Abdomen in General (V1) - Anatomy Lecture Notes PDF

ANATOMY | TRANS #1 LE Abdomen in General MA. JENINA ANGELA ESGUERRA-PACULAN, M.D. (01/15/2024) | Version 1...

ANATOMY | TRANS #1 LE Abdomen in General MA. JENINA ANGELA ESGUERRA-PACULAN, M.D. (01/15/2024) | Version 1 04 OUTLINE I. Overview IV. Peritoneum and Peritoneal a. Abdominal Wall Cavity b. Abdominal Cavity a. Peritoneum c. Reference Planes b. Peritoneal Cavity d. Abdominal Areas c. Embryology II. Anterolateral Abdominal Wall d. Peritoneal Formations a. Layers e. Subdivisions of the b. Muscles Peritoneal Cavity c. Rectus Sheath V. Posterior Abdominal Wall d. Neurovasculature a. Fascia e. Internal Surface b. Muscles f. Surface Anatomy c. Neurovasculature III.Inguinal Region VI. Review Questions a. Inguinal Ligament VII. References b. Iliopubic Tract VIII. Appendix c. Inguinal Canal d. Spermatic Cord, Scrotum and Testes Must Lecturer Book Previous Youtube Know Trans Video Figure 1. Differentiation of peritoneal cavity and peritoneum Anterolateral abdominal wall and several organs lying against the SUMMARY OF ABBREVIATIONS posterior wall are covered internally with a serous membrane or ASIS Anterior Superior Iliac Spine peritoneum (serosa) that reflects onto the abdominal viscera ICS Intercostal Space (e.g. stomach, intestines, liver, and spleen) IV Intervertebral Bursal sac or peritoneal cavity: IVC Inferior Vena Cava → Double-layered MCL Midclavicular Line → Forms between the walls and the viscera TFL Tensor Fascia Latae → Contains enough parietal or extracellular fluid to lubricate the membrane covering the (abdominal) structures LEARNING OBJECTIVES Functions: ✔ To discuss the anterolateral abdominal wall, specifically: ▪ Provides passage for the blood vessels, lymphatics, and o Fascia nerves o Muscles ▪ Facilitates the movements associated with digestion o Neurovasculature o Internal Surface B. ABDOMINAL CAVITY o Inguinal Region o Surface Anatomy ✔ to discuss the peritoneum and peritoneal cavity, specifically: o Embryology o Peritoneal Formations o Subdivisions of the Peritoneal Cavity ✔ To discuss the posterior abdominal wall ✔ To recall the discussion on the diaphragm and introduce some concepts in the discussion on abdominal viscera I. OVERVIEW A. ABDOMINAL WALL Abdominal wall descriptors: → Dynamic Can produce tension for rigidity but also apply specific vectors of force for precise movement and control of the trunk → Multi-layered, and musculo-aponeurotic Formed by muscles that interlace and intertwine together to form the abdominal wall Abdominal wall functions: Figure 2. Abdominopelvic cavity → Increase abdominal pressure The abdominal cavity forms the superior and major part of the → Accommodate expansion from ingestion, pregnancy, fats, or abdominopelvic cavity any pathology → Abdominopelvic cavity is a continuous cavity that extends from the thoracic diaphragm to the pelvic diaphragm Has no floor of its own; instead, the plane of the pelvic inlet (superior pelvic aperture) arbitrarily separates the abdominal and pelvic cavities The abdominal cavity extends superiorly to the fourth osseocartilaginous thoracic cartilages up to the 4th intercostal space LE 1 TG 24 | Abcede, Advincula, Acharon, Alcid, Batol, TE | Alcid, Advincula AVPAA | C. Cabuyao, C. PAGE 1 of 18 TRANS 1 Bauzon, Bertillo, Bisa, Buenaventura Cambas, M. Carating ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. Protects superiorly located organs (e.g. spleen, liver, parts of the kidneys and stomach) via its association with the thoracic cage Posteriorly, the greater pelvis partially supports the lower abdominal viscera (e.g., ileum, caecum, appendix, and sigmoid colon) C. REFERENCE PLANES For ease of description and/or localization, planes of reference are used to identify areas of the abdomen The abdomen can be delineated either into 9 regions by using 4 planes of reference, or 4 quadrants using 2 planes of reference Figure 4. Overview of viscera of thorax and abdomen showing transpyloric and interspinous planes Preferred reference planes Surgeons prefer these reference planes as an alternative to the two transverse planes previously discussed ▪ Transpyloric plane Extrapolated midway between superior borders of the manubrium of the sternum and the pubic symphysis (typically the L1 vertebral level) Commonly transects the pylorus (the distal, more tubular Figure 3. Common and preferred abdominal reference planes part of the stomach) when the patient is recumbent dividing the abdomen into 9 regions (supine or prone) (see Fig 4) Also known as Addison’s plane, surgeons prefer this Common reference planes plane as baseline because an injury in this area most These planes can be located by palpation from the surface likely means a surgery since it traverses a lot of clinically since they intersect palpable structures significant structures ▪ Two (2) sagittal planes o Fundus of the gallbladder − Midclavicular planes o Neck of the pancreas Pass from the midpoint of the clavicles (~9 cm from o Origin of the superior mesenteric artery, and the midline) to midinguinal points, midpoints of the lines hepatic portal veins joining the anterior superior iliac spine (ASIS), and o Root of the transverse mesocolon pubic tubercles on each side. It also passes just o Duodenojejunal junction lateral to the tip of the ninth costal cartilage, which is o Hila of the kidneys palpable and roughly corresponds to the lateral border ▪ Interspinous plane of the rectus abdominis muscle Passes through easily palpable ASIS on each side ▪ Two (2) transverse planes − Importance: − Transtubercular plane o Defines the lower boundary of the Spigelian hernia Passes and can be palpated through the iliac belt in hernia surgery tubercles (~5 cm posterior to the ASIS on each side) o Important consideration during the planning of the and the body of the L5 vertebra rectus abdominis myocutaneous flap/abdominoplasty the confluence of the common iliac veins (i.e. IVC origin) lie on this plane − Subcostal plane Passes through the inferior border of the 10th costal cartilage on each side o can be used to find the level of the transpyloric plane which is 1 rib (rib 9 costal cartilage) superior to it The subcostal plane also aligns with the body of L3, so by anteriorly palpating rib 10 (the inferior-most rib element) and working directly posterior from here, we will end up on the spinous process of L3 or the L2/L3 interspinous space Figure 5. Planes dividing abdominal cavity into 4 quadrants Alternatively, the abdomen can also be divided into right upper quadrant, left upper quadrant, right lower quadrant, and left lower quadrant using two planes: ANATOMY Abdomen in General PAGE 2 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. → Transumbilical plane ▪ Transversely passes through umbilicus (and the IV disc Answer: The lesion is about 1 cm, red, and flat. It is located in between the L3 and L4 vertebrae) dividing