Abdominal wall 腹壁

1. Abdominal wall腹壁 山东大学医学院解剖教研室 李振华

2. Boundaries of the abdomen Boundaries • Superiorly－ xiphoid process, lower border of costal arch, 11th and 12th ribs, vertebra T12 • Inferiorly－superior border of pubic symphysis, pubic crest, pubic tubercle, fold of inguinal canal, anterior superior iliac spine, iliac crest, spinous process of L5

3. The abdominal regions 腹部分区——Nine regions Epigastric region 腹上区 R. hypochondriac region 右季肋区 L. hypochondriac region 左季肋区 R. lateral regions 右外区 L. lateral regions 左外侧区 R. inguinal region右腹股沟区 Umbilical region 脐区 L. inguinal region 左腹股沟区 Pubic region 耻区

4. Left and right upper quadrants Left and right lower quadrants The abdominal regions 腹部分区——Four quadrants

5. Landmarks of abdomen • Pubic symphysis • Pubic tubercle • Iliac crest • Umbiicus • Linea semilunaris • Transpyloric plane

8. Anterolateral abdominal wall Layers( from superficial to deep) • Skin • Superficial fascia • Anterolateral muscles • Transverse fascia 腹横筋膜 • Extraperitoneal fascia 腹膜下筋膜 • Parietal peritoneum 壁腹膜

9. Anterolateral abdominal wall Superficial fascia －divisions below umbilicus • Fatty layer (Camper’s fascia) continuous with the superficial fascia over the rest of the body. • Membranous layer (Scarpa’s fascia) passes over the inguinal ligament to fuse the deep fascia of the thigh (fascia lata) approximately one fingerbreadth below the inguinal ligament. In the midline, it is not attached to the pubis but instead from a tubular sheath for the penis (clitoris). In the perineum, it is attaches on each side to the margins of the pubic arch and is know as Colles’ fascia.

10. Superficial vessels and cutaneous nerves • Arteries • Superficial epigastric a. • Superficial iliac circumflex a. • Veins • Thoracoepigastric v. • Superficial epigastric v. • Cutaneous nerves • Anterior and lateral cutaneous n. of lower six thoracic • Iliohypogastric n. (first lumb nerves)

11. Superficial vessels and cutaneous nerves • Lymph drainge • Superficial lymph vessels above the level of the umbilicus grain upward into the pectoral Ln. • The vessels below this level drain downward into the superficial inguinal Ln.

12. Muscles of abdomen

13. Muscles of abdomen Anterolateral group • Obliquus externus abdominis 腹外斜肌 • Obliquus internus abdominis 腹内斜肌 • Transversus abdominis 腹横肌 • Rectus abdominis 腹直肌

14. Muscles of abdomen Posterior group • Quadratus lumborum 腰方肌 • Psoas major 腰大肌

15. Obliquus externus absominis 腹外斜肌 • General direction of fibers: downward, forward and medially (run down and inward)

16. Obliquus externus absominis 腹外斜肌 Structures • Inguinal ligament腹股沟韧带 • Lacunar ligament腔隙韧带 • Superficial inguinal ring腹股沟管浅环－triangular-shaped defect in aponeurosis of obliquus externus abdominis above pubic tubercle

17. Superficial inguinal ring

18. Obliquus internus abdominis 腹内斜肌 • Deep to obliquus externus abdominis • General direction of fibres: upwards, forwards and medially

19. Transversus abdominis 腹横肌 • Deep to obliquus internus • General direction of fibers: run horizontally forward.

20. Transversus abdominis腹横肌 • Inguinal falx腹股沟镰 • Obliquus internus abdominis has a lower, free border that arches over spermatic cord • Inserted with transversus abdominis fiber into medial part of pecten of pubis • Cremaster提睾肌 • Dirived from the lower fibers of the obliquus internus abdominis and transversus abdominis • Around the spermatic cord and testis

21. Rectus abdominis 腹直肌 • Position: lie on to either of midline • Origin: pubic crest and symphysis • Insertion: xiphoid and 5th-7th costal cartilages • Tendinous intersections腱划3-4 • linea semiluaris半月线

22. Similar functions for above four pairs of muscles • Support and compress the abdominal viscera • Increase intra-abdominal pressure, aid in expulsive efforts-vomiting, coughing, sneezing, defecation, urination and childbirth. • Depress ribs, assist in (the act of force(4)expiration. • Flex, lateral flex, and rotate vertebral column

23. Sheath of rectus abdominis 腹直肌鞘 Anterior layer • Formed by fusion of aponeurosis of obliquus externus abdominis and anterior leaf of aponeurosis of obliquus internus abdominis

24. Sheath of rectus abdominis 腹直肌鞘 Posterior layer • Formed by fusion of posterion leaf of aponeurosis of obliquus internus abdominis and aponeurosis of transversus abdominis • Absent in about 4-5cm below the umbilicus, where aponeuroses of all three muscles form anterior layer the lower free border named arcuate line 弓状线 • Below this line rectus abdominis in contact with transverse fascia

25. Muscles of abdomen Linea alba白线 －tendinous raphe between right and left recti from xiphoid to pubic symphysis

26. Deep vessels of abdomen Arteries • Superior and inferior epigastric arteris • Lower posterior intercostal aa. • Subcostal a. • Deep iliac circumflex a. • Four lumbar a.

