Abdominal anatomy- The abdominal wall, inguinal canal and ailimentary tract

Question 1

lymph drainage from GIT

Answer 1

lymphoid follicle in mucosa –> juxtaintestinal nodes in small intestine and paracolic in large at teh gut margins –> nodes along the major blood vessels –> preaortic group (coeliac, superior mesenteric and inferior mesenteric)–> preaortic mesenterics coeliac group –> cisterna chyli

Question 2

Nervous System supply to GIT

Answer 2

• parasympathetic and sympathetic fibres

- intrinsic from Myenteric plexus of Auerbach and Submucosal plexus of Meissner

Question 3

Passage of Oesophagus

Answer 3

• enters at T10 through oesophageal hiatus
• it is invested in peritoneum to the right by teh upper part of the lesser omentum and to teh right by the greater omentum
• enters the cardiac orifice
• anterior and posterior vagal trunks lie respectively

Question 4

Parts of the stomach

Answer 4

• fundus: lies above the cardia
• body: from the fundsu to the angular notch at the lower part of the lesser curvature
• pyloric part: from the angular notch to the gastroduodenal junction
• • 2 parts: pyloric antrum and pyloric canal

Question 5

The prepyloric vein

Answer 5

The pyeloric sphincter is indicated on the anterior surface by the prepyloric vein

Question 6

structures in the stomach bed

Answer 6

• the bed is covered by the posterior wall of the lesser sac
• on the right is the left crus of the diaphragm
• in the middle is the upper pole of the left kidney - this lies in a triangle formed by the pancreas running transverse, lateral the spleen and medial suprarenal
• to the right of the lesser curvature - is the aorta, with coeliac trunk coming off

Question 7

arterial supply to the stomach

Answer 7

• right and left gastric anastomose in lesser curvature
• right and left gastro-epiploic artery anastomose in greater curvature and supply the greater omentum
• fundus - by 5-6 short gastric arteries off the splenic artery - running in the gastrosplenic ligament
• all vessel branches are at right angles (opposed to the oblique branches of the vagus)

Question 8

venous supply of the stomach

Answer 8

• veins accompany the arteries and drain into the splenic or superior mesenteric or portal veins
• Prepyloric vein – drains into portal or right gastric vein

Question 9

Lymph drainage to the stomach

Answer 9

• all eventually drain to coeliac nodes. All vessels freely anastamose but valves control direction of flow
• Flow as follows:
  o Drawing a line parallel to the greater curvature and 2/3rds of the way down the stomach
   Above this line lymph passes into the left and right gastric nodes along the lesser curvature adjacent to the corresponding left and right gastric arteries
   Along the upper left quadrant below the line – lymph flows to the splenic nodes at the hilum, which in turn drain into the pancreatic nodes
   From the right and below the line the rest of the nodes drain into the gastroepiploic vessels along the greater curvature

Question 10

mechanism of Troisiers sign in gastric cancer

Answer 10

Troisiers sign (left supraclavicular node) occurs presumably though spread into the posterior mediastinum in gastric ca

Question 11

Nervous supply to the stomach

Answer 11

• sympathetic and afferent pains- follows arterial supply

- parasympathetic - via vagus - anterior and posterior vagal trunks

Question 12

Vagal trunks and path at the stomach

Answer 12

The anterior vagal trunk lies in contact the with anterior oesophageal wall, just off to the right after it passes through the diaphragm. It runs down the lesser curvature with the left gastric, giving off branches to the anterior stomach wall
 It also gives off a hepatic branch, which then gives off a branch to the pyloric antrum
 In 20% it is double
The posterior vagal trunk lies in loose tissue behind and to the right of the oesophagus, not in contact with it. It runs in the lesser omentum behind the anterior trunk, giving off a large coeliac branch , that runs backwards along the left gastric artery to the coeliac ganglion.
 Branches supply the posterior stomach wall

Question 13

vagotomy types

Answer 13

o Truncal vagotomy: cuts at the level of the oesophagus
o Selective vagotomy: cut branches that run from the nerves in the lesser curvature – can identify as they run obliquely, compared to artery which run at right angles
o High selective vagotomy: cuts nerves only to the fundus and body (not antrum- avoiding problems with stasis

