1. The Abdomen Lee liyingchd@163.com
HUMAN ANATOMY
The Abdomen
Lee

2. Overview Five weeks in learning (including presetation and practice)
Preview and review
Be sure to come on time, 1: 20pm Monday
Dissecting is the best way in learning anatomy; try to use your hands more; cooperation---team work
Paper works after classes (maybe twice)
Quizs in class
Mark your dissecting skills .

3. Textbook: References：
ESSENTIAL CLINICAL ANATOMY 4th Keith Moore.
References：
Grant’s Dissector  12th        Eberhard K. sauerland (Text book)
Clinical Anatomy for Medical Students, 7th Edition, Richard Snell, Lippincott
Atlas of Human Anatomy, 4th Edition, Frank Netter (3rd Ed is also suitable)
Grant's Atlas of Anatomy, 11th Edition, Agur & Lee, Williams & Wilkins
Taber's Cyclopedic Medical Dictionary (Recommended)

4. The abdomen Ⅰ Introduction
the abdominal wall
the abdominal cavity
visceral organs
Key points:
1. layers of the
anterolateral abdominal wall;
2.Inguinal Region &Inguinal canal
◆Clinical significance
1. know the abdominal incisions,
2. Identify the direct and indirect inguinal hernia

5. Digestive System Organization
Gastrointestinal (Gl) tract (Alimentary canal)
Tube within a tube
Direct link/path between organs
Structures
Mouth
Oral Cavity
Pharynx
Esophagus
Stomach
Duedenum
Jejenum
IIleum
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anus

6. The abdominal wall 1. Surface landmarks
Boundaries, Planes and regions
2. Anterolateral abdominal wall
1. Muscles
2. Blood vessels and lymphatic drainage
3. Nerves
3. Inguinal region and inguinal canal
1.1 Body landmarks
Xiphoid process
Costal arch
Anterior superior iliac spine “ASIS”
Iliac crest ( tubercle 5cm from asis)
Superior border of pubic symphysis
Pubic tubercle

7. Boundaries of the abdomen
Boundary
Superiorly－
xiphoid process①, lower border of costal arch ② ③, 11th and 12th ribs, vertebra T12
Inferiorly－
superior border of pubic symphysis⒀,
pubic crest⑿, pubic tubercle⑾,
fold of inguinal canal,
anterior superior iliac spine ASIS⑦,
iliac crest ⑥, spinous process of L5

8. The abdominal regions ——Nine regions
Epigastric region
R. hypochondriac region
L. hypochondriac region
R. lateral regions
L. lateral regions
R. inguinal region
Umbilical region
L. inguinal region
Hypogastric(Pubic) region
2 horizontal planes: subcostal and transtubercular planes
2 vertical planes--- line joins the midclavicular to midpoint of inguinal canal

9. The abdominal regions ——Four quadrants
Left and right upper quadrants
Left and right lower quadrants
The median plane and the transverse umbilicus plane

10. Landmarks of abdomen Pubic symphysis Pubic tubercle Iliac crest
Umbilicus
Linea semilunaris
Transpyloric plane L1
First layer－liver, gallbladder, stomach
Second layer－duodenum, pancreas, spleen
Third layer－suprarenal gland, kidney, ureter, inferior vena cava, abdominal aorta, nerves and lymphatics

11. Relations of abdominal viscera
First layer－liver, gallbladder, stomach
Second layer－duodenum, pancreas, spleen
Third layer－suprarenal gland, kidney, ureter, inferior vena cava, abdominal aorta, nerves and lymphatics

12. Anterolateral abdominal wall
9. Layers ( from superficial to deep)
Skin
Superficial fascia (2layers below umbilicus)
Deep fascia
Anterolateral muscles(3 layers of paired m,)
Transversalis fascia
Extraperitoneal fascia
Parietal peritoneum

