lecture 2.pptx on abdomen internal external

Anatomy of abdomen and parts

1. ANATOMY OF ANTERIOR ABDOMEN AND PERITONEUM

2. Organization of the antero -lateral abdominal wall BOUNDARIES Superiorly: Xiphoid process.( Xiphisternum ) Costal cartilages of the 7th and 10th ribs. Inferiorly: Iliac crest. Anterior superior iliac spine. Inguinal ligament. Pubic tubercle, pubic crest and pubic symphysis . Divided into 4 quadrants i.e Right and left upper quadrants Right and left lower quadrants  

3. Transpyloric plane(L1, L2) Transtubercular plane Mid-clavicular/ mid-inguinal line

4. Abdominal Regions

5. Divisions of the abdomen Can be Divided into 9 regions. Two vertical planes- midclavicular Two horizontal planes: Subcostal plane – joining the most inferior points of the costal margins, and passing at L3. Transtubercular plane- joining the tubercles of the iliac crest.   Note the 9 regions. Right and left hypochondrial regions (1and 3) Middle epigastric region (2) Right and left lumbar regions (6 and 4) A middle umbilical region (5) Right and left iliac (inguinal) region (7and 9) A middle hypogastric / suprapubic region (8)

6. Abdominal wall Anterolateral abdominal wall Posterior abdominal wall

7. Layers of the abdominal wall through L1 skin superficial fascia: fatty and menbaraneous deep fascia muscle Extra peritoneal tissue- endoabdominal fascia peritoneum

8. LAYERS OF ANTERIOR ABDOMINAL WALL 1. Skin Shows ‘creases' which represent the lines of orientation of collagen fibres in the dermis- Langer's lines. These lines are surgically important – incisions along them heal better leaving a thin scar; while those across them leave big scars. In pregnant women, obese people and those with abdominal distention from whatever cause, there are dark elongate lines called striae gravidara . The skin is very sensitive to touch, and quickly when touched, the muscles contract.  

9. 2.Superficial fascia Consists of two layers below umbilicus; Fatty layer (Camper's fascia) containing variable amounts of fat, more in females and in the lower abdomen. Membranous layer ( Scarpa's fascia). (+) Contains fibrous tissue and very little fat. (+) Fuses with fascia lata below inguinal ligament) (+) Continuous with the superficial perineal fascia ( Colle's fascia) and with that investing the scrotum and penis. - boundaries, Holdensline , Fournier’s gangrene 3. Deep fascia Deep fascia is thin and invests the muscles/ bone

10. 4. The muscles There are 4 main muscles to note: External oblique Internal oblique Transversus abdominis Rectus abdominis All muscles are derived from the hypomere  

11. MUSCLES Anterior Group Lateral Group Rectus Abdominis Pyramidalis External Oblique Internal Oblique Transversus

12. Linea Alba Fibrous band that extends from symphysis pubis to the xiphoid process and lies in the midline. Fusion of the aponeuroses of the muscles of the anterior abdominal wall and is represented on the surface by a slight median groove

13. LINEA ALBA

14. Linea Semilunaris Lateral edge of the rectus abdominis muscle, crosses the costal margin at the tip of the ninth costal cartilage To accentuate, the patient is asked to lie on his back and raise his shoulders off the couch without using his arms

15. Flat muscles

16. External Oblique Abdominis

17. External Oblique Origin – lower eight ribs Insertion – xiphoid process, linea alba, pubic crest, iliac crest, the pubic tubercle and the anterior superior iliac spine as the inguinal ligament fibers run anterior and inferior (your hands in outside pockets). Nerve supply – lower 6 thoracic nerves Action – supports abdominal contents, assists in forced expiration, micturition, defecation, partuition , vomiting

18. Oblique Internal Abdominis

19. Internal Oblique Origin – thoracolumbar fascia, iliac crest, lateral two thirds of the inguinal ligament Insertion – Lower three ribs and costal cartilages, xiphoid process, linea alba, symphysis pubis, pecten pubis via the conjoint tendon fibers run at right angles to the external oblique (hands in inside pockets), Nerve supply – lower six thoracic nerves Action – same with external obliques

