THE ABDOMEN CLINICAL EXAMINATION OF THE ABDOMEN

Transcription

1 THE ABDOMEN Clinical Examinatin f the Abdmen Anterir Abdminal Wall Inguinal Regin Peritneum Summary by Gut Derivatives Stmach Spleen Dudenum Pancreas Liver Gallbladder Small Intestine Large Intestine Abdminal Vasculature Nervus System Psterir Abdminal Wall Kidneys and Suprarenal Glands Lymphatic System Tw kinds f pain: CLINICAL EXAMINATION OF THE ABDOMEN Visceral Pain: Deep, thrbbing, delcalized pain, assciated with the visceral rgans. Smatic Pain: Sharp, piercing, pain lcalized t the abdminal wall. Abdminal Medical Histry: (pqr) 2 st 3 P -- Prvking: What have yu nticed that makes this pain wrse? P -- Palliating: What relives the pain? Q -- Quantity: Hw much pain are yu having? Q -- Quality: What des the pain feel like? R -- Regin: Where is the pain? R -- Radiatin: Des the pain g (radiate) t any ther lcale? S -- Severity: Hw des it keep them frm ding what they nrmally wuld d? T -- 3 time related questins Did the pain just start (suddenly) r cme n gradually? Is the pain cnstant r des it cme and g? Is the first time yu ever had this r have yu nticed anything like this befre? OBSERVE: Watch patient walk t table. Lk fr visible pain and discmfrt. Nte vital signs, stretch marks, scars, vascular pattern, etc. LISTEN (AUSCULTATE): Listen fr fluid sunds -- mix f fluid and gas mixing by peristalsis. If yu hear nthing, listen up t five minutes befre cncluding there are n bwel sunds. It can take a while. Listen fr bld flw. In sme slender peple yu can hear turbulent flw. Listen fr Frictin Rub, which ccurs when inflamed rgans rub next t each ther. Listen fr transmissin f sunds frm chest. PERCUSSION: Best way t examine liver is by percussin, t feel fr brders. Can percuss fr spleen t determine if it is enlarged. 1

2 PALPATE: Feel all majr rgans fr inflammatins, abnrmalities, psitin, etc. Fur Quadrants: Midsagittal Plane: Vertical line ging thrugh the middle f the abdmen. Transumbilical Plane: Hrizntal line ging thrugh the umbilicus. Fur Quadrants based n thse planes: Right Upper Quadrant: RUQ Right Lwer Quadrant: RLQ Left Upper Quadrant: LUQ Left Lwer Quadrant: LLQ Nine Regins: Vertical lines f divisin: Left and Right Mid-Clavicular Lines Hrizntal lines f divisin: Transpylric Plane: Smetimes used. It is halfway between the jugular ntch and the pubic bne. Subcstal Plane: Upper plane, passing thrugh the inferir-mst margin f the ribs. Transtubercular Plane: The line transversing the pubic tubercle. Divisins: Upper: Right Hypchndriac, Epigastric, Left Hypchndriac Middle: Right Lumbar, Umbilical, Left Lumbar Lwer: Right Inguinal, Hypgastric (Suprapubic), Left Inguinal Bundaries f the Abdmen: ANTERIOR ABDOMINAL WALL Superir Bundary: The diaphragm. It extends t ICS-5 superirly (at the median line; it is mre inferir arund the edges). Hence the superir limit f the liver is als ICS5 since it push up int the diaphragm. Psterir Bundary: Lumbar Vertebrae, and Quadratus Lumbrum and Transverse Abdminis muscles. Anterlateral Brders: The muscles f abdminal wall: transversus abdminis, and internal and external abdminal blique. Inferir Brders: The Pelvic Brim PELVIC BRIM: Inferir brder f the abdmen. It cnsists f the Right and Left Cxal Bnes. Each cxal bne is made up f an ilium, ischium, and pubic bne. Iliac Crest: The superir prtin f the iliac bne. The Iliac Tubercles are bny prminences n the iliac crest. Anterir Superir Iliac Spine (ASIS): The anterir mst feature n the iliac crest. Pubic Tubercle: Lateral edge f pubic bne. Inguinal Ligament: Fund between the ASIS and the pubic tubercle, running in the same directin as the ASIS. The femral vessels and the inguinal canal are bth related t the inguinal ligament. Frmed frm apneursis part f the external abdminal blique. UMBILICUS: Fund between L3 and L4 in physically fit persns. Grandparents Like Pediatric Dctrs Preventing Kids Sickness: One Transpylric Plane -- The Transpylric plane passes thrugh L1 and cntains the fllwing structures: Gall-bladder 2

3 Liver Pylrus f Stmach Dudenal Bulb (Dudenum I) Pancreas Bdy and Tail Kidneys Spleen Prcessus Vaginalis: The prtin f peritneum that remains with the testes when they descend int the scrtum. Anything that pushes thrugh the anterir abdminal wall will becme invested with peritneum. The testes push thrugh the wall, but nrmally a piece f peritneum is left behind as the prcessus vaginalis. When the testes descend, the peritneum ges with it and then scales back. The prtin f peritneum that remains with the testes is called the prcessus vaginalis. 7 Layers f the Abdminal Wall: Skin Epidermis -- the part we shed Dermis -- cntains nerves, capillaries, sweat glands, hair fllicles. Has cllagen fibers that tend t be hrizntal, frming the creasing f the skin. These are called Langer's Lines. In surgery, yu shuld cut with Langer's Line, the directin f the cllagen, s as t minimize surgical scars. Superficial Fascia -- Cnnective tissue that is nt apneursis, tendn, r ligament. This is the same thing as the hypdermis. Camper's Fascia: Fatty layer, first f the tw layers. It is fund thrughut. Scarpa's Fascia: Lwer layer, fund in the lwer 1/3 f the anterir abdminal wall. It has a restrictive lcatin, defined by the extent f damage ccurring with a straddle injury. Limits: The area is restricted t the anterir abdminal wall. Lateral Limit: Basically the inguinal ligament, where it intersects with fascia lata, s that fluid des nt pass int the thigh. Inferir Limit = the base f the scrtum. Psterir Limit = it ges back t the anus, and fills the pelvis in between. The utlined regin is called the superficial perineal space. It is called different fascia at different places: Darts Fascia in scrtum / labia majra, and Clles Fascia arund perineum. Fundifrm Ligament: The false suspensry ligament f the penis r clitris. It is an extensin f superficial fascia. Deep Fascia A true suspensry ligament ccurs in the deep fascia layer, which extends int the penis / clitris. S, we have bth a true suspensry ligament (deep fascia) and a false ne (fundifrm ligament / superficial fascia). Deep fascia encmpasses all muscles f the entire bdy. Muscles -- Three flat muscles plus the lngitudinal rectus sheath muscle. External Abdminal Oblique -- muscle fiber directin is anter-inferir (like external intercstals -- hands in pcket). Originate at brder f Thracic ribs T5 - T12 Extends t midline and attaches n linea alba. Als attaches t the iliac crest. Again, the apneursis prtin f the externals frm the inguinal ligaments. Als frms the superficial inguinal ring, which allws passage f the spermatic crd (male) r rund ligament (female). Superficial Inguinal Ring is made up f tw cmpnents, lateral crus and medial crus. Intercrural fibers separate the tw. Internal Abdminal Oblique Als has fibers that attach alng the inguinal ligament t the pubic crest. Directin f fibers tends t g utward, frm medial t lateral and a little bit inferirly (inferlaterally). Brders n ribs