Question 14

Parts of the duodenum

Answer 14

- first 2cm is intraperitoneal, rest is retroperitoneal 
4 parts 
1) superior – 2 inch long 
2) descending – 3inch long
3) horizontal – 4inch long
4) ascending – 1inch long 
- 25cm long 
Forms a c shaped loop around the head of the pancreas at L2  1ts part at L1, 2nd at L2, 3rd at L3 and 4th at L2

Question 15

features and relations of the first part of the duodenum

Answer 15

The first part: runs right, upwards and backwards from the pylorus
o The first 2cm is the duodenal cap and lies in the lesser and greater omentum and forms the lower borer of the epiploic foramen. It also lies on the upon the liver pedicle (bile duct, hepatic artery and portal vein), and behind this lies IVC at the epiploic foramen
 The neck of the gallbladder touches the upper convexity of the duodenal cap
The next 3cm is retroperitoneal and runs back and upwards on the right crus of the diaphragm and right psoas to the medial kidney border
 It also touches the upper part of the head of the pancreas and is covered in front by peritoneum

Question 16

features and relations of the second part of the duodenum

Answer 16

The second part curves down over the hilum of the right kidney. And lies along the head of the pancreas
o It is crossed by the attachment of the transverse mesocolon so that the upper half is in the supracolic compartment, to the left of the hepatorenal pouch and the lower is the infracolic compartment medial to the lower pole of the right kidney
o Its posteromedial wall receives the bile duct and main pancreatic duct at the Ampulla of Vater, which opens into the duodenum at the major duodenal papilla 10cm from the pylorus
o 2cm proximal from this is the opening of the accessory pancreatic duct to the minor dudodenal papilla

Question 17

Features and relations of the third part of the duodenum

Answer 17

The third part curves forward from the right paravertebral gutter over the slope of the right psoas muscle with the gonadal vessels and ureter intervening, projecting over the IVC and aorta to reach the left psoas muscle
o Its inferior border lies on the aorta at the commencement of the inferior mesenteric artery @ the level of the umbilicus at L3/4
o Its upper border hugs the lower border of the pancreas
o It is crossed by the SMA and the root of the mesentery (as it travels obliquely and down)
 as it is crossed by the mesentery root it lies in the right and left infracolic compartmnets

Question 18

features and relations of the fourth part of the duodenum

Answer 18

The fourth part ascends to the left of the aorta, lying on the left posas muscle and left lumbar sympathetic trunks to reach the lower border of the pancreas, almost as high as the root of the transverse mesocolon at L2
o It is covered by the peritoneal floor of the left infracolic compartment, where the jejunum lies on top, it breaks free of this peritoneum and curves forwards and up to the right as the duodenojejunal flexure
 In doing so the duodenum pulls a double sheet of peritoneum up – the mesentry of the small bowel which then slopes over the third part of the duodenum
o The duodenojejunal flexure is fixed to the left psoas by the suspensory muscle of the duodenum (Ligament of Treitz) – Its path descends from the right crus of the diaphragm in front of the aorta, behind the pancreas but in front of the renal vessels and blends with the outer muscle layer of the flexure

Question 19

paraduodenal recesses

Answer 19

are 4 folds in the peritoneum that lie to the left of the duodenojejunal flexure
1) paraduodenal recess proper- Is a small invagination beneath the upper end of the inferior mesenteric vein – an incarcerated internal hernia at this point may obstruct and thrombose the vein – also danger in damaging the vein in surgery for the hernia
2 + 3) superior and inferior duodenal recesses
4) retroduodenal recess (fossae) - evacuated behind the curvature of the flexure- often called a fossae
- mouths of all 4 face inwards

Question 20

Blood supply of the duodenum

Answer 20

• In the first 2cm however – it receives small branches from a variety of sources- hepatic, common hepatic, gastroduodenal, superior pancreaticoduodenal, right gastric and right gastroepiploic—this is where duodenal ulcers occur
• otherwise - superior and inferior pancreaticoduodenal arteries supply

