its level in comparison with the 1stst part part of the duodenum.of the duodenum.

Small intestineSmall intestine

◙◙ Extension: Extension: From pyloric orifice of stomach to ilio-caecal valveFrom pyloric orifice of stomach to ilio-caecal valve

◙◙ Length: Length: 6 meters (range, 3-10)6 meters (range, 3-10)

◙◙ 3 Parts:3 Parts:1.1. DuodenumDuodenum2.2. JejunumJejunum3.3. IleumIleum◙◙ Movements:Movements:1.1. RhythmicRhythmic2.2. PendularPendular3.3. PeristalticPeristaltic

DuodenumDuodenum

◙◙ C-shaped around the head of pancreasC-shaped around the head of pancreas

1.1. Duodenal bulb: 2 inches, level of L-1, conical shape Duodenal bulb: 2 inches, level of L-1, conical shape 2.2. Descending: 3 inches, level of L-2Descending: 3 inches, level of L-23.3. Transverse: 4 inches, level of L-3Transverse: 4 inches, level of L-34.4. Ascending: one inch, level of L-2Ascending: one inch, level of L-2NB: 1. Duodenal bulb )Cap(: is a common site of ulcers. It likely seen better in the right NB: 1. Duodenal bulb )Cap(: is a common site of ulcers. It likely seen better in the right

anterior oblique.anterior oblique.2. Descending part: forms a curve around the head of the pancreas; the common bile 2. Descending part: forms a curve around the head of the pancreas; the common bile

duct and the pancreatic duct open by a common opening duct and the pancreatic duct open by a common opening )ampulla of Vater( = )ampulla of Vater( = {duodenal papilla} {duodenal papilla} : through it. The opening is surrounded by : through it. The opening is surrounded by sphincter of Oddi. sphincter of Oddi.

3. During contrast examination; barium reach the duodenal cap after 5minutes, delay 3. During contrast examination; barium reach the duodenal cap after 5minutes, delay emptying more than 15 minutes may be due to obstruction. emptying more than 15 minutes may be due to obstruction.

◙ ◙ 4 parts:4 parts:

◙ ◙ The shortestThe shortest

◙ ◙ TheThe widestwidest

Relations of the DuodenumRelations of the Duodenum

1.1. Duodenal bulb:Duodenal bulb:– Superior and anterior: liver and Superior and anterior: liver and

gall bladdergall bladder– Inferior: head of pancreasInferior: head of pancreas– Posterior: common bile duct, Posterior: common bile duct,

portal veinportal vein2.2. Descending:Descending:

– Posterior: right kidneyPosterior: right kidney– Medial: head of pancreasMedial: head of pancreas– Lateral: colon (HF) Lateral: colon (HF)

3.3. Transverse:Transverse: – posteriorly crosses (Rt. Psoas posteriorly crosses (Rt. Psoas

muscle, IVC, aorta)muscle, IVC, aorta)4.4. Ascending:Ascending:

– Posterior: lt. Psoas, lt. renal Posterior: lt. Psoas, lt. renal vein, inferior mesenteric vein)vein, inferior mesenteric vein)

– Anterior: transverse colonAnterior: transverse colonSmall intestine: 6-7 m surrounded by the Small intestine: 6-7 m surrounded by the

peritoneum ,so it is freely mobileperitoneum ,so it is freely mobile

Large intestineLarge intestine

◙◙ Length:Length: • 1.5 m 1.5 m

• Extend from ileum to anusExtend from ileum to anus

• Characteristic shape: Characteristic shape:

Haustrated appearance Haustrated appearance

caused by the longitudinal caused by the longitudinal

Muscle fibers being shorter Muscle fibers being shorter

Than the circular muscleThan the circular muscle

Fibers; they run usually in Fibers; they run usually in

Three bonds called:Three bonds called:

taenia coli. taenia coli.

PartsParts

◙◙ Rectum:Rectum:

◙◙ CaecumCaecum::

◙◙ Colon:Colon:

◙◙ Anal canal:Anal canal:

Large intestineLarge intestine

Caecum & ColonCaecum & Colon

◙◙ Caecum:Caecum: – 6 cm long, 6 cm long,

– The widest (7.5-9 cm) The widest (7.5-9 cm)

– Ilio-caecal valve (ICV): Ilio-caecal valve (ICV): posteromedial aspect posteromedial aspect

Appendix : Appendix :

– 12-24 cm length, 12-24 cm length, retrocaecal (75%)retrocaecal (75%)

Caecum & ColonCaecum & Colon

◙◙ Colon:Colon: AscendingAscending: :

– 15 cm length, HF ? 15 cm length, HF ?

Transverse:Transverse:

– 50 cm length, SF, 50 cm length, SF, transverse mesocolon transverse mesocolon

Descending: Descending:

– 25 cm length, pelvic brim25 cm length, pelvic brim

Sigmoid colon: Sigmoid colon:

– 40 cm length, S-shaped40 cm length, S-shaped

– Most movable ; may be Most movable ; may be

Too longToo long

Rectum & Anal canalRectum & Anal canal

◙◙ Rectum:Rectum:

– Level of 3Level of 3rdrd sacral V. (2 cm ant. to tip of coccyx) sacral V. (2 cm ant. to tip of coccyx)

– 12 cm length12 cm length

– S-shaped (upper, middle and lower thirds), valve of HoustonS-shaped (upper, middle and lower thirds), valve of Houston

– Lower third: no peritoneal cover, dilated (rectal ampulla)Lower third: no peritoneal cover, dilated (rectal ampulla)

– Pre-sacral space: Pre-sacral space: it is the space between the rectum and the sacrum(0.6-it is the space between the rectum and the sacrum(0.6-1.2cm)1.2cm)

Examined by the lateral view during barium enema studies to detect tumors , Examined by the lateral view during barium enema studies to detect tumors , crohn’s disease and ulcerative colitis.crohn’s disease and ulcerative colitis.