13. Anterolateral abdominal wall
1st . Skin
2nd .Superficial fascia
Fatty layer (Camper’s fascia) continuous with the superficial fascia over the rest of the body.
Membranous layer (Scarpa’s fascia) below umbilicus
passes over the inguinal ligament to fuse the deep fascia of the thigh (fascia lata).
In the perineum, it is attaches on each side to the margins of the pubic arch and is know as Colles’ fascia.
3rd . Investing fascia (deep fascia)

14. Superficial vessels and cutaneous nerves
Arteries
Superficial epigastric a.
Superficial iliac circumflex a.
Veins
Thoracoepigastric v.
Superficial epigastric v.
Cutaneous nerves (multi_segmental )
Anterior and lateral cutaneous branches of T 7~11 nerves
the subcostal nerves T12
Iliohypogastric n. ←L1
ilio-inguinal n. ← L1

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

16. Muscles of abdomen

17. Muscles of abdomen Anterolateral group 4 bilateral paired muscles
External oblique abdominis
internal oblique abdominis
Transverse abdominis
Rectus abdominis

18. Muscles of abdomen Posterior group Quadratus lumborum Psoas major
iliacus
The combined muscle (iliopsoas) is inserted into the lesser trochanter of the femur. iliopsoas is the main flexor of the thigh and trunk

19. 4th . external oblique abdominis
General direction of fibers: inferior and anterior ;run downward and inward.
The aponeurosis of the external oblique muscle passes anterior to the rectus abdominis
and forms the anterior layer of the rectus sheath.

20. external oblique abdominis
Structures
Inguinal ligament ----the inferior edge of the aponeurosis of external oblique, extends from the anterior superior iliac spine to the pubic tubercle . Thickened and curved.
Lacunar ligament ---- A part of the aponeourosis continues posterior pubic tubercle toward the superior pubic ramus is termed the lacunar ligament.
Pectineal ligament

21. Superficial inguinal ring
Superficial inguinal ring －triangular-shaped defect in aponeurosis of external oblique abdominis above pubic tubercle;
medial and lateral crus; intercural fibers

22. 5th .internal oblique abdominis
Deep to external oblique abdominis
General direction of fibres: upwards, forwards and medially
The aponeurosis of the internal oblique muscle divides into anterior and posterior layers,to form anterior and posterior layers of the rectus sheath.

23. 6th .Transversus abdominis
Deep to internal oblique abdominis
General direction of fibers: run horizontally forward.
The aponeurosis of this muscle contributes to the rectus sheath.

24. Transversus abdominis
Inguinal falx(conjoint tendon)
internal oblique abdominis
has a lower, free border that arches over spermatic cord
Inserted with transversus abdominis fiber into medial part of pecten of pubis
Cremaster
Dirived from the lower fibers of the internal oblique abdominis
and transversus abdominis
Around the spermatic cord and testis,

25. Rectus abdominis Position: lie on to either of midline
Origin: pubic crest and symphysis
Insertion: xiphoid and 5th-7th costal cartilages
Tendinous intersections 3-4
linea semiluaris
Linea alba

26. 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 expiration.
Flex, lateral flex, and rotate vertebral column

27. Sheath of rectus abdominis
Anterior layer
Formed by fusion of aponeurosis of external oblique ;
anterior leaf of aponeurosis of internal oblique
Posterior layer
posterior leaf of internal oblique and transversus aponeurosis
arcuate line ---- the aponeuroses of all three muscles pass anterior to the rectus muscles to reach the linea alba ,about 4-5cm below the umbilicus ; the lower free border is arcuate line.
Below this line rectus abdominis in contact with transverse fascia

28. Sheath of rectus abdominis

29. anterior abdominal wall
1。skin
2。Camper fascia
3。Scarpa fascia
4. Anterior layer of
rectus sheath
5.Rectus abdominis
6. Posterior layer of
7.Transversalis fascia
8. Extraperitoneal fascia
9. Parietal peritoneum

30. Muscles of abdomen Linea alba .
－The linea alba is a midline raphe,forming by the aponeuroses of the abdominal muscles, extending vertically from the xiphoid process to the pubic symphysis. a median incision through the linea alba is a common surgical approach in acute abdomen. .

