ANATOMY OF ANTERIOR ABDOMINAL WALL

ANATOMY OF ANTERIOR ABDOMINAL WALL, useful for undergraduates

1. ANATOMY OF ANTERIOR ABDOMINAL WALL Presented By, Dr. Prajwal R K , Dept. of General surgery KIMS, Bengaluru

2. INTRODUCTION 2 The anterior abdominal wall constitutes a hexagonal area Superiorly – by the costal margins and xiphoid process, Laterally – by the midaxillary line, and Inferiorly – by the iliac crests, pubis and pubic symphysis. This includes Inguinal Region also…

3. SURFACE TOPOGRAPHY 3 four-quadrant pattern nine-region organizational description

4. INTRODUCTION 4 Layers of the abdominal wall Skin Soft Tissue Muscle and connective tissue

5. SOFT TISSUE 5 Superficial fascia Between dermis and the muscles superficial fatty layer (Camper’s fascia) deep membranous layer (Scarpa’s fascia). Deep adipose layer

6. SUPERFICIAL LAYER (Camper’s fascia) 6 It’s continuous with superficial fat over the rest of the body. In the scrotum is modified as a thin smooth muscular layer called dartos muscle

7. DEEP MEMBRANOUS LAYER (Scarpa’s fascia) 7 Measured histologically, it is between 0.5 and 1 mm thick. Superiorly, it is continuous with the superficial fascia over the remainder of the trunk In the midline, it is adherent to the linea alba and pubic symphysis

8. DEEP MEMBRANOUS LAYER (Scarpa’s fascia) 8 Inferiorly, it fuses with the iliac crest fuses with the fascia lata at the inguinal flexure it extends on to the scrotum, it becomes continuous with the membranous layer of superficial fascia of the perineum ( Colles ’ fascia)

9. DEEP MEMBRANOUS LAYER (Scarpa’s fascia) 9 In the male, it extends on to the dorsum of the penis to form the fundiform ligament of penis

10. Schematic representation of the layers of the anterolateral abdominal wall. 10 1, skin; 2, fatty layer of superficial fascia (Camper fascia); 3, neurovascular supply of superficial fascia; 4, membranous layer of superficial fascia (Scarpa fascia); 5, space with areolar tissue; 6, deep fascia (outer investing fascia of external oblique muscle); 7, external oblique muscle; 8, inner investing fascia of external oblique muscle and outer investing fascia of internal oblique muscle (they fuse; here presented separately for didactic reasons); 9, internal oblique muscle; 10, inner investing fascia of internal oblique muscle and outer investing fascia of tranasversus abdominis muscle (they fuse; here presented separately); 11, neurovascular bundle of abdominal muscles (between internal oblique and transversus abdominis muscles); 12, transversus abdominis muscle; 13, transversalis fascia (the inner investing fascia of the transversus muscle); 14, parietal compartment of preperitoneal space; 15, membranous layer of preperitoneal tissue; 16, preperitoneal fat in the visceral compartment of preperitoneal tissue; 17, peritonmeum .

11. MUSCLES of ANTERIOR ABDOMINAL WALL 11 5 Muscles 3 flat muscles External Oblique Internal Oblique Transersus abdominis 2 vertical muscles Rectus abdominis Pyramidalis

12. EXTERNAL OBLIQUE 12

13. INTERNAL OBLIQUE 13

14. TRANSVERSUS ABDOMINIS 14

15. RECTUS ABDOMINIS 15

16. PYRAMIDALIS 16

17. TRANSVERSALIS FASCIA 17 thin layer of connective tissue lying between the deep surface of transversus abdominis and the extraperitoneal fat Posteriorly, it fuses with the thoracolumbar fascia transversalis fascia is prolonged as the internal spermatic fascia

18. PERITONEUM 18 The peritoneum lining the walls is the parietal peritoneum ; The peritoneum covering the viscera is the visceral peritoneum

19. Rectus Sheath 19 Rectus abdominis on each side is enclosed by a fibrous sheath formed from the aponeuroses of all three lateral abdominal muscles anterior portion fuses with periosteum and ligaments at sites of the muscle’s attachments

20. Rectus Sheath 20 Each aponeurosis is bilaminar anterior leaves run obliquely upwards Posterior leaves run obliquely downwards

21. Rectus Muscle and Sheath 21

22. Linea Alba ( the white line) 22 The linea alba is a tendinous raphe extending from the xiphoid process to the pubic symphysis and pubic crest lies between the two recti 15–22 mm along its course, widest at or just above the umbilicus and narrowing at superior and inferior extremes