27. Deep nerves of abdomen • Lower five intercostals nerves • Subcostal nerve • Run between obliquus internus and tranversus abdominis.

28. Deep nerves of abdomen Iliohypogastric n.髂腹下神经 • Arises from lumbar plexus • Passes forward in the interval between obliquus internus and tranversus abdominis • Pieces obliquus internus abdominis 2.5 cm medial to anterior superior iliac spine • Pieces aponeurosis of obliquus externus abdominisabout 2.5 cm above superficial inguinal ring

29. Deep nerves of abdomen Ilioinguinal n.髂腹股沟神经 • Arises from lumbar plexus • Runs parallel with iliohypogastric n. at a lower level • Enters inguinal canal and exits through superficial inguinal ring • Supplies the transversus abdominis, obliquus internus, and obliquuse externus abdiminis. It also supplies the skin just above the symphysis pubis and the scrotum or greater lip of pudendum.

30. Deep nerves of abdomen Genitofemoral n.生殖股神经 • Arises from lumbar plexus • Emerges through superficial inguinal ring and supplies the cremaster muscle

31. Inguinal region 腹股沟区 Boundaries • Inguinal ligament • Lateral margin of rectus abdominis • A horizontal line stretching from anterior iliac spine to lateral margin of rectus abdominis

32. Inguinal canal 腹股沟管 Position: oblique passage, 4cm long, located 1.5cm above medial half of inguinal ligament

33. Boundaries of inguinal canal • Anterior wall • Aponeurosis of obliquus externus abdominis • Obliquus internus abdominis (lateral third of wall) • Posterior wall • Transverse fascia • Inguinal flax medially • Roof－arching fibers of obliquus internus and transversus abdominis • Floor－inguinal ligament

34. Boundaries of inguinal canal Two openings • Superficial inguinal ring腹股沟管浅环 －a triangular-shaped defect in the aponeurosis of the obliquus externus abdominis and lies immediately above and medial to the pubic tubercle

35. Boundaries of inguinal canal Two openings • Deep inguinal ring腹股沟管深环 －an oval opening in transverse fascia and lies approximately 1.5cm above midpoint of inguinal ligament

36. Mechanics of the inguinal canal • The inguinal canal is a site of potential weakness in both sexes. • On coughing and straining (as in micturition, defecation, and parturition), the arching lowers fibers of the obliquus internus and transversus abdominis contract and flatten the arch. • In turn, this lowers the roof of the canal toward the floor and virtually closes the canal.

37. Structures passing through the inguinal canal • In males • Spermatic cord 精索 • Ilioinguinal nerve 髂腹股沟神经 • In females • Round ligament of uterus 子宫圆韧带 • Ilioinguinal nerve 髂腹股沟神经

38. Descent of testes Seven-week embryo showing the testis before its descent from the dorsal abdominal wall

39. Descent of testes Fetus at 28 week the testis passing through the inguinal canal

40. Descent of testes Newborn

41. Inguinal Triangle (of Hesselbach) 腹股沟三角 Boundaries • Medially: Lateral border of rectus abdominis • Laterally: Inferior epigastric artery • Inferiorly: Inguinal ligament

42. Indirect inguinal hernia and direct inguinal hernia Direct inguinal hernia Indirect inguinal hernia

43. Anterior abdominal wall • Transverse fascia 腹横筋膜 • Extraperitoneal fascia 腹膜外筋膜 • Parietal peritoneum 壁腹膜

44. Landmarks and surface anatomy • Xiphoid process • Costal arch • Anterior superior iliac spine • Iliac crest • Superior border of pubic symphysis • Pubic tubercle

45. Landmarks and surface anatomy • Linea alba • Rectus abdominis • Tendinous intersections • Linea semilunaris • Umbilicus: at the level of L3 ~ L4 • Inguinal ligament

46. Median or midline incision Subcostal incision Muscle-splitting incision Left paramedian incision Transverse incision Suprapubic incision Layer ?

47. Obliquus externus abdominis Inguinal ligament Superficial inguinal ring Obliquus internus abdominis Transversus abdominis Inguinal falx Rectus abdominis Tendinous intersections Sheath of rectus abdominis arcuate line inferior epigastric artery Posterior intercostal a. Intercostals nerve Iliohypogastric n. Ilioinguinal n. Spermatic cord ★You must identify follow structures！