31. Deep vessels of abdomen
Arteries
Superior and inferior epigastric arteris
Inferior branch of posterior intercostal a.
Subcostal a.
Deep iliac circumflex a.
Four lumbar a.
Nerves
Subcostal nerve
Iliohypogastric nerve
Ilioinguinal nerve

32. Deep nerves of abdomen Lower five intercostals nerves Subcostal nerve
Iliohypogastric n.
Ilioinguinal n.
Run between internal oblique and tranversus abdominis.
Lateral femoral cutaneous n.

33. Deep nerves of abdomen Iliohypogastric n. Arises from lumbar plexusL1
Passes forward between internal oblique and tranversus abdominis
Pierces internal oblique 2.5 cm medial to ASIS
Pierces aponeurosis of external oblique about 2.5 cm above superficial inguinal ring

34. Deep nerves of abdomen Ilioinguinal n. Arises from lumbar plexusL1
Runs parallel and inferior to the iliohypogastric n.
Enters inguinal canal and exits through superficial inguinal ring
Supplies the three flat muscles. It also supplies the skin just above the pubis symphysis and the scrotum ( greater lip of pudendum).

35. ※7th . Transversalis fascia--- deep inguinal ring iliopubic tract
※8th .Extraperitoneal fascia

36. The peritoneum
is a continuous, transparent serous membrane lining the abdominopelvic wall , and covers the organs .
Parietal peritoneum
Sensitive,supplied by somatic N,
Pain from it is well localized .
Visceral peritoneum
Insensitive,supplied by visceral N,
Pain is poorly localized
Foregut----epigastric region
Midgut---umbilical
Hindgut---pubic

37. Parietal peritoneum 5 folds ※ 3 paired peritoneal fossae
1.Median umbilical fold—remnant of urachus
2.Medial umbilical folds---umbilical artery
3.Lateral umbilical folds---inferior epigastric vessles
※ 3 paired peritoneal fossae
1.Supravesicle fossae
2.Median inguinal fossea
=Inguinal Triangle (of Hesselbach)
3.Lateral inguinal fossae

38. Anterolateral abdominal wall
Layers ( from superficial to deep)
1.Skin
2. 3。Superficial fascia
Anterolateral muscles
7.Transversalis fascia
8.Extraperitoneal fascia
9.Parietal peritoneum

39. Inguinal region Boundaries The area extends between ASIS
to pubic tubercle
Exit and enter structures
weakness ?
inguinal ligament
inguinal canal
inguinal triangle

40. Inguinal canal
Position: oblique passage, 4cm long, begins at the deep inguinal ring and terminates at the superficial inguinal ring .located 1.5cm above medial half of inguinal ligament .Transmits the spermatic cord or the round ligament of the uterus and the ilioinguinal nerve .an indirect hernia(if presents) passes the canal .

41. Boundaries of inguinal canal
Anterior wall
Aponeurosis of external oblique abdominis and internal oblique abdominis
Posterior wall
Transversalis fascia
Aponeurosis of transverse abdominis
Roof－arching fibers of internal oblique and transverse abdominis
Floor－inguinal ligament

42. Boundaries of inguinal canal
Two openings
Superfacial inguinal ring －a triangular-shaped defect in the aponeurosis of the external oblique a, just lateral to the pubic tubercle
Deep inguinal ring－lies in transversalis fascia ,just lateral to the inferior epigastric vessels .

43. openings：
Superficial inguinal ring
Deep inguinal ring

44. 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 internal oblique 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.