it into upper and the upper left quadrant of the stomach. lower halves → Median plane When describing pathologies, it must be simple. Just say what ▪ Passes longitudinally/vertically through the body dividing it is asked and describe and say the location. For example, into right and left halves epigastric pain - abdominal pain located in the epigastric area and then the rating of the pain. D. ABDOMINAL AREAS ABDOMINAL REGIONS Table 2. Structures found in each abdominal quadrant Right Upper Quadrant Left Upper Quadrant Pylorus of the stomach Stomach 1st-3rd part of the duodenum Jejunum Superior ascending colon Proximal ileum Hepatic flexure Left transverse colon Right transverse colon Splenic flexure Superior descending colon Gallbladder Spleen Head of the pancreas Body and tail of the pancreas Right lobe of the liver Left lobe of the liver Right suprarenal gland Left suprarenal gland Right kidney Left kidney Figure 6. Abdominal Regions Right Lower Quadrant Left Lower Quadrant Delineated by four (4) planes (see Fig. 3): Most of ileum Inferior descending colon → Two transverse/horizontal Planes: Subcostal plane and Caecum Sigmoid colon Transtubercular plane Appendix → Two sagittal/vertical planes: Left and right midclavicular planes Inferior ascending colon Left ovary The nine (9) regions are used to describe the location of Right ovary Left uterine tube abdominal organs, pains, or pathologies Right uterine tube Abdominal part of the right Table 1. Abdominal Regions Abdominal part of the right spermatic cord RH Right E Epigastric LH Left spermatic cord Abdominal part of the right Hypochondrium Hypochondrium Abdominal part of the right ureter ureter (Enlarged) uterus RL Right Lumbar/ U Umbilical LL Left Lumbar/ (Enlarged) uterus (Distended) urinary bladder Lateral/Flank Lateral/Flank (Distended) urinary bladder RI Right P Pubic/ LI Left ANTEROLATERAL ABDOMINAL WALL Iliac/Inguinal/Groin Hypogastric Iliac/Inguinal/Groi n *Refer to Figure 6 ABDOMINAL QUADRANTS Used for general localization as opposed to abdominal regions, which are used for more specific localization Delineated by: Umbilical plane and Median plane forming the left upper quadrant, right upper quadrant, left lower quadrant, and right lower quadrant It is important to note what organs are located in each abdominal region or quadrant to know where to auscultate, percuss, palpate, and to record the locations of findings during a physical examination. Figure 7. Subdivisions of the Abdominal Wall The abdominal wall is continuous but for descriptive purposes, it is subdivided into: → Anterior wall → Right and left lateral walls → Posterior wall The walls are musculoaponeurotic except for the posterior wall, which includes the lumbar region of the vertebral column The term anterolateral abdominal wall is used since the boundary between the anterior and lateral walls is indefinite Exercise: Describe the lesion. How will you tell your consultant? → The muscles located in the lateral aspect of the anterior wall intertwine except for the straight muscles like the rectus ANATOMY Abdomen in General PAGE 3 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. Some muscular and cutaneous nerve structures are located within = Transversus abdominis muscle both the anterior and lateral walls o Cannot be easily separated from the muscles The anterolateral abdominal wall extends from the thoracic cage o Extremely thin, being represented mostly by the to the pelvis epimysium superficial to or between muscles Table 3. Boundaries of the anterolateral abdominal wall → Muscles ▪ External & internal oblique muscles Superior Cartilages of the seventh to tenth ribs ▪ Transversus abdominis muscle Xiphoid process of the sternum → Endoabdominal or Transversalis Fascia ▪ Internal aspect of the abdominal wall lined with the Inferior Inguinal ligament membranous and areolar sheet of varying thickness Superior margins of the anterolateral aspects of the ▪ Although continuous, different parts of this fascia are named pelvic girdle (e.g., iliac crest, pubic crest, and pubic according to the muscle or aponeurosis it is lining symphysis) ▪ Transversalis Fascia: Portion lining the deep surface of transversus abdominis muscle and its aponeurosis A. LAYERS → Extraperitoneal fat ▪ Layer of fat before the peritoneum ▪ Found between the endoabdominal fascia and parietal peritoneum → Parietal Peritoneum ▪ Glistening lining of the abdominal cavity ▪ Formed by a single layer of epithelial cells and supporting connective tissue Remember in the different areas of the abdomen there would be different layers. The more complete layer of the abdominal wall is found in the RLQ below the arcuate line. B. MUSCLES Figure 8. Abdominal contents and layers of anterolateral abdominal Wall(Moore) From superficial to deep: → Skin Figure 9. Muscles of the Anterolateral abdominal wall(Moore) ▪ Attaches loosely to the subcutaneous tissue, except at the umbilicus, where it adheres firmly There are five (bilaterally paired) muscles in the anterolateral [See Appendix Table → Subcutaneous tissue abdominal wall: three flat muscles and two vertical muscles 13] ▪ Major site for storage of fat − Males: susceptible to subcutaneous accumulation of fat Three (3) flat muscles: in lower anterior abdominal wall → External oblique muscle ▪ Superior to the umbilicus, the subcutaneous tissue is ▪ Oriented inferomedially; “hands in your pocket” consistent with that found in most regions. ▪ Muscular laterally and aponeurotic towards the midline ▪ Inferior to the umbilicus, the deepest part of the − Aponeurotic fibers at the level of the ASIS thicken up to subcutaneous tissue is reinforced by many elastic and the pubic tubercle forming the inguinal ligament collagen fibers. o Continues as external spermatic fascia which covers ▪ Has 2 layers which are commonly found below the the spermatic cord umbilicus: → Internal oblique muscle − Superficial Fatty layer (Camper Fascia) ▪ Oriented superomedially; “hands on your chest” − Deep Membranous layer (Scarpa Fascia) ▪ Smaller and thinner than external oblique o Continues inferiorly into the perineal region as the ▪ Muscular laterally and aponeurotic towards the midline superficial perineal fascia (Colles fascia), but not into → Transversus abdominis muscle the thighs ▪ Oriented transversely to compress the abdominal contents − Investing (deep) fascia—superficial, intermediate and and increase the intra-abdominal pressure. deep ▪ Innermost of the three flat muscles o Covers external aspects of the three muscular layers: All three flat muscles are continued anteriorly and medially as = External oblique muscle strong sheet-like aponeuroses = Internal oblique muscle ANATOMY Abdomen in General PAGE 4 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. → Between the MCL and midline, the aponeuroses form the tough, aponeurotic, tendinous rectus sheath enclosing the rectus abdominis muscle → Aponeuroses interweave with the opposite side, forming a midline raphe, the linea alba, which extends from the xiphoid process to the pubic symphysis Two (2) vertical muscles: → Rectus abdominis muscle ▪ Long, broad, strap-like muscle ▪ Paired muscle separated at the midline by the linea alba ▪ Action: Powerful flexor of the thoracic and lumbar regions of the trunk ▪ Enclosed by tendinous anterior and posterior rectus sheath → Pyramidalis ▪ Small triangular muscle present only in 80% of the population ▪ Lies anterior to the most inferior part of the rectus abdominis ▪ Origin: Anterior surface of the pubis and the anterior pubic ligament ▪ Insertion: Linea alba ▪ Action: Tensor or pulls down linea alba Figure 11: Formation of rectus sheath and neurovascular structures Both vertical muscles are contained within the rectus sheath. of the anterolateral abdominal wall These muscles act as an antagonist of the diaphragm to produce expiration LINEA ALBA C. RECTUS SHEATH Interlacing fibers of the anterior and posterior layers of the rectus sheath at the anterior median line Strog, incomplete fibrous compartment of the rectus abdominis and pyramidalis muscles D. NEUROVASCULATURE Contents: NERVE SUPPLY → Superior and inferior epigastric arteries and veins Thoraco-abdominal nerves (T7-T11) [See Appendix Table 14] → Lymphatic vessels 7th-9th Lateral cutaneous branches (anterior rami of T7-T9) → Distal portions of the thoraco-abdominal nerves Subcostal nerve (anterior ramus of T12) Decussation and interweaving of the flat abdominal muscles’ Iliohypogastric nerve (L1) aponeuroses Ilio-inguinal nerve (L1) Flat abdominal muscles: external oblique m., internal oblique ms., and transversus abdominis ms. DERMATOMES Approx. ⅓ from the umbilicus to the pubic crest, aponeuroses of Map of dermatomes of the anterolateral abdominal wall is almost the flat abdominal muscles passes anterior to the rectus sheath = identical to the map of peripheral nerve anterior layer of the rectus sheath, leaving only the relatively thin → T7-T12: supplies most of the abdominal wall ; do not participate transversalis fascia to cover the rectus abdominis posteriorly at in plexus formation the level of the arcuate line → Exception at L1: anterior ramus bifurcates into two peripheral Arcuate Line nerves: (1) Iliohypogastric nerve and (2) Ilio-inguinal nerve, at the → Crescentic line demarcating the transition between the inguinal ligament aponeurotic posterior wall of the rectus sheath, covers the three quarters of the rectus Below the arcuate line: No posterior rectus sheath, only the transversus abdominis ms. Figure 12. Innervation of Anterolateral Wall ARTERIAL SUPPLY Distribution of deep abdominal blood vessels reflects the arrangement of the muscles [See Appendix Table 15] → Anterolateral abdominal wall vessels ▪ Oblique, circumferential pattern → Central anterior abdominal wall vessels ▪ More vertically oriented Figure 10. Muscles of the Anterolateral Abdominal Wall Primary blood vessels of the anterolateral abdominal wall: → Superior epigastric vessels and branches of the musculophrenic vessels ▪ Arise from the internal thoracic artery ANATOMY Abdomen in General PAGE 5 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. ▪ Supplies superior part of the rectus abdominis; E. INTERNAL SURFACE anastomoses with inferior epigastric artery → Inferior epigastric vessels ▪ Arise from the external iliac artery superior to the inguinal ligament ▪ Runs superiorly in the transversalis fascia to enter the rectus sheath below the arcuate line ▪ Enters lower rectus abdominis and anastomoses with the superior epigastric artery → Superficial circumflex iliac and superficial epigastric vessels → Posterior intercostal vessels Figure 14. Posterior aspect of the anterolateral abdominal wall of a male [Moore, p. 1010] Covered by transversalis fascia Has variable amount of extraperitoneal fat and parietal peritoneum Supra-umbilical part of the internal surface of the anterior abdominal wall has a sagittally oriented surface peritoneal reflection, the falciform ligament → Extends between the superior anterior abdominal wall and liver → Encloses round ligament of the liver and paraumbilical veins in its inferior free edge Round ligament of the liver (ligamentum teres hepatis): fibrous remnant of the umbilical vein, which passes from the umbilicus to the liver prenatally Figure 13: Arteries of the anterolateral abdominal wall Infraumbilical part of this surface has five umbilical folds: → 1 median umbilical fold VENOUS DRAINAGE → 2 medial umbilical folds Skin and subcutaneous tissue of the abdominal wall is with → 2 lateral umbilical folds intricate subcutaneous venous plexus → Drains superiorly: UMBILICAL FOLDS ▪ Internal thoracic vein (medially) ▪ Lateral thoracic vein (laterally) → Drains inferiorly: ▪ Superficial epigastric veins (femoral vein tributary) ▪ Inferior epigastric veins (external iliac vein tributary) Cutaneous veins surrounding the umbilicus anastomoses with paraumbilical veins → Paraumbilical veins: small tributaries of the hepatic portal vein; parallel the obliterated umbilical vein or the round ligament of the liver Thoraco-epigastric vein → Developed as a result of altered venous flow between ▪ Ex: Liver failure Importance: In clinics if a person is with prominent abdomino-thoracic vessels you must find possible problems in the liver such as portal hypertension LYMPHATIC DRAINAGE Figure 15. Umbilical Folds and Peritoneal Fossae [Google Images] Follows the pattern of the transumbilical plane Median umbilical fold (1) Superficial lymphatic vessels → Extends from the apex of the urinary bladder to the umbilicus → Accompany the subcutaneous veins → Covers median umbilical ligament (remnant of urachus) ▪ Superior to transumbilical plane ▪ Urachus: joins apex of the fetal bladder to umbilicus – Mainly drains to axillary lymph nodes Medial umbilical folds (2) – Few drains to parasternal lymph nodes → Lateral to the median umbilical fold ▪ Inferior to transumbilical plane Covers medial umbilical ligaments, formed by occluded parts of – Drains to superficial inguinal lymph nodes the umbilical arteries Deep lymphatic vessels Lateral umbilical folds (2) → Accompany the deep veins of the abdominal wall → Lateral to medial umbilical folds → Drains into: → Covers inferior epigastric vessels (bleeds when cut) ▪ External iliac lymph nodes ▪ Common iliac lymph nodes ▪ Right & left lumbar (caval & aortic) lymph nodes ANATOMY Abdomen in General PAGE 6 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. PERITONEAL FOSSAE Iliac crest → Palpated starting from the ASIS at the level of L4 vertebra Depressions lateral to umbilical folds Pubic crest, inguinal fold and iliac crests Table 4. Summary of the Peritoneal Fossae → Demarcates the inferior limit of the anterior abdominal wall Fossae Description Defect INGUINAL REGION Supravesical Extends between the ASIS and