Abdomen

 

 

·          Superficial fascia of Anterior Abdominal Wall

1. Superficial layer of the superficial fascia (Camper's fascia) Continues over the inguinal ligament to merge with the superficial fascia of the thigh.Continues over the pubis and perineum as the superficial layer of the superficial perineal fascia.

2. Deep layer of the superficial fascia (Scarpa's fascia) is attached to the fascia lata just below the inguinal ligament.Continues over the pubis and perineum as the membranous layer (Colles' fascia) of the superficial perineal fascia.

Continues over the penis as the superficial fascia of the penis and over the scrotum as the tunica dartos, which contains smooth muscle.

May contain extravasated urine between this fascia and the deep fascia of the abdomen, resulting from rupture of the spongy urethra.

Deep fascia Covers the muscles and continues over the spermatic cord at the superficial inguinal ring as the external spermatic fascia.

Continues over the penis as the deep fascia of the penis (Buck's fascia) and over the pubis and perineum as the deep perineal fascia.

·         Iliopectineal arcus or ligament is a fascial partition that separates the muscular (lateral) and vascular (medial) lacunae deep to the inguinal ligament.

The muscular lacuna transmits the iliopsoas muscle.

The vascular lacuna transmits the femoral sheath and its contents, including the femoral vessels, a femoral branch of the genitofemoral nerve, and the femoral canal.

·         Indirect inguinal hernia is found more commonly on the right side in men and is more common than direct inguinal hernia. It is congenital (present at birth), associated with the persistence of the processus vaginalis, and covered by the peritoneum and the coverings of the spermatic cord.

·         Spermatic cord has several fasciae:

External spermatic fascia, derived from the aponeurosis of the external oblique muscle.

Cremasteric fascia (cremaster muscle and fascia), originating in the internal oblique muscle.

Internal spermatic fascia, derived from the transversalis fascia.

ICE = TIE

Clinical: Indirect Inguinal Hernia has all the covering of Spermatic Cord.

Whereas Direct Inguinal Hernia is b/w Ext Spm Fascia & Cremasteric fascia.

Bith Hernia emerge through Sup Ing Ring, but only Indirect also come out through Deep Ing Ring.

·         Gubernaculum testis is homologous to the ovarian ligament and the round ligament of the uterus.

·         Inferior epigastric artery arises from the external iliac artery above the inguinal ligament, enters the rectus sheath, and ascends between the rectus abdominis and the posterior layer of the rectus sheath.

Anastomoses with the superior epigastric artery, providing collateral circulation between the subclavian and external iliac arteries.

·         Lesser omentum Acts as a route for the left and right gastric vessels, which run between its two layers along the lesser curvature.

·         Greater omentum transmits the right and left gastroepiploic vessels along the greater curvature.

·         Gastric ulcers may perforate into the lesser sac and erode the pancreas and the splenic artery, causing fatal hemorrhage. Duodenal ulcers may erode the pancreas or the gastroduodenal artery, causing burning and cramping epigastric pain, and are three times more common than gastric ulcers.

·         FYI : Duodenum is the WIDEST part of S.I.

·         Duodenojejunal junction is fixed in position by the suspensory ligament of Treitz, a surgical landmark. This fibromuscular band is attached to the right crus of the diaphragm.

·         FYI : The ileocecal fold is the bloodless fold of Treves (surgeon at the London Hospital who drained the appendix abscess of King Edward VII in 1902).

·         The quadrate lobe receives blood from the left hepatic artery and drains bile into the left hepatic duct, whereas the caudate lobe receives blood from the right and left hepatic arteries and drains bile into both right and left hepatic ducts.

CAUDATE LOBE is Medical Superior and QUADRATE LOBE is Medical Inferior in Left Lobe. Thus keep in MIND that CAUDATE is not Caudal here.

Liver: side with ligamentum venosum/ caudate lobe vs. side with quadrate lobe/ ligamentum teres "VC goes with VC": The Venosum and Caudate is on same side as Vena Cava [posterior]. Therefore, quadrate and teres must be on anterior by default.

·         Pringle's maneuver: is a temporary cross-clamping (intermittent soft vascular clamping) of the hepatoduodenal ligament containing portal triads at the foramen of Winslow for control of hepatic bleeding during liver surgery or donor hepatectomy for living liver transplantation.

·         Superior rectal artery is the termination of the inferior mesenteric artery, descends into the pelvis, divides into two branches that follow the sides of the rectum, and anastomoses with the middle and inferior rectal arteries. The middle and inferior rectal arteries arise from the internal iliac and internal pudendal arteries, respectively.

·         superior suprarenal artery from the inferior phrenic artery, the middle suprarenal artery from the abdominal aorta, and the inferior suprarenal artery from the renal artery.