45. Structures passing through the inguinal canal
In males
Spermatic cord
Ilioinguinal nerve
In females
Round ligament of uterus
ilioinguinal nerve

46. Spermatic cord contents of spermatic cord :
Spermatic cord----cord-like structure in males formed by the ductus deferens and surrounding tissues, run from the abdomen to testis.
contents of spermatic cord :
3 arteries: artery to ductus deferens, testicular artery, cremasteric artery;
3 fascial layers: external spermatic, cremasteric, and internal spermatic fascia;
3 other structures: pampiniform venous plexus, ductus deferens, testicular lymphatics;
3 nerves: genital branch of the genitofemoral nerve , autonomic and visceral afferent fibres, ilioinguinal nerve.
Testis: male gonad
Epididymis:
Scrotum:

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

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

49. Descent of testes Newborn
Congenital cryptorchidism (Undescended testis)

50. Inguinal Triangle (of Hesselbach)
Boundaries
Medially: Lateral border of rectus abdominis
Laterally: Inferior epigastric artery
Inferiorly: Inguinal ligament

51. Inguinal canal
The inguinal canal is an oblique passage through the abdominal wall.
About 3 to 5 cm long.
Occupied by the spermatic cord or by the round ligament of the uterus, also contains the ilioinguinal nerve.
2 RINGS
The superficial inguinal ring is a triangular opening in the aponeurosis of the external oblique muscle.
The deep inguinal ring is a slit-like opening in the transversalis fascia
4 WALLS
Anterior : the aponeurosis of the external oblique muscle , laterally, by internal oblique .
Posterior: formed by the transversalis fascia ; the aponeurosis of the internal oblique transversus abdominis muscle, come together to the pubic attachments into conjoint tendon (inguinal falx).
Superior: lateral--- transversalis fascia ;central---the arching fibers of the internal oblique muscle and the transversus abdominis muscle, media---the medial crus.
Floor :the inguinal and lacunar ligaments.
The canal is potentially a weak area through which an inguinal hernia may occur.

52. Indirect inguinal hernia and direct inguinal hernia
Inguinal hernia is a protrusion of peritoneum(or~) through a weakness in the abdominal wall in the region of the inguinal canal.

53. A direct inguinal hernia results from a weakness of the posterior wall of the inguinal canal and herniation occurs medial to the inferior epigastric vessels .
An indirect inguinal hernia arises lateral to the inferior epigastric vessels, the protrusion following the path of the spermatic cord or round ligament through the deep inguinal ring into the inguinal canal. With an indirect inguinal hernia bowel can easily pass down the inguinal canal into the scrotum

54. Femoral hernia is a protrusion of a loop of the intestine through the femoral canal located in the lower groin near the thigh, with the hernial neck lying below and lateral to the pubic tubercle. Common in women --- over weight , have had several children. Strangulation(constriction) of a hernia is an acute surgical emergency

55. The pectineal and lacunar ligaments are often used as anchor points for sutures.

56. Inguinal hernia repair

57. Anterior abdominal wall
Transverse fascia
Extraperitoneal fascia
Parietal peritoneum

58. question? How many layers are there in each part of abdominal wall?
median incision
McBurney incisions

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

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

61. question 2.What are the boundaries of the inguinal triangle?
1. What is the inguinal ligament?
The inguinal ligament is the thichened lower edge of the external oblique aponeurosis. It extends from the anterior superior iliac spine to the pubic tubercle.
Medially, a small part is reflected backward to the pubis as ---the lacunar ligament, and its lateral edge limits a gap (lacuna), which forms the medial boundary of a femoral hernia.
A further lateral extension along the pubis and behind the femoral vessels is known as the pectineal ligament .
2.What are the boundaries of the inguinal triangle?
The inguinal triangle is bounded by the inferior epigastric artery, the lateral border of the rectus, and the inguinal ligament. A direct inguinal hernia enters the inguinal canal through the inguinal triangle.

62. New terms Inguinal ligament Superficial (deep)inguinal ring
Transversus abdominis
Inguinal canal
Rectus abdominis
Tendinous intersections
rectus sheath
arcuate line
inferior epigastric artery
Intercostals nerve
Iliohypogastric n.
Ilioinguinal n.
Spermatic cord
Hernia (herniation)

63. The struggle you’re in today is developing the strength you need for tomorrow.
Don’t give up.