pubic tubercle hernia (external Between median Anatomically: structures exit and enter the abdominal cavity Supravesical and internal) and medial Clinically: potential sites of herniation fossa causes intestinal umbilical folds Inguinal ligament and iliopubic tract: bilaminar anterior (flexor) obstruction; retinaculum of the hip joint extremely rare Retinaculum: thickened fibrous band that occurs in relationship to - Between medial many joints with wide range of movement to retain the structure and lateral against the skeleton. It spans the subinguinal space through umbilical folds which passes the flexors of the hip and the neurovascular - Commonly structure that serves the lower limb. known as Direct inguinal Medial inguinal inguinal triangle hernias (less fossa of Hesselbach common) (inguinal triangles or Hesselbach triangles ) Lateral inguinal Lateral to the Indirect inguinal fossa lateral umbilical hernia (most folds, includes common type of deep inguinal rings hernia in lower abdominal wall) *Refer to Figure 15 F. SURFACE ANATOMY Figure 17. Formations of Inguinal region A. INGUINAL LIGAMENT Dense band constituting the most inferior part of the external oblique aponeurosis The medial ends of the inguinal ligament inserts into the pubic tubercle → Lacunar ligament of Gimbernat ▪ Some of the deeper fibers past posteriorly to attach to the superior pubic ramus lateral to the tubercle forming the arching lacunar ligament of Gimbernat Figure 16. Surface anatomy of anterolateral abdominal wall → Pectineal ligament of Cooper Umbilicus ▪ Most lateral of these fibers continue to run along the pecten → Reference for transumbilical plane pubis as the pectineal ligament of Cooper → Puckered indentation of skin in the center of anterior abdominal → Reflected inguinal ligament wall ▪ Some of the more superior fibers fan upward bypassing the → Typically seen at the level of IV disc between L3 & L4 pubic tubercle and crossing the Linea alba and blends with → Position varies with amount of subcutaneous fat present the lower fibers of the contralateral external oblique → Indicates the level of T10 dermatome aponeurosis forming the reflected inguinal ligament Epigastric fossa B. ILIOPUBIC TRACT → Slight depression in epigastric region, inferior to xiphoid Thickened inferior margin of transversalis fascia, that appears as a process fibrous band running parallel and posterior (deep) to the inguinal → Noticeable in supine position when the abdominal organs ligament spread out Seen in place of the inguinal ligament when the inguinal region is Linea alba viewed in its internal aspect during laparoscopy. → Its location is visible in lean individuals because of vertical skin The inguinal ligament and iliopubic tract, along with external and groove superficial to this raphe internal surface, span an area of innate weakness in the body wall Linea nigra in the inguinal region called the myopectineal orifice. → Heavily pigmented line in the middle skin external to the linea → Site of weakness in the inguinal region alba present in pregnant women (especially those with dark → Site of direct, indirect inguinal and femoral hernias occur hair and complexion) Inguinal fold C. INGUINAL CANAL → Shallow oblique groove overlying the inguinal ligament as it Formed in relation to the relocation of the testis during fetal extends between ASIS and pubic tubercle development Semilunar line In adult: approx. 4 cm long directed inferomedially throughout the → Slightly curved, linear impressions in the skin inferior part of the anterolateral abdominal wall → Extends from inferior costal margin near the 9th costal Structures transmitted: cartilages to pubic tubercles → Males: Spermatic cord → Clinically important because they are parallel with the lateral → Females: Round ligament of uterus edges of the rectus sheath (5-8 cm from midline) → Male & Female: The inguinal canal contains blood and Inguinal groove lymphatic vessels along with the ilioinguinal nerve → Indicates site of the inguinal ligament Has an opening at each end: Deep (internal) and Superficial → Skin crease that is parallel and superficial to the inguinal (external) inguinal ring ligament ANATOMY Abdomen in General PAGE 7 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. continuing VIDEO (see references for link to the video) onto cord as In the early stages of life as a fetus, certain parts of the external external genitalia were inside the abdomen. As they pushed their way out, spermatic they created a space called the inguinal canal. fascia Extends from the halfway point of the inguinal ligament Posterior Transversalis fascia Inguinal falx The two ends of the canal are called inguinal rings, Wall (conjoint superficial and deep. tendon) → Contents: plus the ▪ Male: Spermatic cord reflected ▪ Female: Round Ligament inguinal ▪ Both male & and female: Ilioinguinal nerve ligament Walls of the inguinal canal: Roof Transversalis Musculo-apo Medial crus Bottom: Inguinal ligament fascia neurotic of the Anterior: External oblique aponeurosis arches of external → Most anterior muscle of the abdominal wall internal oblique → The inguinal ligament is an extension or oblique and continuation of this aponeurosis transversus Lateral: Internal oblique muscle abdominis → Starts at the iliac crest, where it moves beside the muscles external oblique and is joined by transversus Floor Iliopubic tract Inguinal Lacunar abdominis, which begins further lateral on the iliac ligament ligament crest Dr. Paculan’s Mnemonics for the Boundaries of the Inguinal Canal: Table 5. Openings of Inguinal Canal MALT-SAIP (Superior-Anterior-Inferior-Posterior) Deep Inguinal Ring Superficial Inguinal RIng Muscles: Internal oblique & Tranversus abdominis Entrance to inguinal canal Exit by which the spermatic Aponeurosis of External & Internal oblique Location: cord or the round ligament Ligaments: Inguinal & Lacunar ligament → Superior to middle of emerges Transversalis fascia, Tendon: (Inguinal falx or Conjoint tendon) the inguinal ligament Slit-like opening in the → Medial location → Lateral to inferior aponeurosis of the external DEVELOPMENT OF INGUINAL CANAL IN MALES epigastric artery oblique, superolateral to Beginning of an the pubic tubercle evagination of the Parts of the aponeurosis transversalis fascia that that lie lateral and medial to forms an opening the superficial ring (and → Through an opening, form its margins) are crura: extraperitoneal ductus → Lateral crus: attaches deferens (vas deferens) to pubic tubercle and testicular vessels in → Medial crus: attaches males (or round to pubic crest ligament of uterus in → Intercrural crus: helps females) pass to enter prevent crura from the inguinal canal spreading apart (i.e. Transversalis fascia itself they keep the “split” in continues into the canal the aponeurosis from forming the innermost expanding) covering (internal fascia) of Sometimes open but it