Question 21

venous supply of the duodenum

Answer 21

follows corresponding arteries

Question 22

lymph node drainage of the duodenum

Answer 22

Nodes that accompany the superior and inferior pancreaticoduodenal arteries–> respective coeliac and superior mesenteric nodes

Question 23

differences between jejunum and ileum

Answer 23

1) jejunum is thicker walled and wider bored - can detect by rolling between fingers
2) peyers patches in ileum - on antemesenteric border in the ileum
3) arterial structure
4) jejunum lies in the upper part of the infracolic compartment, the ileum lies in the lower part and in the pelvis

Question 24

meckel’s diverticulum

Answer 24

Meckels diverticul – lies 2 feet (60cm) from the caecum, is 2inches (5cm) long and present in 2%
o May be a blind end, contain gastic, pancreatic or liver tissue
o Represents the vitellointestinal duct  its apex may be attached to the umbilicus directly or via a fibrous cord

Question 25

Blood supply of ileum and jejunum

Answer 25

• ielal and jejunal branches arise from the SMA and enter the mesentery at the root
  •The jejunal branches anastomose with each other to from the arterial arcades, they are single in the jejunum high up and double lower down
  oStraight arteries then pass to the mesenteric border of the gut
   these straight vessels pass on one side of the gut wall and sink into it
  Occlusion of a straight artery will lead to segmental necrosis as they are end arteries, but arterial arcade occlusion will not affect it
  o as the mesenteric fat is thin the straight arteries form visible “windows”
  • Ileal arteries are similar- although they have 3-5 arcades, with the most distal lying near the wall so that their straight arteries are short
  o Windows are not seen due to thicker mesenteric fat
  •The SMA supplies the region of the ileal diverticulum (if present) and anastomoses with the arcade and ileocolic artery to supply there terminal ileum

Question 26

lymph drainage of ileum and jejunum

Answer 26

Into Superior mesenteric group

Question 27

nerve supply to the small bowel

Answer 27

• Parasympathetic supply – travels with arterial supply to augment peristalsis
• Sympathetic supply – lateral horn cells of T9 and 10 – vasoconstriction and inhibit peristalsis - pain in umbilical region

Question 28

blood supply of caecum

Answer 28

• Blood supply: anterior and posterior caecal arteries
o Anterior is smaller and posterior is larger
o Both off the ileocolic artery
o Posterior gives off appendicular artery

Question 29

structure of the retrocaecal recess

Answer 29

•The peritoneum covers front and side and continues up behind and is reflected back down towards the right ilical fossa
oThere are two caecal folds on each side (parietocolic membranes) passing from the caecum to the posterior abdominal wall. The space bound by the this, the caecum anteriorly and the posterior abdominal wall is the retrocaecal recess
oThe vermiform appendix frequently occupies (herniates) this recess when in the retrocaecal position.

Question 30

lymph drainage of caecum

Answer 30

ileocolic artery nodes

Question 31

relations to the caecum

Answer 31

The caecum lies in the RIF over the iliacus and psoas fascia and femoral nerve. Its lower end lies over the pelvic brim

Question 32

locations of taeniae coli in caecum

Answer 32

lie anterior, posteromedial, and posterolateral and coverge at the base of the appendix – they represent the longitudinal muscle of the large bowel

Question 33

mesoappendix origins

Answer 33

mesoappendix is a triangular fold for peritoneum that is a propogation of the left (inferior) layer of the mesentry of the terminal ileum

Question 34

blood supply of the appendix

Answer 34

The appendicular artery off the posterior caecal artery runs in the free margin of the mesoappendix, when it reaches the wall of the appendix it continues along it
oIs an end artery - ischaemic necrosis may result when appendix is inflamed –> perforation