·         PORTAL VEIN is formed by the union of the splenic vein and the superior mesenteric vein posterior to the neck of the pancreas. The inferior mesenteric vein joins either the splenic or the superior mesenteric vein or the junction of these two vein.

·         Two pelvic kidneys may fuse to form a solid lobed organ because of fusion of the renal anlagen, called a cake (rosette) kidney.

·         Nephroptosis: is downward displacement of the kidney, dropped kidney, or floating kidney caused by loss of supporting fat. The kidney moves freely in the abdomen and even into the pelvis. It may cause a kink in the ureter or compression of the ureter by an aberrant inferior polar artery, resulting in hydronephrosis.

·         Aorta bifurcates at L4.

IVC starts at L5.

·         Para-aortic bodies (Zuckerkandl's bodies) are small masses of chromaffin cells found near the sympathetic chain ganglia along the abdominal aorta and serve as chemoreceptors responsive to lack of oxygen, excess of carbon dioxide, and increased hydrogen ion concentration that help to control respiration.

·         Solar plexus: is the combined nerve plexus of the celiac and superior mesenteric plexuses.

·          Apertures through the diaphragm

1. Vena caval hiatus (vena caval foramen)

Lies in the central tendon of the diaphragm at the level of T8 and transmits the IVC and occasionally the right phrenic nerve.

2. Esophageal hiatus

Lies in the muscular part of the diaphragm (right crus) at the level of T10 and transmits the esophagus and anterior and posterior trunks of the vagus nerves.

3. Aortic hiatus

Lies behind or between two crura at the level of T12 and transmits the aorta, thoracic duct, azygos vein, and occasionally greater splanchnic nerve.

·         Portal-systemic anastomoses

1. Left gastric → azygous (esophageal varices)

2. Superior → inferior rectal (external hemorrhoids)

3. Paraumbilical → inferior epigastric (caput medusae at navel)

4. Retroperitoneal → renal

5. Retroperitoneal → Paravertebral

Varices of gut, butt, and caput are commonly seen with portal hypertension.

·         COUINAUD'S CLASSIFICATION

it divides liver into 8 segments principally on the position of 3 hepatic veins and the main portal veins

segment 1- caudate lobe

segment 2 and 3- lateral segment of left lobe

segment 4- medial segment of the left lobe

segment 5 and 8- anterior segment of right lobe

segment 6 and 7- posterior segment of the right lobe

·         Aganglionic megacolon (Hirschsprung's disease) is caused by the absence of enteric ganglia parasympathetic postganglionic neuron cell bodies) in the lower part of the colon.

·         The right and left hepatic veins drain into the inferior vena cava. The right gastroepiploic vein drains into the superior mesenteric vein, but the left one drains into the splenic vein. The right gonadal and suprarenal veins drain into the inferior vena cava, whereas the left ones drain into the left renal vein. The right colic vein ends in the superior mesenteric vein, but the left one terminates in the inferior mesenteric vein.

·         Pain sensation originating from peritoneal irritation by gastric contents in the lesser sac is carried by lower intercostals nerves. The vagus nerves carry sensory fibers associated with reflexes in the gastrointestinal (GI) tract. The greater splanchnic nerves and white rami communicantes carry pain (general visceral afferent [GVA]) fibers from the wall of the stomach and other areas of the GI tract. The gray rami communicantes contains no sensory fibers but contain sympathetic postganglionic fibers.

·         The efferent limb of the reflex arc is the genital branch of the genitofemoral nerve, whereas the afferent limb is the femoral branch of the genitofemoral nerve.

·         The left gastroepiploic artery runs through the lienogastric ligament. The splenic artery is found in the lienorenal ligament. The right and left gastric arteries run within the lesser omentum. The gastroduodenal artery descends between the duodenum and the head of the pancreas.

·         The left colic vein is a tributary of the inferior mesenteric vein. The middle colic, inferior pancreaticoduodenal, and ileocolic veins drain into the superior mesenteric vein. The left gastroepiploic vein empties into the splenic vein.

·         The superficial inguinal lymph nodes receive lymph from the scrotum, penis, buttocks, and lower part of the anal canal, and their efferent vessels enter primarily to the external iliac nodes and ultimately to the lumbar (aortic) nodes. The deep inguinal nodes receive lymph from the testis and upper parts of the vagina and anal canal, and their efferent vessels enter the external iliac nodes.

·         The genitofemoral nerve descends on the anterior surface of the psoas muscle and gives rise to a genital branch, which enters the inguinal canal through the deep inguinal ring to supply the cremaster muscle, and a femoral branch, which supplies the skin of the femoral triangle. The genitofemoral nerve is not a branch of the femoral nerve but arises from the lumbar plexus and does not supply the testis. It is the ilioinguinal nerve that gives rise to an anterior scrotal branch.

·         The third part of the duodenum (transverse portion) crosses anterior to the inferior vena cava.

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