is the structures traversing fine since there is no actual the canal defect Must be closed: if open, hernia may occur Space of Bogros or Retroinguinal Space → Space between the transversalis fascia and parietal peritoneum → Where prosthetic mesh is overlaid in inguinal hernia repairs Inguinal canal is normally collapsed anteroposteriorly against the structures it conveys Between its two openings (rings), it has two walls (anterior and posterior), roof, and a floor Table 6. Boundaries of Inguinal Canal Lateral Medial Third/ Boundary Third/ Middle Third Superficial Deep Ring Ring Anterior Wall Lowermost Aponeurosis Aponeurosis fibers of of External of external internal oblique oblique oblique plus (lateral crus & (intercrural Figure 18. Development of Inguinal Canals in Males[Moore] lateral crus of intercrural fibers), with Testes develop in the extra peritoneal connective tissue in the aponeurosis fibers) fascia of superior lumbar region of the posterior abdominal wall (Refer to of external external Figure 19) oblique oblique ANATOMY Abdomen in General PAGE 8 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. Male Gubernaculum Processus vaginalis (of the peritoneum) → Fibrous tract connecting the primordial testis to the Transverses the transversalis fascia at the site of the deep anterolateral abdominal wall at the site of the future deep ring inguinal ring which forms the inguinal canal (similar to the of the inguinal canal development in males) and protrudes into the developing Processus vaginalis labium majus → A peritoneal diverticulum that traverses the developing inguinal → Obliterates by the end of 6th month of fetal development canal, carrying muscular and fascial layers of the anterolateral ▪ Except in males, the most inferior part becomes its serous abdominal wall before it as it enters the primordial scrotum sac engulfing the testis, the tunica vaginalis ▪ If it does not close (happens in 10% of male population), it Female Gubernaculum can cause indirect inguinal hernia (patent processus → A fibrous cord that connects the ovaries and the primordial vaginalis) uterus to the developing labium majus ▪ Closes a bit later than females because it becomes part of → It is represented postnatally by the: ovarian ligament the sac (between the ovary and the uterus) and the round ligament of ▪ Its stalk normally degenerates the uterus (between uterus and labium majus) Its distal saccular part forms the tunica vaginalis, the → Due to the attachment of the ovarian ligaments to the uterus, serous sheath of the testis and epididymis the ovaries do not relocate to the inguinal region Timeline: → However, the round ligament passes through the inguinal canal → 12th week: testis in the pelvis and attaches to the subcutaneous tissue of the labium majus → 28th week (7th month): testis is now close to the developing Timeline: inguinal ring and begins to pass through through the inguinal → 2 months: primordial ovaries are located on the dorsal canal (Refer to Figure _) abdominal wall ▪ It takes approximately 3 days to traverse it → 15th week: ovaries have descended through the abdominal → 32nd week (8th month): testis enters the scrotum wall, forming the inguinal canal on each side (similar to the Musculofascial extensions of the anterolateral abdominal wall (flat development in males) muscles of the abdominal wall, except the transverse abdominis) ▪ The round ligament passes through the canal and attaches ensheath the testis, its duct (ductus deferens) and its vessels and to the subcutaneous tissue of the labium majus nerves when they relocate. This accounts for the presence of their → 6th month: Processus vaginalis obliterates derivatives in the adult scrotum: ▪ With exception for its most inferior part, which becomes a → Internal spermatic fascia (from transversalis fascia) serous sac engulfing the ovaries (tunica vaginalis) → External spermatic fascia (from external oblique ▪ The round ligament persists and passes through the aponeurosis) inguinal canal → Cremaster muscle (from internal oblique muscle) → Labium majus/majora in females is homologous to scrotum in Newborns: the remnant of the gubernaculum has disappeared males → Inguinal canals of females are narrower, while infants of both DEVELOPMENT OF INGUINAL CANAL IN FEMALES sexes are shorter and more oblique ▪ Superficial inguinal rings of the canal lie almost directly anterior to the deep inguinal rings Will initial increased intraabdominal pressure cause herniation? No, it decreases in intra-abdominal pressure which will act on the inguinal canal forcing the posterior wall against the anterior wall and strengthening, this decreases the likelihood of herniation until the pressure overcomes the resistance on the floor D. SPERMATIC CORD, SCROTUM, AND TESTES Figure 20. Corresponding layers of the anterior abdominal wall, Figure 19. Development of Inguinal Canals in Females[Moore, 2018] scrotum, and spermatic cord External oblique fascia would go down into the pubic bone to The ovaries also develop in the superior lumbar region of the become the intercrural fibers and will become the external posterior abdominal wall and relocate to the lateral wall of the spermatic fascia pelvis ANATOMY Abdomen in General PAGE 9 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. → From the internal ridge, fibrous septa extend inward between [See Appendix Table 16] lobules of minute but long and highly coiled seminiferous Inguinal Hernias tubules in which the sperms are produced Seminiferous Tubule Figure 23. Direct (left) vs Indirect (right) Hernias Majority of abdominal hernias occur in the inguinal region accounting for 75% of abdominal hernias Figure 21. Testis with the tunica vaginalis opened Occur in both sexes, but most inguinal hernias (approximately 86%) occur in males because of the passage of the spermatic → Joined by straight tubules to the rete testis (a network of canals cord through the inguinal canal in the mediastinum of the testis) A protrusion of parietal peritoneum and viscera, such as the Epididymis small intestine, through a normal or abnormal opening from the cavity in which they belong Most hernias are reducible and can be returned to their normal place in the peritoneal cavity by appropriate manipulation Direct hernia passes through a weakened area of transversalis fascia in Hesselbach's triangle (lateral edge of rectus abdominis, the inferior edge of the inguinal ligament, and medial to inferior epigastric vessels) while an Indirect inguinal hernia arises lateral and superior to the course of the inferior epigastric vessels, lateral to Hesselbach's triangle, and then protrude through the deep or internal inguinal ring into the inguinal canal PERITONEUM AND PERITONEAL CAVITY A. PERITONEUM Continuous, glistening, slippery transparent serous membrane Lines the abdominopelvic cavity and invests the viscera Two layers → Parietal peritoneum → Visceral