Question 35

The caecal recesses

Answer 35

4x recesses – all mouths face away from each other unlike the paraduodenal recesses
oRetrocaecal
oSuperior ileocaecal recess: lies between the root of the mesentery, anterior wall of the caecum and peritoneum raised by the anterior caecal artery – called the vascular fold of the caecum
oInferior ileocaecal recess: is formed by the caeacum lieing laterally, the floor of the ileum lying superiorly, mesoappendix, And a fold of peritoneum known as the ileocaecal fold – which runs from the terminal ileum to the base of the appendix (this fold was formerly known as the bloodless fold of Treves – which is a misnomer as there are small vessels)
oThere is another recess between the peritoneal floor and meso appendix

Question 36

Relations of the hepatic flexure

Answer 36

lies lateral to the inferior pole of the right kidney, in contact with the surface of the liver

Question 37

relations of the ascending bowel

Answer 37

• 15cm long

- lies on the iliac fascia and the anterior layer of the lumbar fascia, connected to these by fibrous tissue

Question 38

peritoneal structure of the ascending bowel

Answer 38

• Laterally the serous coat runs into the paracolic gutter and medially into the right infracolic compartment
  o Ileocolic and right colic arteries lie beneath the floor of the right infracolic compartment
• If the EMBRYONIC mesentry is maintained – in approx. 10% It carries these arteries

Question 39

locations of the Taeniae coli in ascending bowel

Answer 39

anterior, posteriomedial and posterolateral (like caecum)

Question 40

attachments of the transverse mesocolon

Answer 40

• transverse mesocolon: Inferior pole of R) kidney, across the descending (2nd part of the duodenum), over the pancreas and to the inferior pole of the left kidney
• gastrocolic ligament attaches transverse mesocolon and colon to the greater omentum and greater curvature of the stomach

Question 41

Location of the taeniae coli in transverse bowel

Answer 41

rotation causes the anterior to lies posterior and the posterior to lie anteroinferior and anterosuperior

Question 42

relations of the descending colon

Answer 42

lies on lumbar fascia and iliac fascia – connected to these

Question 43

Embryology of descending colon mesentery

Answer 43

the midline dorsal mesocolon contains left colic vessels- this swing to the left and fuses with the parietal peritoneum of posterior abdominal wall and the right leaf of the dorsal mesocolon forms the floor of the left infracolic compartment
oLeft colic vessels lie immediately beneath it

Question 44

Teniae coli of descending colon

Answer 44

• Three teniae coli lie anterior and posterior-medial and posterior-lateral

Question 45

attachment of sigmoid mesocolon

Answer 45

• Inverted V shaped mesentery base- top of v diverges from the bifurcation of the common iliac
o Lateral limbis attached over the external iliac halfway to the inguinal ligament – 5cm in length
o Medial limb along the posterior abdominal wall to over S3- again is 5cm
o Sigmoid vessels lie in the mesentery

Question 46

Arterial supply of the colon

Answer 46

• Ascending bowel, and proximal 2/3rds of the transverse are supplied by the ileocolic, right colic and middle colic of MSA
• Rest of bowel by left colic and sigmoid branches of inferior mesenteric
• Anastamotic branches between the left colic and middle colic form an arterial circle – often called the margical artery
o Watershed area is here

Question 47

Lymph drainage of the large bowel

Answer 47

follow the blood vessels and drain into the SM and IM nodes

Question 48

nervous supply to the large bowel

Answer 48

• Parasympathetic is from vagus and pelvic splanchnic
• SNS from T10 to L2
• Pain is from vasoconstrictor nerves  periumbilical pain from midgut derivative (appendix) and hypogastric to hindgut
• For rectum  pain from the descending and sigmoid run from parasympathetic nerves

Question 49

Types of colectomy’s

Answer 49

• Right hemicolectomy: terminal ileum to proximal transverse colon, with ligation of right and ileocolic arteries adjacent to SMA
• Transverse colectomy: removal of transverse mesocolon with transverse colon, middle colic vessels and greater omentum
• Left hemicolectomy: left end of transverse mesocolon to part of the sigmoid colon with left colic and sigmoid vessels ligated – may have to remove IMA
• Sigmoid colectomy: lower descending colon to rectum