20. Inguinal ligament Muscular part of transversus abdominis Transversus abdominis aponeurosis Muscular part of internal oblique Internal oblique aponeurosis Transversalis fascia Cremasteric fascia forming middle coating of spermatic cord Pubic tubercle

21. Transversus Abdominis

22. Transversus Abdominis Origin – lower six costal cartilages, thoracolumbar fascia, iliac crest, lateral third of inguinal ligament Insertion – xiphoid process, linea alba, symphysis pubis , pecten pubis via the conjoint tendon fibers run transversely Nerve supply – lower six thoracic nerves Action – compresses abdominal contents

23. Rectus abdominis The rectus abdominis is covered by a sheath.

24. RECTUS ABDOMINIS Tendinous Intersection (3) Linea Semilunaris

25. Rectus Abdominis Origin – symphysis pubis and pubic crest Insertion – fifth, sixth and seventh costal cartilages and xiphoid process Nerve supply – lower six thoracic nerves Action – compresses abdominal contents and flexes vertebral column

26. Pyramidalis Origin – anterior surface of pubis Insertion – Linea alba Nerve supply – Twelfth thoracic nerve Action – tenses the linea alba It is often absent in approximately 20% of people Surgeons use the attachment of the pyramidalis to the linea alba as a landmark for an accurate median abdominal incision

27. PYRAMIDALIS

28. Functions of the muscles Support and protection for abdominal viscera Movement of the trunk – flexion, extension, twisting and lateral bending. Maintenance of     posture Increase intra abdominal pressure in functions such as defecation, micturition and parturition etc.  

29. THE RECTUS SHEATH Location Fibrous compartment for rectus abdominis muscle in the paramedian abdominal wall.s Formation Formed of the aponeurosis of abdominal muscles. Proximal 1/3rd The anterior layer joins the aponeurosis of the external oblique to form the anterior wall of the rectus sheath. The posterior layer joins with the aponeurosis of the transversus abdominis to form the posterior wall of the rectus sheath.   Middle 1/3 rd Aponeurosis of internal oblique joins external oblique aponeurosis to form anterior wall. Posterior wall is formed by aponeurosis of transversus abdominis muscle Distal 1/3 rd Mid way between umbilicus and pubic crest all three aponeurosis form the anterior layer The posterior layer is formed only by fascia transversalis

30. Rectus sheath Anterior layer- derived from the External oblique abdominis and anterior layer of the Internal Oblique Abdominis Posterior layer- formed from the aponeurosis of the Internal Oblique Abdominis and Transverse Abdominis. Below the arcuate line, all three flat muscles contribute to the anterior portion of the rectus sheath and there is no posterior component. At and below the arcuate line, Rectus abdominis muscle lies entirely on the transversalis fascia. The rectus sheath is connected by tendinous intersections representing embryologic segmentation. Antagonist- erector spinae complex Strong extensors of the vertebral column.

31. Note: The anterior and posterior layers fuse in the midline to form the linear alba , a fibrous intersection extending from the xiphoid process to the pubic symphysis . The inferior ¼ of the rectus sheath is deficient posteriorly. The limit of the posterior wall is marked by the arcuate line The superior ¾ , posterior wallis covered by aponeurotic sheath The lateral margin of rectus sheath is called linea semilunaris

32. Rectus sheath Above the arcuate line the rectus sheath has two layers an anterior layer a posterior layer

33. Rectus Sheath

34. Arcuate line

35. Arteries 5 intercostal arteries subcostal arteries 4 lumbar arteries Superior epigastric artery—internal thoracic artery Inferior epigastric artery -external iliac artery Deep iliac circumflex artery- external iliac artery

36. Contents of Rectus Sheath Rectus abdominis muscle Inferior and superior epigastric vessels Terminal parts of the lower five intercostal nerves, and the Subcostal nerve. Fibro fatty connective tissue Occasionally lymph node(s)

37. Extra peritoneal fascia Transparent ‘membrane' which lines the inside of the abdominal wall, lying between the parietal peritoneum and the transversalis fascia Its parts are named according to what it lines e.g. (+) diaphragmatic fascia; (+) iliac fascia; (+) Psoas fascia. (+) fascia transversalis ( part covering the muscle transversus abdominis ).