4 The apneursis splits and ges bth anterirly (t merge with external apneursis) and psterirly (t merge with transversus apneursis) Transversus Abdminis Deep mst layer f flat muscles. Als brders n ribs Extends dwn t the pubic crest and medially t the linea alba. It creates a diagnal pathway fr the spermatic crd r rund ligament t pass thrugh. Fibers run transversely! -- hrizntally frm lateral t medial. Rectus Abdminis: Straight muscle. Passes frm Xiphid Prcess inferirly t pubic symphysis (inferir center f pubic bne). Rectus Sheath hlds this rectus muscle in place. It is directly shallw t it, frmed by the apneurses f the three flat muscles. It has a psterir and anterir layer, frmed frm the apneurses f the three flat muscles. Upper 3/4 f Abdminal Wall: All three muscle layers cnverge n rectus sheath, and pass bth anterirly (external apneursis) and psterirly (transversus apneursis). This part f the wall is suturable in surgery. Lwer 1/4 f abdminal wall is transversalis fascia. Here, all three muscle layers pass anterirly. Here it is called transversalis fascia. This part f the wall is nt suturable in surgery. Arcuate Line: The line that divides the upper 3/4 f abdmen frm lwer 1/4, by the differences in the apneurtic layers. Transversalis Fascia -- Deep fascia n the interir (deep) surface f the transversus abdminis muscle. Esp. fund in the lwer 1/4 f the abdmen. It has several names, but it is ne cntinuus plane f fascia, just utside the peritneum. As a cntinuus plane, it is als an avenue fr infectin. Subserus Fascia Peritneum: A serus membrane that secretes fluid, thus allwing internal rgans frictinless mvement. Linea Alba: The best place t make a surgical cut and nt hit any nerves is straight dwn the linea alba. NERVOUS SUPPLY f Anterir Wall: Ventral Rami f T7 - T12, and L1. Dermatmes: Hw nerves innervate the anterir abdminal wall -- in sectins. Referred Pain: Example T10 ges t umbilical regin. Appendicitis pain will g t sympathetic nervus system > refers back t T10. When rupture ccurs, txins are released and irritate the peritneum, resulting in a lcalized effect. Iliinguinal Nerve: Ges thrugh the inguinal canal, with the spermatic crd (male) r rund ligament (female). Supplies scrtum (r labia majra) and medial aspect f thigh. Ilihypgastric Nerve: Directly superir t iliinguinal nerve. Innervates the suprapubic area. Bth Iliinguinal and Ilihypgastric may cme ff as a single nerve and branch later. McBurney's Pint: The pint f surgical incisin fr an appendectmy. Is lcated n a line alng the ASIS. The ilihypgastric nerve is right there, abut 1cm superir t the ASIS, s that is the nerve that ya gtta be weary f when ding an appendectmy. ARTERIAL SUPPLY f Anterir Wall: Superir Epigastric Artery -- Runs directly ver rectus abdminis muscle. Inferir Epigastric Artery Superficial Epigastric Artery VENOUS SUPPLY f Anterir Wall: The same as the veins abve. When using a needle t drain peritneal fluid, d nt hit the Superir r Inferir epigastric veins! The result wuld be massive bleeding. 4

5 INGUINAL REGION Inguinal Canal: Frmed frm the apneurses f the three flat muscles. It a diagnal passage. Mst tubular structures pass thrugh membranes diagnally, as the ureters and fallpian tubes d. This prvides reinfrcement n the wall f the structure being entered. Cntents f Inguinal Canal Spermatic Crd (male) r Rund Ligament (female) Iliinguinal Nerve Genital Branch f the Genitfemral Nerve. Inguinal Triangle (Hesselbach's Triangle): An area f weakness in the apneursis, where direct hernias can ccur. Brders: The lateral margin f the rectus muscle (aka semilunaris) The Inferir Epigastric Artery The Inguinal Ligament CONJOINT TENDON: The space f membrane where the transversus abdminis and internal blique apneurses jin int ne. It is an area f weakness in the abdminal wall. HERNIAS: The prtrusin f intraperitneal guts utside f the peritneum (i.e. thrugh the peritneal wall). DIRECT INGUINAL HERNIA: Gut ges straight thrugh the inguinal triangle, thrugh the cnjint tendn. It will be lcated medial t the inferir epigastric artery INDIRECT INGUINAL HERNIA: Hernia that passes thrugh the inguinal canal and riginates lateral t the inferir epigastric artery. Cngenital Indirect: The weakness was present at birth. Agenesis: Absence f grwth r clsure f sme part f the abdminal wall. Dysgenesis: Incrrect r dysfunctinal grwth. Acquired Indirect: Ascites -- (fluid buildup in peritneum) Obesity Pregnancy Surgical Incisins Diaphragmatic Hernias: HIATAL HERNIA: Distal end f the esphagus can draw itself back int the esphageal hiatus, pulling part f the stmach with it. Referred pain frm a hiatal hernia ccurs in Epigastric regin, arund T7-T8. Semilunar Hernias: Occur alng the rectus sheath and arcuate lines, mstly. PERITONEUM Spleen: It is actually mesdermal in rigin, nt enddermal like the rest f the abdminal rgans. Retrperitneal Space: The area behind (psterir t) the peritneum. Any rgans nt cmpletely (r almst cmpletely) cvered by peritneum are cnsidered retrperitneal rgans. Abdminal Cavity: Everything but the lateral, psterir, and anterir bdy walls f the abdmen, including bth the peritneal cavity and the retrperitneal space. 5