Question 50

transpyloric plane

Answer 50

midway between the jugular notch and top of the pubic symphysis, crosses the pylorus
- along with midclavicular line and lower transverse -between the two tubercles of the iliac crests (intertubercular plane) - divides the abdomen into 9

Question 51

layers of the abdominal wall

Answer 51

1) skin
2) Campers Fascia (fatty)
3) Scarpa’ fascia (membranous)
4) external oblique
5) internal oblqiue
6) transversus abdominus
7) transversalis fascia
8) extraperitoneal fat
9) parietal peritoneum

Question 52

Origins and insertions of the external oblique

Answer 52

Origins: arises form 8 digitations from the bottom 8 ribs- bottom 4 interdigitate with latissimus dorsi, upper 4 serratus anterior
Insert: the outer lip of the anterior half of the iliac crest, more medially from the anterior iliac spine to the umbilicus is aponeurosis, which inserts from pubic symphysis to the xiphisternum

Question 53

The lumbar triangle (of Petit)

Answer 53

Floor: internal oblique
Margins: a triangle with the iliac crest at the base, latissumus dorsi posteriorly, and external onlique anteriorly as the sides of the traingle

Question 54

Inguinal ligament origins, insertions and structure

Answer 54

• formed from the lower border of external oblique from the anterior superior iliac spine to the pubic tubercle
  Edge is rolled inwards to form origins of the internal oblique and transversus abdominus
  Lower portion attaches to the fascia lata of the thigh

Question 55

The lacunar ligament (of Gibernat)- pelvis - origin, insertion and structure

Answer 55

• extends from the medial end of the inguinal ligament backwards to the pectineal line and to the pubic tubercle
• its crescentic free edge forms the medial border of the femoral canal
  After attaching at the pubic tubercle its fibres may be traced upwards and medial, behind the spermatic cord where it interdigitates with the linea alba

Question 56

intercrural fibres of the inguinal ligament- origins and insertions

Answer 56

are at the apex of the superficial inguinal ring, where the crus of the external oblique separate and run at right angles to the aponeurosis and prevent the crura from separating
- are shiny and serve as a landmark intraop

Question 57

The superficial inguinal ring - structure

Answer 57

Above and lateral to the pubic tubercle
- formed by a V shaped opening in the external oblique
o lateral crus attached to the pubic tubercle
o medial crus attaches to the medial part of the pubic crest
o between no attachment form external oblique
o Gap extends down to the pubic crest
o medial to the pubic tubercle – the aponeurosis is attached to the pubic crest, only on its medial part alongside the pubic symphysis
o intercrural fibres run at right angles to the crus at the junction of the medial and lateral crus – shiny and serve as a landmark intra op
o the spermatic cord overlies the pubic tubercle—to palpate should invaginate the scrotum from behind the cord

Question 58

Internal oblique: origins, insertions, borders and course

Answer 58

•origin: triangle shape–> whole length of lumbar fascia, anterior 2/3rd of the iliac crest and the lateral 2/3 of the inguinal ligament from the rolled in lower border of the external oblique aponeurosis
o from the lumbar fascia they run upwards along the costal margin, to which they are attached becoming an aponeurosis at the 9th costal cartilage
• course: its aponeurosis splits around the rectus muscle and re-joins at the linea alba
• below the arcuate line the aponeurosis is attached to the pubic crest and pectineal line
• lower border is free and is muscular laterally and in front of the spermatic cord and tendinous medially and behind the cord

Question 59

the arcuate line of the abdominal wall

Answer 59

• the arcuate line (semicircular line of Douglas): is located 2.5cm below the umbilicus- at this point the aponeurosis passes anterior to the rectus muscle

Question 60

the cojoint tendon of the abdominal wall

Answer 60

•the conjoint tendon: attaches internal oblique at the pectineal line and pubic tubercle and fuses with the fibres of the transversis aponeurosis

