Radiographic Anatomy Digestive System Educational Objectives By the

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.

References 1. Text book of radiographic positioning and related anatomy; by Kenneth L. Bontrager, 6 th 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 Websites http: //www 6. district 125. k 12. il. us/science/anatomy/ http: //www. innerbody. com/htm/body. html http: //www. e-radiography. net/ http: //www. getbodysmart. com/index. htm 4

Digestive System (gastrointestinal; GI tract) – Stomach A. Fundus (fluid level seen in erect position) A. Body B. Pyloric Antrum – Small intestines (small bowel) A. Duodenum ("c" shape; bulb) B. jejunum C. ileum

Digestive System gastrointestinal; GI tract) Large intestine (colon) A. B. C. D. E. F. G. H. n Caecum (valve; appendix) Ascending colon Hepatic flexure Transverse colon Splenic flexure Descending colon Sigmoid colon (flexure) Rectum and anal canal Accessory GI tract organs A. Salivary glands B. Liver &Gall bladder C. Pancreas

Quadrants & Regions of the abdomen • Abdomen divisions 4 Quadrants (clinically) 9 Regions (anatomically)

Quadrants & Regions of the abdomen MSP: mid-sagittal plane TUP: transumblical plane (L 4/5) RLL: right lateral plane LLL : left lateral plane TPP: transpyloric plane (L 1) TTP: transtubercular plane (L 5)

Regions of the abdomen

Digestive System (I): Alimentary canal: – 9 m length – Extend from mouth to anus ►Oral cavity ►Pharynx ►Esophagus ►Stomach ►Intestine (small & large) (II): Accessory organs: – – – Salivary glands Pancreas Liver and biliary system

Pharynx ◙ Levels : from skull base to level of C-6 (13 cm). ◙ 3 parts: (I): Nasopharynx: • • • Skull base to the level of soft palate Anterior: nasal cavity (posterior nares) Inferior: nasopharyngeal isthmus Lateral wall: opening of auditory tube Roof: adenoid (II): Oropharynx: • Level of soft palate to tip of epiglottis • Anterior: oropharyngeal isthmus (III): Laryngopharynx: • Tip of epiglottis to level of C-6 • Pyriform fossa

Esophagus ◙ Levels : from C-6 to T-11 (25 cm). Normal points of narrowness: (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 communication between portal and systemic veins; any obstruction of the portal venous system may lead to oseophageal varices. ◙ Relations: (3 areas) (I): In the neck: • Anterior: trachea, thyroid • Posterior: cervical vertebrae • Lateral: common carotid artery (II): In the thorax: • Anterior: trachea, Lt. main bronchus, Lt. atrium • Posterior: thoracic vertebrae, thoracic duct, descending aorta • Lateral: – Right side: azygous vein, right lung – Left side: • Superior med. : Lt. subclavian artery, aortic arch, Lt. lung • Inferior med. : descending aorta, Lt. lung (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 (submerged segment) and help to prevent reflux from the stomach. Other factors: Acute gastro-oesophageal angle, pressure of right crus of the diaphragm and intrinsic muscles sphincter.

Stomach ◙ Shape: J-shaped, but may varies (volume, position, resp. , build) ◙ 2 Orifices: 1. 2. Cardiac Pyloric 1. 2. Lesser Greater ◙ 2 Curvatures: ◙ 3 Parts: 1. Fundus (air bubble) 2. 3. Body Antrum ◙ Mucosa: gastric rugae - Longitudinal: on lesser curvature - Random (mosaic): elsewhere ◙ Muscles: 1. 2. 3. Outer: longitudinal Inner: circular Innermost: oblique

Relations of the Stomach ◙ Anterior: – – Diaphragm Left lobe of the liver Left costal cartilage Anterior abdominal wall ◙ Posterior (stomach bed): – – – Diaphragm Left suprarenal gland Left kidney Pancreas Spleen and splenic artery Transverse colon and Splenic Flexure. ◙ Stomach lie: 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 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 seen in double contrast. ◙ Incisura: 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 eutonic, hypertonic or hypotonic according to its level in comparison with the 1 st part

Small intestine ◙ Extension: From pyloric orifice of stomach to ilio-caecal valve ◙ Length: 6 meters (range, 3 -10) ◙ 3 Parts: 1. Duodenum 2. Jejunum 3. Ileum ◙ Movements: 1. Rhythmic 2. Pendular 3. Peristaltic