38. Extraperitoneal Fascia

39. Blood supply to the anterior abdominal wall ARTERIES Inferior epigastric : External iliac Superficial circumflex iliac : Femoral arterty Deep circumflex iliac : femoral artery Superior epigastric : internal thoracic Lower intercostal :  Abdominal Aorta Subcostal arteries : Abdominal aorta VEINS The veins correspond to the arteries, but: Inferior epigastric vein anastomoses with lateral thoracic vein. Superficial epigastric vein anastomoses with lateral thoracic vein. These two unite the veins of the upper and lower halves of the body (of the azygous system).

40. SUPERFICIAL ARTERIES Lateral Posterior intercostal a. Subcostal a. Lumbar a. Median Epigastric a. hypogastric a. Inferior Superficial epigastric a. Superficial iliac a.

41. Arteries 5 intercostal arteries subcostal arteries 4 lumbar arteries Superior epigastric artery—internal thoracic artery Inferior epigastric artery -external iliac artery Deep iliac circumflex artery- external iliac artery

42. Arteries of the Anterior and Lateral Abdominal Walls Superior epigastric artery – terminal branch of the internal thoracic artery; supplies the upper central part of the anterior abdominal wall Inferior epigastric artery – branch of the external iliac artery, just above the inguinal ligament; supplies the lower central part of the anterior abdominal wall

43. Deep circumflex iliac artery – branch of the external iliac artery; supplies the lower lateral part of the abdominal wall. Posterior Intercostal arteries – 2, branches of the descending thoracic aorta; supply the lateral part of the abdominal wall.

44. Superficial veins subclavian femoral paraumbilical S epigastric S circumflex iliac thoracoepigastric lateral thoracic portal

45. Lymphatic Drainage Anterior → Intercostal Lymphatic Nodes Parasternal Lymphatic Nodes Middle → Lumbar Lymphatic Nodes Lower → External Iliac Lymphatic Nodes

46. Lymphatic Drainage Superior to the umbilical level: Axillary nodes Parasternal nodes Inferior to the umbilical level: Superficial Inguinal lymph nodes Deep inguinal nodes External iliac nodes Lumbar nodes Innervation Ventral rami of lower 6 thoracic nerves. T7-T9 supply region above umbilicus T11-L1 below umbilicus T10 skin around umbilicus The lower intercostals and subcostal Segmental with T10 Para umbilical.

47. Innervation T7-12 thoracic n. Iliohypogastric n. Ilioinguinal n. Genitofemoral n.

48. Innervation Intercostal n. Anterior cutaneous branch Lateral cutaneous branch

49. The internal surface of anterior abdominal wall In the midline, there are elevations of peritoneum with free edges, called folds. Superior to the umbilicus: A median fold, the falciform ligament . This contains the ligamentum teres , the obliterated umbilical vein. Note that the umbilical vein is patent for sometime after birth and may be used for exchange transfusion. Inferior to the umbilicus, there are 5 folds: The median umbilical fold is due to median umbilical ligament , the remnant of the urachus , which develops from the allantois . It attaches to the urinary bladder. 2 medial umbilical folds formed by medial umbilical ligaments – the obliterated umbilical arteries. 2 lateral umbilical folds – formed by the inferior epigastric vessels

50. Abdominal wall Dr.G.Bhanu Prakash www.gims-org.com

51. Inguinal Ligament Rolled-under inferior margin of the external oblique muscle Attached laterally to the ASIS, curves downward and medially to be attached to the pubic tubercle