Question 61

transversus abdominus origins and insertions

Answer 61

• origin: in continuity from the whole costal margin, lumbar fascia iliac crest and inguinal ligament
o from costal margin – fleshy slips arise from inside each costal cartilage, interdigitating with the costal margins of the diaphragm
o lumbar fascia is lateral to the quadratus lumborum, then from the internal lip of the iliac crest at the anterior 2/3rds and travelling over the fascia over the iliacus and lateral half of the inguinal ligament
• insertions – aponeurosis at linea alba behind the internal oblique aponeurosis, does not split like the internal oblique
o below arcuate line: aponeurosis passes Infront of rectus, above passes behind
o fuses with the internal oblique at the conjoint tendon on the pubic crest and along the pectineal line behind the spermatic cord

Question 62

rectus abdominus origins, insertions

Answer 62

•origins: 2 heads run superiorly
o medial – infront of the pubic symphysis
o lateral- from the upper border of the pubic crest
o at base they lie edge to edge but become separated by the linea alba above the umbilicus as the linea alba broadens
•insertion: 2 layers
o external oblique layer: 5-7th costal cartilages
o internal oblique layer: the lower border of the 7th costal cartilage (ie costal margin)
o transversus layer: at the xiphisternum
• three tendinous intersections exist – one at the umbilicus, one a the xiphisternum and one half way between
o fibres at the tendinous intersections blend with the anterior rectus sheath inseperably, they do not penetrate the muscle posteriorly
•the aponeurosis of the two recti fuse medially to form the linea alba – attached at the xiphoid process superiorly and pubic symphysis inferiorly

Question 63

pyramidalis

Answer 63

• origin: pubic crest between the rectus abdominus and its sheath
• insertion: travels 4cm superiorly before it joins its counterpart and converges in the linea alba

Question 64

structure of the rectus sheath - above and below costal margin and above and below arcuate line

Answer 64

• above the costal margin only the external oblique encloses anteriorly to the rectus
• below the costal margin and above the arcuate line: the internal oblique splits in two to enclose the rectus muscle
o external oblique fuses with internal anteriorly and the internal oblique and transversus abdominus fuse posteriorly above the arcuate line
o the arcuate line is the free ends of the above arrangement
• below the arcuate line all layers pass anteriorly to the rectus muscle

Question 65

semilunar line of internal oblique

Answer 65

• splitting of the internal oblique give rise to the semilunar line
o this curves up from the pubic tubercle to the costal margin at the tip of the 9th costal cartilage in the transpyloric plane

Question 66

contents of the rectus sheath

Answer 66

oposterior intercostal nerves (T7-T11): lie between the internal oblique and transversus abdominus, where they run in this plane to pierce the sheath by the posterior layer of the internal oblique
 in the sheath they travel behind the rectus muscle to the midline, where they pierce the recuts and the sheath to become the anterior cutaneous nerves
 before the sheath the nerves give off lateral cutaneous nerves which pierce the internal and external obliques to reach the skin, lateral cutaneous nerves also supply the external oblique
osuperior epigastric artery – terminal branch of internal thoracic
 enters the sheath by passing between the sternal and high costal fibres
 anastomoses with inferior epigastric
oinferior epigastric - leaves the external iliac at the inguinal ligament and passes upwards behind the conjoint tendon and slips over the semicircular fold and enters the sheath

Question 67

blood supply of the abdominal wall

Answer 67

• superior and inferior epigastric
• lumbar arteries
• deep circumflex iliac: arises from external iliac behind the inguinal ligament
o its runs laterally towards the anterior superior iliac sine in a canal of tissue formed by the meeting of the transversalis and iliac fascia meeting
 at the anterior superior iliac spine  gives off a branch which enters the neurovascular plane to anastomose with the inferior epigastric and lumbar arteries
• this branch is at risk in a gridiron incision
o it continues along the inner lip of the iliac crest and pierces the transversalis muscle
o form here it anastomoses with the iliolumbar and superior gluteal arteries

Question 68

nerve supply of abdominal wall

Answer 68

• rectus and external oblique: lower intercostal and subcostal nerves (T7-T11)
• internal oblique and transversalis – same nerves but addition of the iliohypogastric and ilioinguinal nerves