6 Peritneal Cavity: That part f the abdmen invaginated by peritneum. Peritneum has visceral and parietal layers, just like the pleural cavity. It is analgus t the rgans pushing themselves int the peritneum, like a fist int a balln. Visceral Peritneum: Peritneum directly n the rgans. Parietal Peritneum: Peritneum surrunding the interir lining f the abdminal wall. MALES: The peritneal cavity is CLOSED. FEMALES: The peritneal cavity is OPEN. It pens ut int the cervix and vagina, making it a ptential space fr pathgens t enter. Peritneum shuld be cnsidered a ptential space fr pathgens and fluids t build up. Subphrenic Recess: The recess where the peritneum reflects ff the liver (right side) n the inferir surface f the diaphragm. It cntains the crnary ligament f the liver. OMENTA: Peritneum surrunding the stmach Lesser Omentum: Peritneum alng the lesser curvature f the stmach, cvering the pancreas. It is superir and medial t the stmach and psterir t parts f the liver, and anterir t pancreas. Lesser Omental Bursa / Lesser Peritneal Sac: The space between the stmach and the liver. The space anterir t the lesser curvature f the stmach and psterir t the liver. EPIPLOIC FORAMEN: A pathway that allws entrance frm the lesser peritneal sac t the greater peritneal sac. The Inferir Vena Cava ges directly psterir t it (retrperitneal). The prtal triad is directly anterir t it, in the peritneum, alng the lesser curvature f the stmach. Greater Omental Bursa: The space between the stmach and anterir abdminal wall. Greater Omentum: The space frmed by the peritneum n the anterir surface f the stmach and the anterir abdminal wall. It attaches t the stmach and t the transverse cln. Anterir Layer f Greater Omentum: The parietal peritneum f the abdminal wall. Psterir Layer f Greater Omentum: The visceral peritneum alng the greater curvature f the stmach. Superir Recess: Where the Lesser Omentum stps at the crnary ligament f the liver and reflects back nt the liver. Essentially, the space between the stmach and Inferir Recess: Alng the greater curvature f the stmach, where the greater mentum reflects nt the transverse mescln. Essentially, the space between the stmach and transverse cln, inferir t the stmach. Intra-Peritneal Organs: Organs cmpletely r almst cmpletely enclsed by peritneum. Stmach Liver Gall Bladder Transverse Cln: cmpletely Jejunum Ileum Cecum (very start f ascending cln) Retr-Peritneal Organs: Organs that are lcated mstly r cmpletely behind the psterir parietal peritneum. Dudenum Ascending Cln (nly 25-50% cvered) Descending Cln (nly 25-50% cvered) Sigmid Cln Pancreas Kidneys 6

7 Great Vessels and their primary branches: Abdminal Arta and Inferir Vena Cava, Celiac Trunk, and Superir and Inferir Mesenteric arteries and veins. Mesentery: Tw layers f peritneum ppsing each ther. Vessels and nerves ften lie in the mesentery, where they can easily reach the rgan where the peritneal layers separate and reflect ff the rgans. THE Mesentery: The ne that cnnects the small intestine t the psterir abdminal wall. The rt f the mesentery is where the Mesentery cnnects t the psterir wall. Transverse Mescln: Specific mesentery cnnecting the transverse cln t the psterir peritneum. Sigmid Mescln: Specific mesentery cnnecting the sigmid cln t the psterir peritneum. The Anterir Surface f the Diaphragm: Vena Caval Framen: Hle fr the Inferir Vena Cava, where it passes t the liver. Arund T8 It is lcated in the central tendn (superir mst part) f the diaphragm. Esphageal Hiatus: Opening that admits the esphagus, guarded by tw muscles left crus and right crus. Left Gastric Artery and Left Gastric Vein als pass thrugh the esphageal hiatus. Passes thrugh at T10. Artic Hiatus: Is actually psterir t the diaphragm -- nt really a hle in the diaphragm. Thracic Duct ges psterir thrugh this pening as well as arta. Abut Level 12, at lwer mst part f diaphragm. Lumbcstal Arches: Transversalis Fascia n the psterir wall f the diaphragm. Sympathetic Ganglia cme thrugh alng these arches. FOREGUT: STRUCTURES: SUMMARY ACCORDING TO THE GUTS Stmach 1st tw parts f the dudenum: Dudenal Cap and Descending Dudenum. Liver Gall Bladder Pancreas ARTERIAL VASCULAR SUPPLY Branches f the Celiac Trunk LYMPHATIC SUPPLY Branches f the Celiac Ndes REFERRED PAIN: Occurs in the Epigastric Regin. VENOUS RETURN: The prtal vein. INNERVATION: Parasympathetic: Frm Vagus nerve (C10). It is perivascular -- it fllws the bld vessels. Sympathetic: Frm the Greater Thracic Splanchnic Nerves (T6-T10) MIDGUT: STRUCTURES: 7 Third and furth parts f dudenum: Hrizntal and Ascending Dudenum. Jejunum Ilium Cecum

8 Ascending Cln First 2/3 f Transverse Cln ARTERIAL VASCULAR SUPPLY Branches f the Superir Mesenteric Artery LYMPHATIC SUPPLY: Branches f the Superir Mesenteric Ndes. REFERRED PAIN: Occurs in the Umbilical Regin VENOUS RETURN: The Superir Mesenteric Vein. INNERVATION: Parasympathetic: Frm Vagus nerve (C10). It is perivascular -- frm the bld vessels. Sympathetic: Frm the Lesser Thracic Splanchnic (T9-T11,L1) HINDGUT: STRUCTURES: Distal 1/3 f Transverse Cln Descending Cln Sigmid Cln Rectum Upper prtin f anal canal. ARTERIAL VASCULAR SUPPLY Branches f the Inferir Mesenteric Artery LYMPHATIC SUPPLY: Branches f the Inferir Mesenteric Ndes. Exceptin: The upper and lwer rectum g t the Right and Left Cmmn Iliac ndes, which then drains straight t the Lumbar Chain Ndes, and then t Thracic Duct. REFERRED PAIN: Occurs in the Hypgastric (Suprapubic) regin. VENOUS RETURN: The Inferir Mesenteric Vein. INNERVATION: Parasympathetic: Frm Pelvic Splanchnic Nerves (S2-S4). Sympathetic: Frm the Upper Lumbar Splanchnic (L1-L2) DEVELOPMENT: THE STOMACH Stmach begins as a mere dilatin f the primitive gut tube. It underges tw basic prcesses: differentiatin and rtatin. Initially tube attaches t drsal and ventral walls via drsal and ventral mesenteries. Ventral Mesentery eventually becmes lesser mentum. Drsal Mesentery (Drsal Mesgastrium) eventually becmes greater mentum. Rtatin: Then the whle structure rtates 90 t the right, dragging the mesentery alng with it. The drsal mesentery becmes the left side f the bdy, and the psterir f the stmach becmes the left lateral aspect. Differential Grwth: Then differential grwth prduces the fundus, the greater curvature, and the lesser curvature f the stmach. LOCATION: The pylrus f the stmach at the level f L1, in the transpylric plane. Generally in the right epigastric regin, but the lcatin varies depending n psitin, weight, physilgy, etc. EXTERNAL MORPHOLOGY: Cardia: Superir part nearest the esphagus. Fundus: That part f the stmach that is actually superir t the abdminal esphagus. 8

