Intestines Differences Between Jejunum and Ileum Types Jejunum Ileum Color Deeper red Paler pink Calibre Bigger Smaller Thickness of wall Thick and Heavy Thin and Lighter Vascularity Highly vascularised Less vascularised Vasa Recta Longer Shorter Arcades Few loops Many loops Fat in Mesentery Less More Large Small Plicae Circularis Tall Short Closely packed together Sparse, completely absent at distal part Lymphoid Nodule Lesser Many (Payer s patches) o Antimesenteric side Characteristics of the Duodenum Has 4 parts o 1 st part (Superior) (L1) Duodenal cap Intraperitoneal (Hepatoduodenal ligament) No folding Gastorduodenal junction marked by Prepyloric vein o 2 nd part (Descending part) (L2-3) Ampula of Vater open into (Spinhter of Oddi) Retroperitoneal Presence of circular fold o 3 rd part (Horizontal part) (L3) Follows the body of Pancreas Crossed by SMA Retroperitoneal o 4 th part (Ascending part) (L2) Duodenaljejunal junction marked by Ligamentum Treitz Retroperitoneal Presence of Brunner s gland Blood supply o Before opening of Bile duct Superior Pancreaticoduodenal artery branch of Celiac Trunk o After the opening of Bile duct Inferior Pancreaticoduodenal artery branch of SMA
Rectum Ascending Colon Descending Colon Middle Colic Superior Colic MIDGUT HINDGUT Caecum Appendix 2/3 rd Transverse Colon 1/3 rd Transverse Colon Right Colic Illiocaecal Caecal Appendiceal SMA IMA Sigmoid Colon Anal canal Left Colic Sigmoidal Characteristics of Large Intestines Consists of o Colon Ceacum Ascending Transverse Descending Sigmoid o Appendix o Rectum o Anal canal All are Retroperitoneal except o Transverse Colon Suspended by Transverse Mesocolon o Sigmoid Colon Suspended by Sigmoid Mesocolon o Caecum o Appendix Suspended by Mesoappendix Has 2 flexures o Hepatic/ Right Colic flexure o Splenic/ Left Colic flexure Divided into Midgut and Hindgut at the 2/3 rd Transverse Colon o Midgut supplied by SMA o Hindgut supplied by IMA Characteristics of Colon o Haustra (due to Taenia coli) o 3 bands of Taenia Coli o Appendices Epiploicea o Plicae Semilunaris
Rectum Anterior Posterior Characteristics 3 lateral curvatures o One convex to the left Begins at the Rectosigmoidal junction o Marked by confluence of Taenia coli 3 Houston s fold Peritoneal pouches o Anterior Male Rectovesicle pouch Female Douglas pouch o Lateral Pararectal fossa o Inferiorly Fascia of Denonvillier s Peritoneum Rectum Upper 1/3 rd Supplied by artery branch of IMA vein IMV Middle 1/3 rd Supplied by Middle Rectal artery branch of Internal Iliac Middle Rectal vein Internal Iliac vein Lower 1/3 rd Supplied by Inferior Rectal artery branch of Internal Pudendal Inferior Rectal vein Internal Pudendal vein Lateral view
Celiac Trunk Splenic Splenic branch Spleen Pancreatic branch Neck, body and tail of Pancreas Inferior Phrenic Short Gastric Fundus of Stomach Left Gastroepiploic Greater curvature of Stomach Left Gastric Esophageal Esophagus Hepatic Right Gastric Gastric branch Lesser curvature of Stomach Gastroduodenal Right Gastroepiploic Greater curvature of Stomach Abdominal Aorta Common Hepatic Supraduodenal Cystic Gallbladder Left Liver Superior Pancreaticoduodenal Anterior Head of Pancreas and Duodenum Posterior Right Liver Anterior Posterior Inferior Pancreaticodudodenal Ileum Inferior Mesenteric Artery Superior Mesenteric Artery Jejunal and Illial Jejunum Left Colic Sigmoidal Superior Colic Illioceacal Superior branch Descending Colon Distal 1/3 rd Transverse Colon Right Colic Ascending Colon Inferior branch Sigmoid Colon Middle Colic Caecal Appendiceal Superior part of Rectum Proximal 2/3 rd Transverse Colon Ceacum Appendix
Blood Supply of the Rectum and Anal Canal Inferior Mesenteric Artery Left Branch Left Branch Abdominal Aorta Upper I/3 rd of the Rectum and Upper Anal Canal External Iliac Common Iliac Middle 1/3 rd of Rectum Lower 1/3 rd of Rectum and Lower Anal Canal Internal Iliac Middle Rectal Inferior Rectal Internal Pudendal
Differences Between Upper and Lower Anal Canal Features Upper Anal Canal (Above Pectinate Line) Lower Anal Canal (Below Pectinate line) Embryological Origin Endoderm Ectoderm Simple Columnar Stratified Squamous Epithelium of Mucosa Non-keratinized (above Hilton s line) Keratinized (below Hilton s line) artery Inferior Rectal artery Arterial Supply Branch of IMA Branch of Internal Pudendal artery of Internal Iliac artery Venous drainage Superior rectal vein Inferior Mesenteric Internal Pudendal vein Internal Iliac vein vein Portal vein Inferior Vena Cava Lymphatic Drainage Internal Iliac Nodes Superficial Inguinal Lymph nodes Autonomic Hypogastric Plexus Inferior Rectal nerve branch of Pudendal Only sensitive to stretch nerve Sensitive to Innervations o Pain o Temperature o Touch o Pressure Types of Haemorrhoids Internal Haemorrhoid vein varicosity Covered by Mucosa Not painful External Haemorrhoid Inferior Rectal vein varicosity Covered by skin Painful
Greater curvature of stomach Superior Mesenteric Vein Portal System Uncinate process of Pancreas 3/4 th of Duodenum Paraumbilical Left lobe Small Intestines Pancreatic Caudate lobe Colon 1/3 rd Transverse Sigmoidal Left Gastric Inferior Mesenteric Vein Splenic vein Hepatic Portal Vein Quadrate lobe Right lobe Left Colic Short Gastroepiploic Cystic vein Inferior Rectal Internal Pudendal Internal Iliac Middle Rectal Hepatic vein Portal Systemic Anastomoses and Their Clinical Conditions Prepyloric vein Right Gastric IVC Esophageal branch of Left Gastric vein o Esophageal varices Esophagus Left Gastric vein o Haemorrhoid Accessory Hemizygous Vein SVC Paraumbilical vein o Caput Medusa HEART Right, Middle, Superior, Left Colic veins