◙◙ Anal canal:Anal canal:

– Right angle with rectumRight angle with rectum

– Sphincters: internal (involuntary), external (voluntary)Sphincters: internal (involuntary), external (voluntary)

– NB: The lower part of the rectum and the anal canal form two antero-posterior NB: The lower part of the rectum and the anal canal form two antero-posterior curves (S-shape) this fact must be remembered when a rectal tube or enema is curves (S-shape) this fact must be remembered when a rectal tube or enema is inserted to avoid serious injury. This area also have rich supply with vagus nerve; inserted to avoid serious injury. This area also have rich supply with vagus nerve; so sever stretch or extreme temperature may lead to shock.so sever stretch or extreme temperature may lead to shock.

Rectum & Anal canalRectum & Anal canal

Biliary SystemBiliary System

◙◙ Gall Bladder:Gall Bladder:

◙◙ Biliary Ducts:Biliary Ducts:

Gall BladderGall Bladder

◙◙ Pear-shaped sacPear-shaped sac

◙◙ CapacityCapacity: : 50 cc (store conc. Bile secreted by the liver. 50 cc (store conc. Bile secreted by the liver.

◙◙ Site:Site: inferior surface, right lobe of the liver ; there is a wide range of variation of the gall inferior surface, right lobe of the liver ; there is a wide range of variation of the gall bladder position from the 1bladder position from the 1stst lumber vertebra to the level of the 5 lumber vertebra to the level of the 5thth lumber vertebra ; due lumber vertebra ; due to this position ; gall bladder stones overlaps the same area of right renal stones . Right to this position ; gall bladder stones overlaps the same area of right renal stones . Right lateral view may help to differentiate since gall bladder stones will be thrown anteriorly. lateral view may help to differentiate since gall bladder stones will be thrown anteriorly. NB: 15% only from gall bladder stones are radio-opaque.NB: 15% only from gall bladder stones are radio-opaque.

Mechanism of bile secretion: Gall bladder contracts and secrete bile under the effect of Mechanism of bile secretion: Gall bladder contracts and secrete bile under the effect of cholecystokinin enzyme stimulated by the presence of fats in the stomach.cholecystokinin enzyme stimulated by the presence of fats in the stomach.

◙◙ SizeSize: 10 cm length, 3 cm width: 10 cm length, 3 cm width

◙◙ PartsParts::

1.1. FundusFundus: anterior abdominal wall, 9: anterior abdominal wall, 9thth costal cartilage costal cartilage2.2. Body:Body: upward, backward and to the left upward, backward and to the left 3.3. Neck:Neck:

• Upward and forward, then sharply downwards Upward and forward, then sharply downwards • S-shaped, S-shaped, • Cystic duct (3 cm length), Cystic duct (3 cm length), • Mucosa: spiral valveMucosa: spiral valve

Biliary DuctsBiliary Ducts

◙◙ Hepatic ductsHepatic ducts: right and left: right and left

◙◙ Common hepatic duct: Common hepatic duct: 3 cm length3 cm length

◙◙ Common bile ductCommon bile duct: :

– Common hepatic + cystic ductCommon hepatic + cystic duct

– 7 cm length7 cm length

– Relations:Relations:

• Supra-duodenal part: in front Supra-duodenal part: in front of portal veinof portal vein

• Retro-duodenal: first part of Retro-duodenal: first part of duodenumduodenum

• Retro-pancreatic:Retro-pancreatic:

– Unites with pancreatic duct: Unites with pancreatic duct: enter 2enter 2ndnd part of duodenum part of duodenum

PancreasPancreas

•5" long / 1" thick•Head close to curve in

C-shaped duodenum

•pancreatic duct joins common bile duct from liver

•Opens 4" below pyloric sphincterRegions: Head, body, tail

AP ABDOMEN

COLON

STOMACH

SM. BOWEL

Normal abdominal gas pattern with air in the stomach and scattered non-distended loops of large and small bowel.

Barium swallow, esophagus.

Oblique view

The normal impressions made by :The normal impressions made by :

)A( aortic arch, )A( aortic arch,

)B( left mainstem bronchus, and )B( left mainstem bronchus, and

)LA( left atrium on the esophagus)LA( left atrium on the esophagus..

NORMAL GASTRIC ANATOMY

C-LOOP

FUNDUS

BODYANTRUM

JEJUNUM

DUODENUM

Barium Meal

HEPATIC FLEXURE

SPLENIC FLEXURE

TRANSVERSE COLON

CECUM

AS

CE

ND

ING

CO

LON

DE

SE

ND

ING

CO

LON

TERMINAL ILEUM

NORMAL COLON

Barium Enema

CT abdomen

CT abdomen