9 Gastric Bubble is lcated here in radigraphs, if persn is upright. Cardiac Ntch is a radigraphic feature f being able t see the fundus part f the stmach. Bdy: The main part f the stmach cnsisting f the greater and leser curvatures. Greater Curvature: Inferir brder f stmach bdy. Lesser Curvature: Superir brder f stmach bdy. Pylric Regin: The mst distal part f the stmach, at level f L1, leading int dudenal cup. Gastrclic Ligament: On greater curvature f stmach, attaching t transverse cln. It is part f the greater mentum. INTERNAL MORPHOLOGY: Gastric Canal: Impressin alng the lesser curvature f the stmach, n the interir. Rugae here are mre lngitudinal, t guide fd t the pylrus. Cardiac Opening: The pening at the prximal end, aka the esphgastric junctin. N true sphincter here. Rugae: Mucsal flds f internal wall f stmach. They increase the surface area available fr digestin. Pylric Antrum: Pylric Canal: The distal regin f the bdy, in the pylric zne, leading t pylrus. Pylric Sphincter: At the pylrus, it is a true sphincter cntrlling flw f chyme int the dudenum. RELATIONSHIPS: The left lbe f the liver verlies the anterir prtin f the stmach. Spleen is lateral t the stmach, just ff the greater curvature. The greater mentum is inferir t the stmach (just ff greater curvature), and the transverse cln lies directly deep t it. Psterir t Stmach: The lesser peritneal sac. The pancreas, with the dudenum surrunding it. Bed f the Stmach: Thse rgans upn which the stmach lies. The pancreas, spleen, transverse cln, and a prtin f the kidney and suprarenal glands. CLINICAL CONSIDERATIONS: Gastric Bubble can be seen in stmach n X-rays, in the fundus regin. Stmach Carcinma is usually in the pylric regin r lwer bdy, clse t the pylric lymph ndes. Gastric (Peptic) Ulcers: Acid secretin in stmach. Gastrdudenal Artery, psterir t pylric area, can be affected by an ulcer if the wall is erded. VASCULAR / LYMPH SUPPLY: Pylric Lymph Ndes drain t the Celiac Ndes. Right and Left Gastric Arteries supply the lesser curvature f the stmach. They cme ff f the Celiac Trunk, via the cmmn r prper hepatic arteries. Right Gastrepiplic supplies greater curvature, frm the gastrdudenal, frm the prper hepatic. Left Gastrepiplic supplies greater curvature, frm the Splenic Artery, frm the Celiac Trunk. THE SPLEEN DEVELOPMENT: It is mesdermal -- nt derived frm gut (i.e. nngut) It grws within the tw layers f peritneum ging t the psterir wall -- within the tw flds defining the drsal mesgastrium. As the stmach rtates, the spleen is mved t the left f the stmach (lateral t stmach) The drsal mesgastrium in this regin becmes the gastrsplenic ligament. 9

10 Psterir part f mesgastrium adheres t the psterir wall, and the left kidney will then lie directly deep t it. This prtin f the mesentery becmes the splenrenal ligament. LOCATION: Upper left quadrant, left hypchndriac regin, articulated with ribs 9-11 (laterally). EXTERNAL MORPHOLOGY: It has three grves (surfaces) Renal Surface Gastric Surface Clic Surface: Anterir / Inferir extremity. Hilus: Cntains the splenic artery and vein, near the splenrenal ligament. INTERNAL MORPHOLOGY: RELATIONSHIPS: Kidney is deep t it, cnnected by splenrenal ligament. Stmach is medial t it, cnnected by gastrsplenic ligament. CLINICAL CONSIDERATIONS: VASCULAR / LYMPH SUPPLY: Splenic Artery and Splenic Vein cme int the hilus. THE DUODENUM DEVELOPMENT: Dudenum is the dividing pint between the fregut and midgut. It frms in respnse t the rtatin f the stmach. LOCATION: It is retrperitneal. (The first prtin is actually intraperitneal, but we wn't cunt that). Umbilical Regin, and Medial parts f the Left and Right upper quadrants. EXTERNAL MORPHOLOGY: It is a C-Shaped prtin f the gut. Dudenal Bulb (I) (fregut) (at abut the level f LV1 -- the transpylric plane) Hepatdudenal Ligament: There is a ligament which is part f lesser mentum. This ligament is the sign f peritneum surrunding the dudenum, hence we will cnsider the whle dudenum as retrperitneal. Descending Dudenum (II) (fregut) (LV2) Hrizntal Dudenum (III) (midgut) (LV3) Ascending Dudenum (IV) (midgut) (LV2-3) Ligament f Treitz: Attaches the furth part f the dudenum t the right crus f the diaphragm. It ges psterir t the pancreas. Essentially attaches dudenum t psterir wall. It is the Suspensry Muscle f the Dudenum -- functin t hld dudenum pened / clsed fr passage f fd int Jejunum. 10

11 INTERNAL MORPHOLOGY: Dudenal Bulb is smth internally, while the rest f it is rugh with mucsal flds. Plicae Circulares: The name f the flds n the distal three parts f dudenum. Hepatpancreatic Duct: Anastmse f the cmmn bile duct and pancreatic duct nt the dudenum. It jins at the secnd part f the dudenum. Majr Papilla: The pening int the cmmn bile and pancreatic ducts. The pancreatic duct usually jins the cmmn bile duct befre it reaches the majr papilla. Minr Papilla: Anther duct pening. Ampulla (f Vater): Ductule right at the majr papilla, which hlds bile and pancreatic enzymes. RELATIONSHIPS: The pancreas lies in the internal curvature f the C-Shape. Dudenal bulb is in transpylric plane. Superir Mesenteric Artery usually passes ver the hrizntal dudenum. Renal Artery and Vein passes psterir t the ascending (furth part f) dudenum. Arta: The furth part f the dudenum lies n the Arta. Arta is psterir t dudenum. Transverse Mescln: Inferir aspect f transverse cln. It cvers the pancreas, and crsses the dudenum at the furth part (ascending, and mst medial part). Prtal Triad: Cmmn Bile Duct, Prtal Vein, Prper Hepatic Artery. They are lcated psterir t the dudenal bulb. They are within the free edge f the lesser mentum (hepatdudenal ligament). Pancreas: Within the C-Shape f the dudenum. The head f the pancreas lies psterir t the descending and hrizntal dudenum. CLINICAL CONSIDERATIONS: Dudenal Atresia: Lack f develpment f dudenum. Dudenal Stensis: Clgging f dudenum. Vmiting: Lk fr bile as a sign f where the bstructin ccurred. If there is bile, then it was the lwer dudenum (distal t dudenal papilla), if nt, then it was the prximal dudenum (prximal t papilla). Dudenal Ulcer: Psterir aspect f the dudenal bulb, if the wall is brken, hemrrhaging can ccur as it invades the gastrdudenal artery. Fur times mre prevalent than peptic ulcers. Paradudenal Hernia: The Paradudenal Recess lies just psterir t the furth part f the dudenum. A prtin f dudenum and ilium can herniate there. The inferir mesenteric vein is right there, and can be ruptured as a result. Entergastrne: Is released by dudenum t decrease the peristalsis and acidity f material cming frm stmach. Chlecystitis: Inflammatin f gall-bladder, where bile is stred. Dudenum can frm adhesins, etc., frm what was riginally chlecystitis. Referred Pain: Pain referred in dudenum is generally referred t umbilical regin, thrugh the greater thracic splanchnic nerve. VASCULAR / LYMPH SUPPLY: Supplied by bth the Celiac Artery (fregut parts) and Superir Mesenteric Artery (Midgut parts). Gastrdudenal Arteries: Cme frm the celiac trunk ultimately. Celiac Trunk > Cmmn Hepatic > Gastrdudenal. Hepatic Arteries: Prper Hepatic and Left Hepatic cme ff f the Cmmn Hepatic Artery. Superir Mesenteric Artery and Vein passes ver last half (midgut prtins) f the dudenum. 11

