Week 5 11-21.pdf

Inguinal Canal oblique passage, about 4 cm in length, through lower part of anterior abdominal wall lies parallel and immediately above medial part of inguinal ligament contents: males-spermatic cord (formed by structures running bet...

Inguinal Canal oblique passage, about 4 cm in length, through lower part of anterior abdominal wall lies parallel and immediately above medial part of inguinal ligament contents: males-spermatic cord (formed by structures running between testis and abdominopelvic cavity) and ilioinguinal nerve females- round ligament of uterus (fibrous cord that extends from uterus to labium majus), genital branch of genitofemoral nerve and ilioinguinal nerve in males, genital branch of genitofemoral nerve is part of spermatic cord openings: deep inguinal ring (opening in transversalis fascia) located approximately halfway between ASIS and pubic tubercle (inferior epigastric vessels pass medial to deep inguinal ring) superficial inguinal ring (opening in aponeurosis of external oblique) located immediately superior to pubic tubercle walls: (Netter’s Plate 263) anterior: aponeurosis of external oblique posterior: transversalis fascia inferior: inguinal ligament superior: lower borders of internal oblique and transversus abdominis https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 18 of 38  Abdominal Hernia protrusion of abdominal contents beyond normal confines of abdominal wall - has 3 parts: hernial sac, contents of sac and coverings of sac sac: pouch (diverticulum) of parietal peritoneum contents: may consist of any structure found within abdominal cavity (piece of omentum, loop of small intestine, etc.) coverings: formed by layers of abdominal wall through which hernial sac passes there are various types of abdominal hernias (inguinal, femoral, umbilical, incisional, etc.) approximately 75% of abdominal hernias occur in inguinal region (most common type of abdominal hernia) inguinal hernias occur more often in males than females Types of Inguinal Hernias https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 20 of 38  Indirect Inguinal Hernia most common type of inguinal hernia (⅔ to ¾ inguinal hernias are indirect) hernial sac leaves abdominal cavity lateral to inferior epigastric vessels, through deep inguinal ring à neck of hernial sac is narrow results from a persistent processus vaginalis (outpouching of peritoneum that in the fetus is responsible for formation of inguinal canal) à considered to be congenital in origin more common in children and young adults https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 21 of 38  Direct Inguinal Hernia hernial sac leaves abdominal cavity medial to inferior epigastric vessels hernial sac protrudes through an area of relative weakness in posterior wall of inguinal canal inguinal (Hesselbach’s) triangle is bounded by inferior epigastric vessels (laterally), rectus abdominis (medially) and inguinal ligament (inferiorly). the neck of hernia sac is wide https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 22 of 38  Intraperitoneal and Retroperitoneal Relationships terms used to describe relationship of abdominal organs to their peritoneal coverings intraperitoneal organ -organ that is almost totally covered with peritoneum ( ex.: stomach, jejunum, ileum, transverse colon, sigmoid colon, spleen) retroperitoneal organ- organ that is located posterior to peritoneal sac (between peritoneal sac and posterior abdominal wall) organ is only covered with peritoneum anteriorly (ex.: most of duodenum and pancreas, ascending colon, descending colon, kidneys, suprarenal glands, abdominal aorta, IVC) Peritoneal Folds ligament: two-layered peritoneal fold that connects an organ (usually a solid organ) to abdominal wall or another organ- does not consist of dense fibrous connective tissue like ligaments associated with joints some examples: Falciform ligament- peritoneal fold that connects liver to anterior abdominal wall (above umbilicus) coronary ligament- peritoneal fold that connects liver to diaphragm splenorenal ligament -peritoneal fold that connects spleen to left kidney -gastrosplenic ligament- peritoneal fold that connects spleen to stomach https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 25 of 38  omentum: peritoneal fold that passes from stomach and proximal part of duodenum to another organ lesser omentum- two-layered peritoneal fold that connects lesser curvature of stomach and 1st part of duodenum to visceral (inferior) surface of liver has 2 parts: hepatogastric and hepatoduodenal ligaments hepatogastric ligament is thin hepatoduodenal ligament forms right margin of lesser omentum and is thick because it contains ducts, blood vessels, lymph vessels and nerves traveling to and from liver greater omentum- hangs down from greater curvature of stomach, like an “apron”, in front of loops of jejunum and ileum. It contains a variable amount of fat and consists of 4 peritoneal layers (2 anterior layers descend from greater curvature of stomach, fold back on themselves