peritoneum Intraperitoneal organs are almost completely covered with visceral peritoneum. Figure 22. Structures of the testis and epididymis Extraperitoneal, retroperitoneal, and subperitoneal organs are → An elongated structure on the posterior surface of the testis outside the peritoneal cavity → Efferent ductules of the testis transport newly developed sperms to the epididymis from the rete testis B. PERITONEAL CAVITY ▪ Formed by minute convolutions of the duct of the Within the abdominal cavity epididymis, so tightly compacted that they appear solid Continues inferiorly into the pelvic cavity → Consists of the following: Potential space of capillary thinness between the parietal and ▪ Head of the epididymis visceral layers of peritoneum − Superior expanded part that is composed of lobules Contains peritoneal fluid formed by the coiled ends of 12–14 efferent ductules Peritoneal fluid ▪ Body of the epididymis → Composed of water, electrolytes, and other substances derived − Major part consisting of the tightly convoluted duct of the from intestinal fluid in adjacent tissues epididymis → Lubricates ▪ Tail of the epididymis → Contains leukocytes and antibodies that resist infection − Ductus deferens begins as the continuation of the Houses a great length of gut covered by peritoneum epididymal duct Extensive continuities between the parietal and visceral − Spermatocytes continue to mature and are stored peritoneum to convey necessary neurovascular structures throughout this duct The parietal and visceral peritoneum lining the peritoneal cavity − Transports the sperm from the epididymis to the within it have greater surface area than skin ejaculatory duct for expulsion via the urethra during ejaculation ANATOMY Abdomen in General PAGE 11 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. C. EMBRYOLOGY Gastroschisis: occurs when body wall closure fails in the PERITONEAL CAVITY abdominal region Early in its development, the embryonic body cavity MESENTERY (intraembryonic coelom) is lined by mesoderm (primordium of the peritoneum) Double layer of peritoneum At the later stage, the primordial abdominal cavity is lined by Invagination of the peritoneum by an organ and constitutes a parietal peritoneum, derived from the mesoderm, forming a continuity of visceral and parietal peritoneum closed sac Provides means for neurovascular communications between the → Peritoneal cavity- lumen of peritoneal sac organ and the body wall (posterior abdominal wall) Initially the primordial gut is suspended in the center of the peritoneal cavity by a posterior mesentery As the organs develop, it invaginates in varying degrees into the peritoneal sac acquiring visceral peritoneum. Figure 25. Mesentery OMENTUM Double-layered extension or fold of peritoneum → Greater omentum- prominent 4-layered peritoneal fold that hangs down like an apron → Lesser omentum- smaller, double-layered peritoneal fold Figure 24. Embryology EMBRYONIC TUBES AND BODY CAVITIES 3RD & 4TH WEEK Simultaneous development of gut tube and neural tube → Gut tube: ventrally (endoderm) → Neural tube: dorsally Mesoderm holds the tubes together Soon after it forms as a solid mesodermal layer, clefts appear in the lateral plate mesoderm that coalesces to split the layer into: → Visceral (Splanchnic) Layer ▪ Rolls ventrally and is intimately connected to gut tube ▪ Adjacent to the endoderm → Parietal (Somatic) Figure 26. Greater and Lesser Omentum ▪ Together with the overlying ectoderm, forms lateral body wall folds (one on each side of the embryo) D. PERITONEAL FORMATIONS Primitive body cavity → Space in between the parietal and visceral layers → Continuous cavity at this early stage Intermediate mesoderm forms the urogenital system Lateral plate mesoderm forms the body cavities 4TH WEEK Size begins to grow ventrally, forming two lateral body wall folds → These folds consist of the parietal layer of the lateral plate mesoderm, overlying ectoderm, and cells from adjacent somites that migrate into the mesoderm layer across the lateral somitic frontier As the fold progresses, endoderm folds ventrally and forms the gut tube By the end of the 4th week, the lateral body wall folds meet at the midline to fuse and close the ventral body wall, aided by the head and tail region, causing the embryo to curve in a fetal position Closure of the ventral body wall is complete except at the region of the connective stalk (future umbilicus) Omphalocele: ventral body wall defect that originates when portions of the gut tube (midgut) that normally herniates into the umbilical cord during the 6th to 10th weeks return to the abdominal cavity Figure 27. Principal formations of the peritoneum [Moore] ANATOMY Abdomen in General PAGE 12 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. PERITONEAL LIGAMENTS Some contain blood vessels and bleed if cut, such as the lateral Double-layered peritoneum that connects an organ to another umbilical folds, which contain the inferior epigastric arteries organ or to the abdominal wall [See Appendix Figure 36] PERITONEAL RECESS OR FOSSA A pouch of peritoneum that is formed by a peritoneal fold (e.g. the inferior recess of the omental bursa between the layers of the greater omentum, and the supravesical and umbilical fossae between the umbilical folds) E. SUBDIVISIONS OF PERITONEAL CAVITY Figure 28. Peritoneal ligaments [Moore, 2018] Table 9. Ligaments of the liver Ligament Description Coronary ligament (a.k.a. Connects the liver to the left/right triangular ligament) diaphragm Figure 29. Subdivisions of peritoneal cavity [Moore] Falciform ligament Connects the liver to the LESSER SAC OR OMENTAL BURSA anterior abdominal wall Space between two peritoneums Round ligament of the liver Fibrous remnant of the Extensive sac-like cavity that lies posterior to the stomach, lesser (a.k.a. Ligamentum teres umbilical vein omentum, and adjacent structures hepatis) Has two recesses: Hepatogastric ligament (a.k.a. Connects the liver to the → Superior recess membranous lesser omentum) stomach ▪ Limited superiorly by the diaphragm and the posterior layers Hepatoduodenal ligament Connects the liver to the of the coronary ligament of the liver (a.k.a. thick edge lesser duodenum → Inferior recess omentum) ▪ Located between the superior parts of the layers of the Table 10. Ligaments of the stomach greater omentum Ligament Description ▪ Most becomes sealed off from the main part posterior to the stomach after adhesion of the anterior and posterior layers Hepatogastric ligament (a.k.a. Connects the stomach to the of the greater omentum Gastrohepatic ligament) liver Enables smooth sliding or gliding of the stomach with the other Gastrophrenic ligament Connects the stomach to the structures posterior and inferior to it diaphragm Communicates with the greater sac through the omental Gastrosplenic ligament (a.k.a. Connects the stomach to the foramen, a.k.a. epiploic foramen