12 THE PANCREAS DEVELOPMENT: Starts ut with a drsal and ventral pancreatic bud n either side f the dudenum. The ventral bud rtates 180 and jins the drsal bud. The stalk t the ventral bud becmes the majr papilla The main pancreatic duct is frmed frm bth drsal and ventral buds. Annular Pancreas: The pancreatic lbes migrate arund dudenum in the wrng directin and fuse with each ther, strangling the dudenum. Can cmpletely blck r at best result in stensis f dudenum. LOCATION: Retrperitneal. Umbilical, Epigastric, and left hypchndriac regins. It traverses diagnally frm the descending (secnd) dudenum all the way ver t the spleen. EXTERNAL MORPHOLOGY: Head -- snug up against the secnd and third parts f dudenum. Lwer prtin extending inferirly frm the head is the uncinate prcess. Neck -- directly anterir t superir mesenteric artery and veins, and the prtal vein. Bdy Tail: The tail f the pancreas extends int the splenrenal ligament, assciated with the spleen. INTERNAL MORPHOLOGY: There is a main pancreatic duct running dwn the center f the rgan. RELATIONSHIPS: Als see external mrphlgy The rt f the transverse mescln runs alng the lngitudinal axis f the pancreatic, directly anterir t it. (S the transverse cln lies n tp f it). Left Adrenal Gland and Left Kidney are just psterir t the bdy and tail f the pancras. CLINICAL CONSIDERATIONS: Referred epigastric pain culd be the pancreas r the gallbladder. If the pain wraps arund the the psterir, t, then the bile duct is prbably cmpressed (stensis) which culd be mre serius than just gallbladder. Pancreatitis: causes Gallstnes can blck the majr papilla in the dudenum. This wuld cause bile t backflw int the pancreas. A stensis in the pancreatichepatic duct can cause acid chyme t backflw int the pancreas. The stnes may blck bth cmmn bile and pancreatic ducts abve, causing bth t backflw int pancreas. VASCULAR / LYMPH SUPPLY: Superir Pancreaticdudenal Arteries (Anterir and Psterir): These cme ff f the cmmn hepatic, in turn ff f the Celiac Trunk. They als anastmse with the Right Gastrepiplic. They supply the head, generally. Great Pancreatic Artery, and Inferir Pancreatic Artery, cme ff the Splenic Artery, frm the Celiac Trunk. Supplies bdy and tail. 12

13 THE LIVER DEVELOPMENT: Fregut, clsely assciated with primitive cystic and pancreatic ducts. Starts ut as the hepatic diverticulum. Hepatic Duct elngates thrughut develpment and jins with cystic duct t frm cmmn bile duct in the adult. The liver elngates int the septum transversum during develpment. It cntinues t grw int the diaphragm later, t create the bare area f the liver -- the part that has n peritneum cvering it. The mental framen is a free brder f the lesser mentum. The prtal triad travels thrugh this hle. The ventral mesentery in the embry reduces t becme the falcifrm ligament i the adult. PRENATAL CIRCULATION: The liver is basically bypassed. LOCATION: Ductus Vensus: In the embry, it cnnects the umbilical vein with the hepatic vein and inferir vena cava. It shunts bld ging thrugh the liver s that it really desn't perfuse the liver, but rather bypasses right t the inferir vena cava. Bld ging thrugh much f the embrynic prtal vein system is shunted thrugh the ductus vensus. After birth, the ductus vensus clses and its remnants becme the ligamentum vensum, the ligament n the inferir, psterir aspect f the liver. The Rund Ligament is what remains f the umbilical vein. It hangs dwn fr the falcifrm ligament. The liver is nt cvered in the area f the falcifrm ligament attachment. Highest pint is the right lbe. It rises t the 5th intercstal space. EXTERNAL MORPHOLOGY: Ligaments: Crnary Ligament: Reflectin f peritneum ff the psterir surface f the liver, with the diaphragm. A bare area is created by the reflectin f the crnary ligaments n the diaphragm. The bare area tuches the diaphragm. Right and Left Triangular Ligaments: Part f the Crnary Ligament. Frmed by the tw layers f peritneum extending laterally. Falcifrm Ligament: Liver's reflectin f peritneum with anterir wall. The primitive ventral mesentery. Rund Ligament (Ligamentum Teres Hepatis) hangs dwn frm the falcifrm ligament, n the anterir side. Ligamentum Vensum: Psterir side f liver, separating the tw lbes. It cntinues superirly (n the psterir side) all the way t the superir margin f the liver. Lbes: The tw lbes are separated by the falcifrm ligament. Left and Right Lbes: The functinal lbes f the liver, demarcated by an imaginary line ging between the inferir vena cava (superir part) and the gall bladder (inferir part). The right lbe is the larger lbe, extending superirly t the fifth ICS when supine. The left lbe is the smaller lbe. Caudate and Quadrate Lbes: Bth n the psterir side, surrunding the prta hepatis (i.e. prtal triad). Caudate Lbe is directly superir t the prta hepatis. Part f the functinal left lbe f the liver. It is clsest t the vena cava. Quadrate lbe is directly inferir t the prta hepatis, als part f the left lbe f the liver. It is clsest t the gall bladder. Peritneal Reflectins Subphrenic Recess: Recess created by crnary ligament reflecting ff the diaphragm. Hepatrenal Recess: Recess between the right lbe f the liver and right kidney. Surfaces: Diaphragmatic Surface: The surface f the liver facing the diaphragm. Smth. Visceral Surface: The psterir and left surfaces facing the stmach, dudenum, gall bladder, and pancreas. 13

14 INTERNAL MORPHOLOGY: Prta Hepatis: The hle ging thrugh the psterir side f the right lbe, cntaining the prtal triad f vessels: Prtal Vein Cmmn Bile Duct Prper Hepatic Artery. Difference between functinal (surgical) and anatmical lbes: anatmic lbes are divided by the falcifrm ligament. Functinal lbes (as abve) are divided by the imaginary line between the gall bladder and IVC. Each functinal lbe is supplied by different vessels. RELATIONSHIPS: Inferir Vena Cava: Ges ver the reflectin f the crnary ligament, thrugh the bare area, n the superir psterir aspect f the liver. CLINICAL CONSIDERATIONS: Subphrenic Recess: Air can cllect in there as a result f surgeries. Hepatrenal Recess: This is the lwest area fr fluid t cllect in the upper abdminal cavity, when the patient is in supine psitin. DEVELOPMENT: THE GALLBLADDER LOCATION: Lcated in the gallbladder fssa f the liver, n visceral (psterir side), medial-left lbe. EXTERNAL MORPHOLOGY: A pear-shaped sac, cntaining cncentrated gallbladder bile. Small r large amunt f mesentery surrunding sac. Cmpsed f: Fundus Bdy Neck INTERNAL MORPHOLOGY: Duct system n inside is made f spiral grves. It jins the cmmn hepatic duct t frm the cmmn bile duct, which dumps ut n the majr papilla f the dudenum. RELATIONSHIPS: The bdy f the gall bladder is directly superir t the first part f the dudenum. It is adjacent t the Quadrate Lbe (lwer psterir lbe) f the liver. CLINICAL CONSIDERATIONS: Small r large amunts f mesentery may be present arund the sac. The mesentery cmmnly has vessels. S surgical remval f the gallbladder can cause massive hemrrhaging if a lt f mesentery is present.\ Chlecystkinin is the hrmne the stimulates the release f gallbladder bile. Biliary Clic = expansin f the gall bladder r cystic duct, resulting in pain in the right upper quadrant. Has many stretch receptrs, s it is sensitive t swelling. Hwever, it is relatively insensitive t a direct cut. 14