52. Superficial Inguinal Ring Triangular aperture in the aponeurosis of the external oblique muscle situated above and medial to the pubic tubercle In males – the margins can be felt by invaginating the skin of the upper part of the scrotum with the tip of the little finger In females – smaller and difficult to palpate

53. Cremaster Conjoint Tendon

54. Conjoint Tendon Cremaster

55. Transverse Abdominal Fascia abdominal inguinal ring (deep inguinal ring)

56. Superficial Inguinal Ring Medial Crus Lateral Crus Intercrural Fibers Reflected Ligament

57. The inguinal canal Canal represents path taken by testis out of the abdomen. BOUNDARIES Floor: Inguinal ligament and lacunar ligament Roof: Arching fibres of internal oblique and transversus abdominis. Antero lateral: Aponeurosis of external oblique Posterior: Fascia transversalis laterally and conjoint tendon medially (of transversus and internal oblique abdominal muscles) CONTENTS Spermatic cord in male Round ligament of uterus in female and its artery Ilioinguinal nerve It may contain: Iliohypogastric nerve Genitofemoral nerve (genital branch) Subcostal (in the upper part)   Inguinal Rings Testis Ductus deferens Pampiniform plexus Testicular artery Cremasteric artery Spermatic cord Aponeurosis of internal oblique External oblique

58. Inguinal Rings Superficial ring is a triangular aperture in the aponeurosis of the external oblique muscle. (+) Base: pubic crest (+) Sides: crura of the external oblique aponeurosis. The deep ring is a deficit in transversalis fascia, lateral to inferior epigastric artery.  

59. Inguinal triangle Bounded by: Medially: Linear semilunaris (lateral edge of Rectus abdomis ) Inferiorly: Inguinal ligament Supero -laterally: Inferior epigastric artery

60. Boundaries

61. Inguinal Triangle ( Hesselbach's triangle ) Direct Hernia

62. Spermatic Cord Comprises of structures running to and from the testis, surrounded by structures derived from the anterior abdominal wall. Traverses entire inguinal canal Coverings Internal spermatic fascia - from transversalis fascia Cremasteric fascia - from fascia of internal oblique Cremaster muscle - from internal oblique abdomen External spermatic fascia - from external oblique Contents Autonomic nerve plexus Testicular artery; artery to ductus deferens, cremasteric artery Pampiniform plexus of veins Ductus deferens Lymph vessels Remnants of processus vaginalis

63. Cremasteric reflex Genital branch of genitofemoral nerve supply cremasteric muscle. Stroking the area of supply of the femoral branch ( superomedial thigh) stimulates the muscle, pulling up the testis – this is the cremasteric reflex. Easy to demonstrate in children, but gets weaker with age.

64. Incisions

65.    PARAMEDIAN Usually, the rectus abdominis is retracted laterally , to avoid detaching its nerve and vessels. It is unwise to cut the muscle longitudinally. These incisions, do not meet many blood vessels. The epigastric vessels (inferior and superior) are usually easy to identify.

66. HORIZONTAL INCISION Especially in the lower abdomen ( Pfanesteil ) may encounter the inferior and superficial epigastric vessels. If these can be guarded, handled, the incision heals rapidly, leaving thin scars. GRIDIRON INCISION   It is mentioned under appendix.

67. Review Questions Describe the muscles, blood supply, lymphatic drainage and sensory innervation of the anterior abdominal wall Discuss the formation and contents of the inguinal canal. Add notes on the distinction between direct and indirect inguinal hernias. List six structures that must be safeguarded during hernial repair Describe the formation and contents of the rectus sheath Outline the general organization of the superficial fascia of the anterior abdominal wall, and the perineum. Add clinical notes on the implication of this organization Describe in detail the pattern and clinical significance of the blood supply of the anterior abdominal wall. State the advantages and disadvantages of the various incisions in the anterior abdominal wall.

68. Abdominal wall herniae