Duodenum ◙ C-shaped around the head of pancreas ◙ The shortest ◙ The widest ◙ 4 parts: 1. Duodenal bulb: 2 inches, level of L-1, conical shape 2. Descending: 3 inches, level of L-2 3. Transverse: 4 inches, level of L-3 4. Ascending: one inch, level of L-2 NB: 1. Duodenal bulb (Cap): is a common site of ulcers. It likely seen better in the right anterior oblique. 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 (ampulla of Vater) = {duodenal papilla} : through it. The opening is surrounded by sphincter of Oddi. 3. During contrast examination; barium reach the duodenal cap after 5 minutes, delay emptying more than 15 minutes may be due to obstruction.

Relations of the Duodenum 1. 2. 3. 4. Duodenal bulb: – Superior and anterior: liver and gall bladder – Inferior: head of pancreas – Posterior: common bile duct, portal vein Descending: – Posterior: right kidney – Medial: head of pancreas – Lateral: colon (HF) Transverse: – posteriorly crosses (Rt. Psoas muscle, IVC, aorta) Ascending: – Posterior: lt. Psoas, lt. renal vein, inferior mesenteric vein) – Anterior: transverse colon Small intestine: 6 -7 m surrounded by the peritoneum , so it is freely mobile

Large intestine ◙ Length: • 1. 5 m • Extend from ileum to anus • Characteristic shape: Haustrated appearance caused by the longitudinal Muscle fibers being shorter Than the circular muscle Fibers; they run usually in Three bonds called: taenia coli.

Large intestine Parts ◙ Caecum: ◙ Colon: ◙ Rectum: ◙ Anal canal:

Caecum & Colon ◙ Caecum: – 6 cm long, – The widest (7. 5 -9 cm) – Ilio-caecal valve (ICV): posteromedial aspect Appendix : – 12 -24 cm length, retrocaecal (75%)

Caecum & Colon ◙ Colon: Ascending: – 15 cm length, HF ? Transverse: – 50 cm length, SF, transverse mesocolon Descending: – 25 cm length, pelvic brim Sigmoid colon: – 40 cm length, S-shaped – Most movable ; may be Too long

Rectum & Anal canal ◙ Rectum: – Level of 3 rd sacral V. (2 cm ant. to tip of coccyx) – 12 cm length – S-shaped (upper, middle and lower thirds), valve of Houston – Lower third: no peritoneal cover, dilated (rectal ampulla) – Pre-sacral space: it is the space between the rectum and the sacrum(0. 6 -1. 2 cm) Examined by the lateral view during barium enema studies to detect tumors , crohn’s disease and ulcerative colitis. ◙ Anal canal: – Right angle with rectum – Sphincters: internal (involuntary), external (voluntary) – 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 inserted to avoid serious injury. This area also have rich supply with vagus nerve; so sever stretch or extreme temperature may lead to shock.

Rectum & Anal canal

Biliary System ◙ Gall Bladder: ◙ Biliary Ducts:

Gall Bladder ◙ Pear-shaped sac ◙ Capacity: 50 cc (store conc. Bile secreted by the liver. ◙ Site: inferior surface, right lobe of the liver ; there is a wide range of variation of the gall bladder position from the 1 st lumber vertebra to the level of the 5 th lumber vertebra ; due 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. NB: 15% only from gall bladder stones are radio-opaque. 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. ◙ Size: 10 cm length, 3 cm width ◙ Parts: 1. 2. 3. Fundus: anterior abdominal wall, 9 th costal cartilage Body: upward, backward and to the left Neck: • Upward and forward, then sharply downwards • S-shaped, • Cystic duct (3 cm length), • Mucosa: spiral valve

Biliary Ducts ◙ Hepatic ducts: right and left ◙ Common hepatic duct: 3 cm length ◙ Common bile duct: – Common hepatic + cystic duct – 7 cm length – Relations: • Supra-duodenal part: in front of portal vein • Retro-duodenal: first part of duodenum • Retro-pancreatic: – Unites with pancreatic duct: enter 2 nd part of duodenum

Pancreas • 5" long / 1" thick • Head close to curve in • • C-shaped duodenum pancreatic duct joins common bile duct from liver Opens 4" below pyloric sphincter Regions: Head, body, tail

AP ABDOMEN STOMACH COLON 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 : (A) aortic arch, (B) left mainstem bronchus, and (LA) left atrium on the esophagus.