15 Chlecystitis: The infectin f the gall bladder. It is clinically determined by palpating alng the right cstal margin, alng the liver. This is Murphy's Sign. THE SMALL INTESTINE (JEJUNUM / ILIUM) DEVELOPMENT: Small intestine develps as a herniatin int the umbilical regin. Bwel spins 90 cunterclckwise during grwth, s that the distal end is t the left f th prximal end. Then, in the Return Phase, there is a 180 rtatin, which places the cecum just inferir the liver. Then the Cecum usually descends smewhat, but in sme peple and it desn't, and is thus termed a subhepatic cecum. Fixatin ccurs lastly: Organs becme retrperitneal secndarily. They start with peritneum surrunding them, then they implant n the psterir wall, then they lse their peritneum. At this pint, what was nce visceral peritneum is nw parietal. This secndary fixatin ccurs with all retrperitneal rgans except the rectum, which never has peritneum in the first place. LOCATION: It ccupies mst f the left upper quadrant and right lwer quadrant f the abdmen. Jejunum Mstly in the umbilical regin. EXTERNAL MORPHOLOGY: feet in length, but the mesentery hlding it is nly 4 feet lng because it is scrunched up. Jejunum Prximal t the Ileum. THE Mesentery is the peritneum surrunding the small intestine. INTERNAL MORPHOLOGY: Jejunum has many circular flds n the inside lining, in the mucsa. It has a thicker wall. The Ileum is smther and has slitary lymph fllicles (little spts) n inside lining. It has a thinner wall. RELATIONSHIPS: CLINICAL CONSIDERATIONS: Meckel's Diverticulum: A prtin f the bwel alng the Ileum that may be left ver frm develpment. Rule f Tws: In 2% f ppulatin, 2 feet frm the distal end f the Ileum, and 2 inches lng. It creates a puch which can cllect unwanted waste and materials. VASCULAR / LYMPH SUPPLY: Arteriae Rectae cme ff the superir mesenteric artery and supply the Jejunum, thrughut the Mesentery. They run perpendicular t the superir mesenteric artery. Arterial Arcades have a mre web-like pattern cming ff the Superir Mesenteric Artery, and supple the Ileum. 15

16 THE LARGE INTESTINE (COLON) DEVELOPMENT: Cecum, Ascending Cln, and Prximal 2/3 f Transverse Cln are midgut. Distal 1/3 f Transverse Cln, Splenic Flexure, Sigmid Cln, Rectum, and Prximal Anal Canal are hindgut. Clacal Membrane: At the distal end f the hindgut in the embry. Allantis: Psterir part f the ylk sac. It will becme the Urgenital Sinus and primitive urgenital system. Invasin f the Flds: Turneaux's Fld: A wedge f mesderm that invades the hindgut regin alng the midsagittal plane. At same time, lateral Rathke's Flds invade alng the frntal plane. These tw flds cme tgether such that the hindgut is separated frm the primitive urgenital sinus. Perineal Bdy: The tissue in between the tw primitive tubes frmed by the Rathke's and Turneax's Flds. It will frm the future Urgenital regin. The perineal bdy divides tw tubes, which are: Anrectal Canal Urgenital Sinus: This will be future perineum f the adult -- the regin belw the abdmen and superir t the pelvic bnes, medial t the thighs. Perineal bdy is the cmmn attachment site fr future muscles in the regin: Anal Sphincter. Muscles assciated with the pelvic and urgenital diaphragms. In females it prvides the primary supprt fr reprductive rgans. Prctdeum: Distal prtin f hindgut, still cvered by clacal membrane. The clacal membrane will eventually perfrate, resulting in the anal pening. PECTINATE LINE: The divisin f hindgut (enddermal) anal canal, and ectderm frm invaginatin f the skin. They are bth supplied by different vessels, nerves, etc. Upper Anal Canal, superir t pectinate line, is enddermal hindgut. Lwer Anal Canal, inferir t pectinate line, is ectderm. The Pectinate Line can be identified by lking fr the anal clumns, lngitudinal flds f mucsa that demarcate the upper anal canal. COLLATERAL CIRCULATION: Due t the pectinate line, there are tw alternative circulatins in the area. Caval System f vessels supplies the ectdermal lwer anus: Rectal Veins > Iliac Veins > Caval System Prtal System s vessels supplies the enddermal upper anus: Superir Rectal Veins > Inferir Mesenteric Vein > Prtal Vein System Because f the anastmsis, if there is an cclusin in ne system, bld can get back t the circulatin via the cllateral system. LOCATION: All fur quadrants. In the nine-regin system, it is lcated in the bttm six regins -- nt the epigastric / hypchndriac regins. EXTERNAL MORPHOLOGY: Order f Sectins: Cecum / Ilececal Junctin: Intraperitneal, fr the mst part. Vermifrm Appendix: Can be intraperitneal r retr. The appendix extends dwn ver the pelvic brim. Ascending Cln: Retrperitneal. Transverse cln: Intraperitneal, cvered by transverse mescln. Hence it is mbile. Descending Cln: Retrperitneal Sigmid Cln: Intraperitneal, cvered by sigmid mescln. Hence it is mbile. Tenia Cli: Three lngitudinal muscles that run the length f the large intestine. Rectsigmid Junctin: A cmplete expansin f the lngitudinal muscles at the end f the cln, where it can have a muscular frce. Sulci: Peridic indentatins in the large intestine, n the external surface. 16