Question 69

actions of abdominal muscles

Answer 69

• move trunk: flexion, abductors and rotators of vertebral column
• depress ribs: recti + oblqiues – expiratory force in cough
o abdominal compression added with the use of transversalis  increased expiratory effort
• compressing abdomen- obliques + transversalie- forced expiration
o when diaphragms contracts and levator ani relaxes – excrete faeces
• supporting and protecting viscera

Question 70

structure of the inguinal canal: MALT

Answer 70

• roof (M):: Muscles- internal oblique and transversus abdominus
• anterior wall (A): aponeurosis - external oblique and internal oblique
• lower wall (L): inguinal ligament and lacunar ligament
• posterior wall (T): transversalis fascia and conjoint tendon

Question 71

location of the deep inguinal ring

Answer 71

The deep inguinal ring lies above the midpoint of the inguinal ligament

Question 72

What is the reflected part of the inguinal ligament

Answer 72

• the reflected part of the inguinal ligament is formed by fibres from the lateral crus at their attachment at the pubic tubercle which pass upwards behind the spermatic cord and behind the medial crus and blend with the rectus sheath on the opposite side
o they form an additional attachment of the ring- the posterior crus of the opposite aponeurosis of the external oblique

Question 73

The importance of the iliohypogastric and ilioinguinal nerves at the inguinal canal

Answer 73

• The lowermost fibres of the internal oblique and transervsus are supplied by the ioliohypogastric and ilioinguinal nerves (L1)
o Contraction tightens the conjoint tendon pulling the roof of the canal down
o Division of the ilioinguinal nerve (split muscle incision for appendectomy) will lead to direct inguinal hernia as the conjoint tendon buldges out with increased intrabadominal pressure
o Damage to the ilioinguinal nerve as it enters the canal does not cause this part is purely sensory

Question 74

The inguinal triangle (of Hesselbach)

Answer 74

• Medial border is rectus muscle, the lateral border is the inferior epigastric artery and below by the inguinal ligament
o Hernial sac passing lateral to the artery is an indirect hernia – and passes through the ring
o Direct hernia passes medial to the artery – and stretches the conjoint tendon over itself
• A femoral hernia – enters the femoral canal through the femoral ring, below the inguinal ligament and lateral to the lacunar ligament

Question 75

contents of the spermatic cord

Answer 75

• Three covering are picked up as it travels through the canal
1. Transversalis -> internal spermatic fascia at the entry to the deep inguinal ring
2. Internal oblique and Transversalis -> cremasteric fascia and cremasteric muscle in the canal
3. external oblique -> external spermatic fascial-> from the crura of the superficial inguinal ring
• constituents of the cord
1. ductus deferens – lies in the posterior part of the cord
2. arteries x3- testicular artery, artery to ductus deferens (from superior or inferior vesicle) and cremasteric artery (off inferior epigastric)
3. veins- pampiniform plexus
4. lymphatics – to para-aortic nodes from testes
5. nerves- genital branch of the genitofemoral nerve- supplies the cremaster muscle and the Sympathetic nerves
6. processus vaginalis- connection with the tunica vaginalsi of the test
 when patent causes indirect inguinal hernia

Question 76

structure of the roof of the inguinal canal - internal oblique and transversus abdominus

Answer 76

• Formed by the arched borders of the internal oblique and transversus abdominus muscles
- both muscles arise from the inrolled edge of the inguinal ligament
- from the lateral 2/3 of the inguinal ligament the fibres of the inguinal ligament arch medially and down to form an aponeurosis, teh lateral fibres just below the anterior superior iliac spine still pass along normally in front of the pubic syphysis
- Others however still pass in front of the rectus abdominus and pass along the pubic crest and as far as the pubic tubercle and extend laterally along the pectineal line as far as the crescentic edge of the lacunar ligament to form the cojoint tendon
- • The transversus abdominus – arises from the lateral half of the inguinal ligament deep to the internal oblique
o Fuse with internal oblique at the conjoint tendon

Question 77

the lacunar ligament and the floor of the inguinal canal

Answer 77

• The lacunar ligament connecting the inguinal ligament to the pectineal line forms the floor
• At the lacunar ligaments attachment to the inguinal ligament – it forms a gutter from which the transversalis fascia is fused with the inguinal ligament

Question 78

cojoint tendon of the inguinal region

Answer 78

The conjoint tendon (previously known as the inguinal aponeurotic falx) is a structure formed from the lower part of the common aponeurosis of the internal oblique muscle and the transversus abdominis as it inserts into the crest of the pubis and pectineal line immediately behind the superficial inguinal ring.