and ascend (becoming 2 posterior layers) to attach to transverse colon. The space between 2 anterior and 2 posterior layers is obliterated. Key relationship: The greater omentum attaches the stomach to the transverse colon. The transverse mesocolon attaches the transverse colon to the posterior abdominal wall. https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 28 of 38  mesentery: two-layered peritoneal fold that connects intestines to posterior abdominal wall that allows blood vessels, lymph vessels and nerves to reach intestines from posterior abdominal wall parts of intestines that have mesentery are more mobile and are intraperitoneal. examples: mesentery of small intestine (or just simply “the mesentery”) à connects loops of jejunum and ileum to posterior abdominal wall transverse mesocolon (mesentery of transverse colon) à connects transverse colon to posterior abdominal wall sigmoid mesocolon (mesentery of sigmoid colon) à connects sigmoid colon to posterior abdominal and pelvic walls mesenteries have a root posterior border of mesentery attached to posterior abdominal wall https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 30 of 38  Secondary Retroperitoneal Organs early in development, all parts of digestive tract are intraperitoneal and have a mesentery with further development, some parts of digestive tract adhere to posterior abdominal wall, loose their mesentery and become retroperitoneal (more fixed in position) à they are known as secondary retroperitoneal organs (ex. most of duodenum, most of pancreas, ascending colon, descending colon) Lesser Sac (Omental Bursa) part of peritoneal cavity located posterior to lesser omentum and stomach (all remaining peritoneal cavity is referred to as “greater sac”) superior recess: upward extension of lesser sac, located between liver and diaphragm inferior recess: downward extension of lesser sac between 2 anterior and 2 posterior layers of greater omentum (usually very short due to adherence of anterior and posterior layers of greater omentum) on the left it is closed by spleen, gastrosplenic ligament and splenorenal ligament on the right it communicates with greater sac via omental (epiploic) foramen (a.k.a. opening of lesser sac, foramen of Winslow) Epiploic (Omental) Foramen (Opening of Lesser Sac, Foramen of Winslow) boundaries: anteriorly: right, free border of lesser omentum (hepatoduodenal ligament), within which are structures traveling to and from liver (3 main structures: portal vein, proper hepatic artery and common bile duct) posteriorly: inferior vena cava superiorly: caudate lobe of liver inferiorly: 1st part of duodenum https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 32 of 38  Peritoneal Folds in the Lower Part of the Anterior Abdominal Wall 1 median umbilical fold-formed by peritoneum that covers median umbilical ligament (fibrous cord that extends from apex of urinary bladder to umbilicus) à it is a remnant of allantois of embryo (when lumen of allantois obliterates in the embryo, it is called urachus; in the adult it is known as median umbilical ligament) 2 medial umbilical folds (1 on each side) - formed by peritoneum that covers medial umbilical ligaments à fibrous cords that represent distal, obliterated parts of umbilical arteries 2 lateral umbilical folds (1 on each side) -formed by peritoneum that covers inferior epigastric vessels https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 34 of 38  Other Subdivisions of the Abdominal Cavity transverse colon and its mesentery (transverse mesocolon) divide abdominal cavity into supracolic and infracolic compartments supracolic compartment: located above transverse colon and its mesentery- contains stomach, liver, gallbladder, spleen infracolic compartment:l ocated below transverse colon and its mesentery - contains most of the small and large intestines à divided into right and left infracolic spaces by mesentery of small intestine there is free communication between supracolic and infracolic compartments via paracolic gutters (grooves between lateral aspects of ascending and descending colon and abdominal wall) https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 36 of 38  Nerve Supply of the Peritoneum parietal peritoneum: peritoneum that covers central part of undersurface of diaphragm is innervated by phrenic nerves (pain referred to shoulder) peritoneum that covers peripheral part of undersurface of diaphragm is innervated by lower 5 intercostal nerves and subcostal nerve remaining of parietal peritoneum is innervated by lower 5 intercostal nerves, subcostal nerve and iliohypogastric and ilioinguinal nerves visceral peritoneum is innervated by visceral sensory fibers that travel with sympathetic and parasympathetic fibers that supply organs pain originating from parietal peritoneum is usually more intense and well localized pain originating from visceral peritoneum is usually dull and poorly localized (referred pain) https://sites.google.com/view/grossanatomyii/week-5-lecture-notes 6/21/24, 1:34 PM Page 38 of 38