17 Haustra: The "sectins" f intestine created by the semilunar flds. Epiplic Appendices: The fatty appendages alng the length f the large bwel. Their presence r absence is related t the diet f the individual. INTERNAL MORPHOLOGY: There are n mucsal flding, like the small intestine. There are semilunar flds, the internal markings f the sulci n the utside. They are much further apart than in the jejunum. Diverticula: Outpcketings f the bwel, at the lcatin f the semilunar flds. Fd and ppcrn can get stuck in there. RELATIONSHIPS: Transverse Mescln: The mesentery cnnecting the transverse cln t the pancreas, stmach, and dudenum. Transverse mescln cvers the pancreas. Hence pancreatitis can spread t the transverse cln. Sigmid Mescln: The mesentery cnnecting the sigmid cln t the psterir abdminal wall. Hepatic Flexure: Turning pint f the ascending > transverse cln n the right side, just inferir t the liver. Splenic Flexure: Turning pint f the transverse > descending cln n the left side, just anterir t the left kidney. Phrenicclic Ligament: Attaches the transverse cln t the left crus f the diaphragm, at the lcatin f the splenic flexure. It is right next t the spleen. It inhibits the passage f fluid int the left paraclic gutter, and prevents fluid frm getting int the supraclic (abve mescln) area. CLINICAL CONSIDERATIONS: Pancreatitis can spread t the transverse cln, via the transverse mescln. Diverticula can cause prblems. See ppcrn. Vlvulus: is twisting f the sigmid cln. It can lead t a strangulatin f the vessels and eventual necrsis. VASCULAR / LYMPH SUPPLY: Clic arteries have variatins. Right Clic Artery: Cmes ff f the superir mesenteric artery, superir t the ileclic artery, and supplies the ascending cln. It divides int the Arterial Arcades Middle Clic Artery: Cmes ff the superir mesenteric artery and supplies the Transverse Cln. It divides ff right anterir t the dudenum. Left Clic Artery: Cmes ff the inferir mesenteric artery and supplies the descending clic. Sigmid Arteries: Cme ff the inferir mesenteric and supply the sigmid cln. Abdminal Arta: THE ABDOMINAL VASCULATURE 17 Enters the Artic Hiatus between the right crus and left crus f the diaphragm at the level f T12. Extends retrperitneally alng the anterir surface f the vertebrae (slightly t the left), until the level f L4. Bifurcatin f the Abdminal Arta: It bifurcates at L4, int the Left Cmmn Iliac and Right Cmmn Iliac Arteries. RELATIONS: Ges psterir t the Uncinate Prcess and Bdy f the pancreas. Ges psterir t the hrizntal (third prtin f) dudenum. Ges psterir t the Left Renal Vein. The left renal vein passes ver (anterir t) the Arta.

18 The left renal vein passes under (psterir t) the superir mesenteric artery. The Inferir Vena Cava is t the right and slightly mre anterir than the abdminal arta. At the bifurcatin, the inferir vena cava passes psterir t the Arta. Principle Branches: Celiac Trunk Superir Mesenteric Artery Inferir Mesenteric Artery Renal Arteries Gnadal Arteries -- gnadal arteries pass t a regin in the upper abdmen, nt lwer. Celiac Trunk: Lcated just inferir t Artic Hiatus. Branches: Splenic Splenic > Left Gastrepiplic Cmmn Hepatic Cmmn Hepatic > Prper Hepatic > Gastrdudenal > Right Gastrepiplic. Right Gastrepiplic > Gastrdudenal Arteries Right Gastrepiplic > Superir Pancreaticdudenal Arteries Left Gastric Superir Mesenteric Artery: CLINICAL: If the left gastric is ccluded, bld can be reruted thrugh the right gastric. With gastresphageal cancer, the left gastric can be ligated, and the right gastric will still supply bld. Branches: SMA > Inferir Pancreaticdudenal Arteries SMA > Middle Clic > (transverse cln) SMA > Right Clic > (ascending cln) SMA > Ileclic > Ileal and Clic Marginal Artery: Cmes ff the Left Clic Artery and can supply the medial aspect f the large intestine in the absence f a middle clic. Inferir Mesenteric Artery: IMA > Left Clic IMA > Sigmid Artery IMA > Rectsigmid IMA > Superir Rectal Pancreaticdudenal Arcade: An alternative rute fr bld flw thrugh the branches f the celiac, if there shuld be an cclusin in the celiac trunk. Superir Pancreaticdudenal Arteries cme frm the Hepatic branch f the Celiac. Inferir Pancreaticdudenal Arteries cme frm the SMA. Lumbar Arteries: Supply the psterir abdminal wall. 1st - 4th Lumbar Arteries cme ff f the Artic Trunk directly. 5th Lumbar Artery cmes ff f the Median Sacral Artery, belw the bifurcatin f the Arta. PORTAL VENOUS SYSTEM: Takes bld frm the entire abdmen and dumps it int the liver fr prcessing > ut the Suprahepatic Inferir Vena Cava. Abdminal venus drainage ends in the hepatic sinusids in the liver. 18

19 Apprx 67% f the liver's bld is venus bld frm the prtal vein. The ther 33% cmes frm the hepatic arteries. BLOOD IN THE LIVER: Venus Bld Ging int the liver: prtal vein branches t left prtal vein and right prtal vein, t g t the respective functinal lbes f the liver. Then it further subdivides until it gets t the hepatic sinusids. Venus bld leaving the liver: Central Vein > Sublbar Veins > Left and right Hepatic Veins > Inferir Vena Cava. BRANCHES Bld ging t the prtal vein: The anastmse f the splenic vein and superir mesenteric vein. Inferir Mesenteric Vein: Jins with the Splenic Vein, 60% f the time, and with the Superir Mesenteric Vein, 40% f the time. RELATIONS Right at the anastmses f SMV and Splenic Vein, the prtal vein passes psterir t the neck f the pancreas. (CLINICAL) Hence tumrs in the head and neck f the pancreas can cclude the prtal vein. Passes psterir t the cmmn hepatic artery, just suth f the liver. PORTAL TRIAD: Duh. Prtal Vein, Prper Hepatic Artery, and Cmmn Bile Duct, ging thrugh the Prta Hepatis n the psterir side f the liver, between the caudate and quadrate lbes. PORTAL HYPERTENSION: Increased bld flw in hepatic prtal system, creating increased pressure in the rest f the venus system. Occlusin can be prehepatic, intrahepatic, r psthepatic, depending n where the cclusin ccurs. THE PORTAL VENUS SYSTEM DOES NOT HAVE VALVES. Because the prtal system has n valves, the bld can flw back n itself, causing an increase in pressure. Bld tries t get back t the heart and winds up taking cllateral channels, which creates a dilatin utside the prtal system, causing varicse veins. (this is nly ne cause f varicse veins). CAPUT MEDUSAE: Varicsity f the paraumbilical veins, due t severe prtal hypertensin. They lk like smewhat like small snakes n the skin. They radiate in a wheel-like fashin. Ascites: Increased fluid in the peritneal cavity. Can result frm the liver's inability t handle increased bld pressure. Hemrrhids: Varicse veins in the anal regins. COUGH UP BLOOD: Bld backflw int esphageal plexus culd make yu cugh up (r vmit) bld frm prtal hypertensin. Imprtant clinical diagnstic sign. COLLATERAL VENOUS PATHWAYS: In the event f prtal hypertensin r prtal stensis. Paraumbilical Pathway: The paraumbilical vein feeds int the prtal vein, in the left lbe the liver. These are usually clsed ff after birth, but in the event f prtal hypertensin, they can recanalize. Umbilical Veins (recanalized) > Inferir Epigastric Veins > Superficial Epigastric Veins > IVA / SVC. Esphageal Pathway: Bld back flws int the left gastric and eventually makes its way back t the azygs vein. Left Gastric Vein > Esphageal Vein (plexus) > Inferir Thyrid Veins (ne n each side) > Azygs system f veins Caval/Prtal Pathway: At the pectinate line is anther cllateral pathway. Upper prtin f anal canal drains via Superir Rectal Vein > IMV Lwer Prtin f anal canal drains via MIddle and Inferir Rectal Veins > Caval System. PECTINATE LINE: The tw venus systems anastmse with each ther, s backflw can take the alternative rute at that lcatin. HEMORRHOIDS: INTERNAL HEMORRHOIDS: Hemrrhids in the upper anal canal caused by varicsities f the superir rectal vein. They are innervated by autnmic nerves and hence are nt painful. EXTERNAL HEMORRHOIDS: Varicsities f the inferir and middle rectal veins. They are innervated by smatic nerves and are painful. 19