23. Linea Alba ( the white line) 23 completely avascular – preferred location for incision and intra-abdominal access lack of muscular coverage leads to weakness and the formation of the majority of de novo ventral hernias Ultimately, the goal of abdominal wall reconstruction remains to restore linea alba by bringing the paired rectus muscles back to the midline

24. ARCUATE LINE OF DOUGLAS 24 linea semicircularis Located one-third of the distance between the umbilicus and the pubis the arcuate line represents the lower limit of the posterior rectus sheath Below the arcuate line only the transversalis fascia remains between the rectus abdominis and peritoneum

25. ARCUATE LINE OF DOUGLAS 25 Here, both Spigelian and arcuate line hernias may occur arcuate line also serves as a landmark where the inferior epigastric vessels perforate the rectus abdominis The arcuate line must be incised at its lateral-most point in order to enter the space of Retzius and Bogros from within the rectus sheath

26. Umbilical Region 26

27. Umbilical Region 27 It consists of skin, a fibrous layer (representing the area of fusion between the round ligament of the liver, the median umbilical ligament, and two medial umbilical ligaments), the transversalis fascia, the umbilical fascia surrounding the urachal remnant, and peritoneum

28. Umbilical Region 28 Variations in umbilical ring (UR) and umbilical fascia seen from posterior (peritoneal) surface of body wall

29. SEMILUNAR LINE (LINEA SPIGELI) 29 Extends from the tip of the ninth costal cartilage to the pubic tubercle. site of transition from the aponeurotic part to the muscular part of the transverse abdominal muscle

30. SEMILUNAR LINE (LINEA SPIGELI) 30

31. SEMILUNAR LINE (LINEA SPIGELI) 31 The spigelian aponeurosis is the aponeurosis of the transverse abdominal muscle limited by the linea semilunaris laterally lateral edge of the rectus muscle medially. weakest point is at the intersection between the semilunar and semicircular line

32. Comparison of upper and lower three-fourths of anterior abdominal wall 32 Upper Midline Lower Midline Linea alba well developed Linea alba poorly developed Right and left recti well separated Right and left recti close together Anterior and posterior layers of sheath present Only anterior layer of sheath present Aponeurosis of external oblique weak or absent Aponeurosis of external oblique strong and well developed

33. Vessels of anterior abdominal wall 33 EOP - Ext Oblique Perforators SCI - Superficial Circumflex Iliac SE - Superior Epigastric DCI - Deep Circumflex Iliac IE - Deep , inferior Epigastric Artery SIEA - Superficial inferior Epigastric artery

34. Blood Supply 34

35. Blood Supply 35

36. Vascular supply to the abdominal wall with delineated Huger Zones I–III 36 Zone I – SEAs and DIEAs – rectus abdominis and overlying subcutaneous tissue and skin Zone II – SIEA and superficial external pudendal arteries – superficial fascia and skin The DIEAs and deep circumflex iliac arteries supply the musculature in this lower area. Zone III – lumbar and intercostal arteries

37. Vascular territories 37

38. Lymphatics 38 Superficial lymphatics above the umbilicus pass in a superior direction to the axillary nodes , below the umbilicus passes in an inferior direction to the superficial inguinal nodes.

39. Nerve Supply 39 The skin and muscles of the anterolateral abdominal wall are supplied by T7 to T12 and L1 spinal nerves

40. Nerve Supply 40 The lateral neurovascular structures travel in the TAP between the TAM and IOM Delivery of local anesthetic into this plane provides blockade to the sensory nerves TAP block – Improvements in post-operative pain scores, opioid use, and hospital stay

41. EXTRAPERITONEAL SPACES 41 Space of Retzius Space of Bogros

42. Landmarks 42 Inguinal Landmarks in Hernia Repair: Warning Triangles and Corona Mortis

43. Incisions on Abdominal Wall 43 “ Pray before surgery, but remember: God will not alter a faulty incision” • Keeney’s Dictum Maingot’s 3 requirements • Accesibility • Extensibility • Security

44. Varieties of Abdominal incisions 44

45. Midline Incisions 45

46. Paramedian Incision 46

47. Pararectus Incision (Kammerer-Battle) 47

48. Midrectus ( transrectus )Incisions 48

49. Pfannelstiel Incision 49

50. Ventral hernias 50 Umbilical–paraumbilical Epigastric Incisional Parastomal Spigelian Lumbar Traumatic

51. Lumbar hernias 51

52. REFERENCES 52