or the foramen of Winslow Gastrolienal ligament) spleen → An opening situated posterior to the free edge of the lesser Gastrocolic ligament Connects the stomach to the omentum (hepatoduodenal ligament) colon → Can be located by running a finger along the gallbladder Table 11. Ligaments of the spleen to the free edge of the lesser omentum Ligament Description → Usually admits two fingers Gastrosplenic ligament (a.k.a. Connects the spleen to the Table 12. Boundaries of the Omental Foramen Gastrolienal ligament) stomach Anterior Hepatoduodenal ligament (free edge of lesser Splenorenal ligament Connects the spleen to the omentum), containing the hepatic portal vein, kidneys hepatic artery, and bile duct Posterior IVC and a muscular band, the right crus of the BARE AREAS diaphragm, covered anteriorly with parietal Although intraperitoneal organs may be almost entirely covered peritoneum with visceral peritoneum, every organ must have an area that is Superior Liver, covered with visceral peritoneum not covered to allow the entrance or exit of neurovascular Inferior Superior or first part of the duodenum structures; such areas are called bare areas Formed in relation to the attachments of the peritoneal formations GREATER SAC to the organs, including mesenteries, omenta, and ligaments that Main and larger part of the peritoneal cavity convey the neurovascular structures A surgical incision through the anterolateral abdominal wall enters the greater sac Transverse mesocolon divides the abdominal cavity into two PERITONEAL FOLDS compartments: A reflection of peritoneum that is raised from the body wall by → Supracolic compartments underlying blood vessels, ducts, and ligaments formed by ▪ Contains the stomach, liver, and spleen obliterated fetal vessels (e.g., the umbilical folds on the internal surface of the anterolateral abdominal wall) ANATOMY Abdomen in General PAGE 13 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. → Infracolic compartments Attached to the latissimus dorsi ▪ Contains the small intestine, ascending, and descending colon ▪ Lies posterior to the greater omentum ▪ Divided into right and left infracolic spaces by the mesentery of the small intestine → Paracolic gutters ▪ Permits free communication between the supracolic and infracolic compartments ▪ Grooves between the lateral aspect of the ascending or descending colon and the posterior abdominal wall Significance of knowing the contents of the bursa If not accessed during an injury, might miss bleeding Potential space of accumulation of fluid (e.g. blood, abscess, abdominal fluid, gastric content) POSTERIOR ABDOMINAL WALL Figure 31. Fascia and aponeurosis of abdominal wall [Moore] Mainly composed of the following structures: QUADRATUS LUMBORUM FASCIA → 5 lumbar vertebrae and associated IV discs (centrally) → Posterior abdominal wall muscles including the psoas, Anterior layer of the thoracolumbar fascia quadratus lumborum, iliacus, transversus abdominis, Covers the anterior surface of the quadratus lumborum ms and oblique muscles (laterally) Thinner, more transparent layer than the other two layers → Diaphragm (superior part of the posterior wall) → Attaches to anterior surfaces of the transverse processes of → Fascia, including thoracolumbar fascia the lumbar vertebrae, iliac crest, & 12th rib → Lumbar plexus (anterior rami of lumbar spinal nerves) Anterior layer of the thoracolumbar fascia → Fat, nerves, vessels, and lymph nodes B. MUSCLES A. FASCIA Covered with a continuous layer of endoabdominal fascia that lies between the parietal peritoneum and the muscles Continuous with the transversalis fascia that lines the transversus abdominis muscle [Moore, 2018] [See Appendix Table 17] Figure 32. Muscles of the Posterior Abdominal Wall PSOAS MAJOR Long, thick, fusiform muscle that lies lateral to the lumbar vertebrae Passes inferolaterally, deep to the inguinal ligament to reach the lesser trochanter of the femur Lumbar plexus of the nerves is embedded in the posterior part of psoas major, anterior to the lumbar transverse process ILIACUS Large, triangular muscle that lies along the lateral side of the inferior part of the psoas major Most of its fibers join the tendon of the psoas major → Together with psoas muscle, It forms the iliopsoas ▪ Chief flexor of the hip Figure 30. Fascia of the Posterior Abdominal Wall[Moore, 2018] ▪ Stabilizes the hip joint and helps maintain the erect posture at the joint PSOAS FASCIA ▪ The psoas and iliacus share in hip flexion; however, only the Covers the psoas major and is attached medially to the lumbar psoas can produce movement (flexion or lateral bending) of vertebrae and pelvic brim the lumbar vertebral column Thickened superiorly to form the medial arcuate ligament Fuses laterally with quadratus lumborum and thoracolumbar QUADRATUS LUMBORUM fascias Quadrilateral muscle forms a thick muscular sheet in the posterior Inferior to the iliac crest, it is continuous with the part of the iliac abdominal wall that lies adjacent to the lumbar transverse fascia covering the iliacus processes and is broader inferiorly Close to the 12th rib, the lateral arcuate ligament crosses the THORACOLUMBAR FASCIA quadratus lumborum Extensive fascial complex attached to the vertebral column → Subcostal nerve passes posterior to this ligament and runs medially that, in the lumbar region, has posterior, middle, and inferolaterally on the quadratus lumborum anterior layers with muscles enclosed between them. Branches of the lumbar plexus run inferiorly on the anterior It is thin and transparent in the thoracic parts of the deep muscles, surface of the muscle but it is thick and strong in the lumbar region ANATOMY Abdomen in General PAGE 14 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. *Note: Refer to the appendix for the OINA of the Muscles of the ▪ Veins that correspond to the unpaired visceral branches of Posterior Abdominal Wall. the aorta are instead tributaries of the hepatic portal vein → Braches: C. NEUROVASCULATURE ▪ Paired visceral ARTERIAL SUPPLY − Right suprarenal vein (left suprarenal vein drains to left renal vein) − Right and left renal veins − Right gonadal (testicular or ovarian) vein (left gonadal vein drains to left renal vein) − Left suprarenal and gonadal veins drain indirectly into the IVC because they are tributaries of the left renal vein ▪ Paired parietal − Inferior phrenic veins − 3rd and 4th lumbar veins − Common iliac veins Figure 33. Branches of the abdominal aorta [Moore] Abdominal Aorta → ~13 cm in length → Begins at the aortic hiatus in the diaphragm at the level of T12 vertebra and ends at the level of the L4 vertebra by dividing into the right and left common iliac arteries → Branches [See Appendix Table 18] ▪ Anterior midline (unpaired visceral) - Celiac (T12) - Superior mesenteric (L1) - Inferior mesenteric (L2) ▪ Lateral (paired visceral) - Suprarenal (L1) - Renal (L1) - Gonadal (L2) Figure 34. Inferior Vena Cava [Moore] ▪ Posterolateral (paired visceral) NERVES - Subcostal (L2) - Inferior phrenic (T12) - Lumbar (L1-L4) *Note: Refer to the appendix for the Branches of the Abdominal Aorta VENOUS DRAINAGE Veins of the posterior abdominal wall are tributaries of the IVC, except: → Left testicular or ovarian vein ▪ Enters the left renal vein instead of the IVC Inferior Vena Cava → Largest vein in the body and has no valves except for a variable, non-functional valve at its orifice in the right atrium of the heart → Returns poorly oxygenated blood from the lower limbs, most of the back, the abdominal walls, and the abdominopelvic viscera → Blood from the abdominal viscera passes through the portal venous system and the liver before entering the IVC via the hepatic veins Figure 35. Nerves of the Posterior Abdominal Wall [Moore, 2018] → Begins anterior to the L5 vertebra by the union of the common Subcostal nerves iliac veins → Anterior rami of T12 ▪ Occurs ~2.5 cm to the right of the median plane, inferior to → Arise in the thorax, pass posterior to the lateral arcuate the aortic bifurcation and posterior to the proximal part of the ligaments into the abdomen, and run inferolaterally on the right common iliac artery anterior surface of the quadratus lumborum → Ascends on the right side of the bodies of the L3-L5 vertebrae → Passes through the transversus abdominis and internal oblique and on the right psoas major to the right of the aorta ms to supply the external oblique and skin of the → Leaves abdomen by passing through the caval opening in the anterolateral abdominal wall diaphragm and enters the thorax at the T8 vertebral level Lumbar spinal nerves → Tributaries of the IVC correspond to the paired visceral and → L1-L5 parietal branches of the abdominal aorta ANATOMY Abdomen in General PAGE 15 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. → Pass from the spinal cord through the IV foramina inferior to 9. The transpyloric plane will traverse which among the the corresponding vertebrae, where they divide into posterior following structures. and anterior rami a. Xiphoid process ▪ Each ramus contains sensory and motor fibers b. Appendix ▪ Posterior rami c. Neck of the pancreas − Pass posteriorly to supply the muscles of the back and d. Thoracic esophagus overlying skin 10. A supravesical hernia will be visible between which of the ▪ Anterior rami following structures of the umbilical folds? − Pass laterally and inferiorly to supply the skin and a. Median and lateral muscles of the inferiormost trunk and lower limb b. Medial and lateral Abdominal part of the sympathetic trunks c. Lateral to the lateral fold → Consist of four lumbar paravertebral sympathetic d. Median and medial ganglia and interganglionic branches ANS: → Continuous with the thoracic part of the trunks deep to 1. C. The superior part of the ascending colon can be found in the right upper the medial arcuate ligaments of the diaphragm quadrant while the inferior part of the descending colon can be found in the → Lumbar trunks descend on the anterolateral aspects of the left lower quadrant of the abdomen. bodies of the lumbar vertebrae in a groove formed 2. B. Both the Camper and Scarpa fasciae are subcutaneous layers found by the adjacent psoas major immediately under the skin meanwhile the transversalis fascia is deeper 3. C. The Cremasteric fascia is derived from the Investing fascia of both the → Inferiorly crosses the sacral promontory and continue superficial and deep surfaces of the internal oblique muscle meanwhile the inferiorly into the pelvis as part of the trunks internal spermatic fascia is derived from the transversalis fascia Lumbar plexus of nerves 4. B. The greater omentum connects the stomach to the transverse colon. → Femoral nerve (L2-L4) 5. A..The left testicular and ovarian vein are not tributaries of the IVC and → Obturator nerve (L2-L4) instead enters the left renal vein → Lumbosacral trunk (L4, L5) 6. A. The falciform ligament connects the anterior part of the liver to the ventral → Ilio-inguinal and iliohypogastric nerve (L1) wall of the abdomen, the hepatogastric ligament or connects the liver to the lesser curvature of the stomach, and the round ligament of the liver → Genitofemoral nerve (L1, L2) connects the liver to the umbilicus. → Lateral cutaneous nerve of the thigh (L2, L3) 7. A. Vertical raphe at abdominal region between the rectus abdominis → Accessory obturator nerve (L3, L4) III. REVIEW QUESTIONS 1. Which of the following is found in the upper left quadrant of the abdomen? a. Superior part of the descending colon b. Inferior part of the descending colon c. Superior part of the ascending colon 2. Which layer of the abdominal wall lines the deep surface of transversus abdominis muscle a. Scarpa fascia b. Transversalis fascia c. Camper fascia 3. Which of the following is spermatic fascia is derived from the external oblique aponeurosis of the anterolateral abdominal wall 8. C. The femoral artery gives rise to the superficial circumflex iliac artery while a. Cremasteric fascia the internal iliac artery gives rise to a variable number of branches including b. Internal spermatic fascia but not limited to the superior gluteal and iliolumbar arteries c. External spermatic fascia 9. C. The xiphoid process serves as the upper marker of the transpyloric plane 4. Which of the following connects lesser curvature of the since this plane is supposed to be halfway between the xiphoid process and stomach and the duodenum to the liver? umbilicus; the appendix is too far down and is located in the right iliac a. Greater omentum region, while the thoracic esophagus is too far up and is located in the b. Lesser omentum superior mediastinum. 10. D. 5. The left ovarian vein is a tributary of the inferior vena cava a. False b. True V. REFERENCES 6. Which among the structures attaches the liver to the Moore, K.L., Dalley, A.F., Agur, A.M.R. (2018). Clinically Oriented diaphragm? Anatomy (8th ed.). Wolters Kluwer a. Coronary ligament Read, J. W., Ibrahim, N., Jacombs, A. S., Elstner, K. E., Saunders, b. Falciform ligament J., & Rodriguez-Acevedo, O. (2022). Imaging Insights Into c. Hepatogastric ligament Abdominal Wall Function. Frontiers in Surgery, 9, 799277. d. Round ligament of the liver Sadler, T. W. (2019). Langman’s medical embryology (14th Ed.). 7. The ___ lies vertically between two (2) rectus abdominis Wolters Kluwer muscles. Dr. Paculan. (2022). Abdomen in General Video Lecture a. Linea alba 2025 Trans b. Linea semilunaris Asynchronous recording c. Inguinal ligament d. McBurney’s Incision 8. The deep circumflex iliac artery originates from which structure a. Femoral artery YouTube video for inguinal canal b. Aorta c. External iliac artery d. Internal iliac artery ANATOMY Abdomen in General PAGE 16 of 18 ANATOMY | LE 1 Abdomen in General | Ma. Jenina Angela Esguerra-Paculan, M.D. VII. APPENDIX Ta