20 THE NERVOUS SYSTEM CNS: The brain and the spinal chrd. Peripheral Nervus System: All ther nerves, cnsisting f the Autnmic Nervus System (ANS) and Smatic Nervus System (SNS). Autnmic Nervus System: Invluntary innervatin f visceral structures. Innervates smth (invluntary) muscle, cardiac muscle, and glands. GVE: General Visceral Efferent -- Respnsible fr mtr functin t visceral tissues. "Efferent" refers t flw frm CNS t tissues, s that they will stimulate r effect a respnse. GVA: General Visceral Afferent -- respnsible fr sensry functin frm visceral tissues. "Afferent" refers t flw frm the tissues back t the CNS, s they carry the impulse away frm the stimulus. These are made up primarily f stretch receptrs, s that inflammatin r distensin f rgans can be sensed. Smatic Nervus System: Vluntary innervatin f smatic structures (skeletal muscles and skin). GSE: General Smatic Efferent -- respnsible fr mtr functin t smatic tissues. GSA: General Smatic Afferent -- respnsible fr sensry functin frm smatic tissues. Types f Nerves fibers: There are many types f nerve fibers in a single nerve bundle. Mtr Fibers Sensry Fibers Pain receptrs -- riginating frm smatic structures. Temperature -- riginate frm smatic structures. Stretch receptrs -- riginating frm visceral structures. These are imprtant t visceral structures, as they cnstitute the main sensry input frm the rgans. MIXED NERVE: Nerves such as vagus and phrenic carry bth afferent and efferent fib3ers, and bth smatic and autnmic. Therefre they are mixed nerves. REFERRED PAIN: The interpretatin f dermatmal layers in the brain is respnsible fr the cncept f referred pain. Sensry input frm the visceral rgans is interpreted by the brain as riginating frm ne f the dermatmal segments. The brain versimplifies the stimulus as cming frm a cutaneus layer. Take Appendicitis as an example: Inflamed appendix sends an impulse t T10, which is then sent t brain t be prcessed. Umbilical cutaneus dermatmal regin als ges t T10, and in the past the brain has received mre inf frm this regin, s it "assumes" that the appendix signal is cming frm such a regin. S, there is an initial referred dull (visceral) pain in the umbilical regin. Then if the appendix inflames enugh t pierce r press against the anterir wall, it will stimulate pain-afferent nerves in the lwer right quadrant, s that will create a sharp (smatic) pain in the regin f the appendix. These tw signs tgether culd be taken as signs f appendicitis. STRUCTURE OF PARAVERTEBRAL GANGLIA: 20 Drsal Rt Ganglin: They have afferent (incming sensry) nerves. Tw afferent nerves cme in -- ne frm the peripheral tissues and ne frm the central canal. Ventral Rt Ganglin: Carries efferent fibers ut t the periphery. Spinal Nerves frm where these tw rts cme tgether, t frm bth sensry and mtr fibers in the same nerve. All spinal nerves are mixed nerves! Sn after frming, the spinal nerve divides int tw nerves -- the pre-ganglinic nerves. drsal primary ramus -- innervates muscles and skin f back. ventral primary ramus -- innervates lateral and anterir. Ventral Primary Ramus ges t the White Rami Cmmunicans n the sympathetic chain. S the White Rami carries the efferent pre-ganglinic nerves.

21 Once the nerve-fiber reaches the sympathetic trunk, it has several ptins: It can synapse with a Grey Rami Cmmunicans and cntinue as a sympathetic spinal nerve ging ut t target viscera. It can ascend t a higher level in the sympathetic chain. It can descend t a lwer level in the sympathetic chain. It can pass thrugh and ut f the paravertebral ganglin withut synapsing, and then cntinue nt a target rgan as a splanchnic nerve -- t g t visceral target rgan and frm a visceral plexus -- r branch smewhere nearby, like celiac r superir mesenteric arteries. SYMPATHETIC PARASYMPATHETIC Spinal Chrd Origin Thraclumbar: T5-T12, L1-L2 Cranisacral: C10 (Vagus Nerve), S2-S4. Effects Widespread, lw precisin Specific, discrete, lcal, acute. Lcatin f cell bdies Alng the spinal chrd, at the sympathetic chain ganglia. Plexuses are fund alng the midline f the bdy -- pre-artic ganglia, mesenteric plexuses. Adjacent t r in the target rgan. Pre-Ganglinic Fiber Shrt Lng Pst-Ganglinic Fiber Lng Shrt Pre-Ganglin : Pst-Ganglin fiber rati Neurtransmitter General energy use and metablism Lw rati -- ne pre-ganglin spreads t lts f pst-ganglin, hence the effect is widespread and imprecise Acetylchline at pre-synapse terminals Nrepinephrine at pst-synapse terminals Fight r flight -- expenditure f energy. High Rati -- 1:1 r near 1:1, hence the effect is mre lcalized. Acetylchline Intake and cnservatin f energy The Vagus Nerve: Fregut and Midgut innervatin In the thrax, the right vagus runs psterir t the esphagus, and the left vagus runs anterir t it. Arund the esphageal hiatus (T10), the tw vagus nerves mix, and then they separate again, t frm the right and left vagal trunks. Left (Anterir) Vagal Trunk: Gives ff Hepatic Branch and Principle Anterir Gastric Branch. Right (Psterir) Trunk: Frms the Celiac Plexus > Superir Mesenteric Plexus. These nerves are perivascular -- they fllw the curse f the arteries. Pelvic Splanchnic Nerves: Hindgut innervatin The Pelvic Splanchnic Nerves are parasympathetic Sacral spinal nerves S2-S4. They frm Pelvic Plexuses > Inferir Hypgastric Plexus > Pelvic viscera, and separately, the hindgut. These nerves are Nn-Perivascular. They d nt fllw the arteries, but instead crisscrss the arteries. The nerves are still lcated in mesentery. The lwer anus (belw pectinate line) is innervated by smatic nerves -- the pudendal nerve -- nt parasympathetic pelvic splanchnic. Greater Thracic Splanchnics: T6-T9. Sympathetic spinal nerves supplying the fregut and midgut. 21