Question 79

structure of the posterior wall of the inguinal canal

Answer 79

• Medially the posterior wall consists of the conjoint tendon
• Lateral to this the wall is weak – only covered by areolar tissue of the transversalis fascia and peritoneum between the roof (internal oblique and transversus) and the floor (inguinal ligament)
• Strength of canal= integrity of the anterior wall in lateral part and posterior wall in medial part = tone of the abdominal muscles

Question 80

interfoveolar ligament of the posterior wall of the inguinal canal

Answer 80

• Interfoveolar ligament: travels down from the lower border of the transversalis, around the vas and attaches to the to the inguinal ligament
o Extends for a variable length along the inguinal ligament
o Forms the functional medial edge of the deep inguinal ring

Question 81

structure of the deep inguinal ring

Answer 81

• Deep inguinal ring lies above the midpoint of the inguinal ligament
o Is an opening in the transversalis fascia bounded laterally between the transversus muscle fibres and the inguinal ligament
o Medial border: is the transversalis fascia which is projected along the canal, and projects along the canal as the internal spermatic fascia
 Medial thickening of the fascia forms the interfoveolar ligament
o Spermatic cord passes through the ring

Question 82

ilioinguinal nerve

Answer 82

• The ilioinguinal nerve penetrates the anterior wall of the canal through penetrating external oblique aponeurosis and internal oblique muscle
o It exits through the superficial ring and forms skin supply to the inguinal region, upper part of the thigh and anterior third of scrotum

Question 83

Inferior epigastric artery course and associated structure

Answer 83

• The inferior epigastric artery crosses the deep inguinal ring at its medial edge
o Lateral to the artery the ductus deferens/ round ligament enter the canal by hooking around the interfoveolar ligament
• Is a branch of the external iliac – given off just before the inguinal ligament
• Penetrates the transversalis facia and runs over the arcuate line to penetrate the rectus sheath behind the rectus muscle
• Cremasteric branch of the inferior epigastric – enters the deep rings and supplies the cremaster
• Gives off a a pubic branch to the periosteum of the superior pubic ramus  this anastomoses with the obturator artery
The medial umbilical ligament passes obliquely across the posterior wall of the inguinal canal, medial to the inferior epigastric

Question 84

structure of the testes

Answer 84

• the seminiferous tubules are seperated into locules by the interlobular sept which radiate out from the mediastinum testes towards the tunica albuginae
• the seminiferous tubules open to the rete testes at the mediastinum
• from the rete testes, vasa efferentia 15-20 in number attach to the canal of the epididymis
• epididymis is attached to the posterolateral surface, from which the vas deferens continues from and passes medial to
• right and left sides are separated by the median scrotal septum

Question 85

what are the appendix tetis

Answer 85

appendix tetis: sessile cysts 2-3mm attached to the upper pole of the tests within the tunic vaginalis- is a remnant of the paramesonephric duct

Question 86

arterial and venous supply to the testes

Answer 86

• testicular artery – off the aorta
o course: off aorta-> runs in spermatic cord, gives branch to epididymis and reaches the back of the testses before dividing into the lateral and medial branches
o branches do not penetrate the mediastinum tetses but sweep around horizontally within the tunica albuginea
• veins drain to mediastinum and pass around the testicular artery forming the pampiniform plexus
o provides counter current heat exchange
o in the inguinal canal – the plexus can be separated into 4 veins which joint into one on the psoas major of the posterior wall
o left testicular vein drains into the left renal vein
o the right testicular vein drains into the inferior vena cava, but can drain into the right renal (more often than textbooks suggest)
o varicoceles occur more commonly on left
• in the region of the epididymis – there is an area of anastomosis between testicular, cremasteric and ductal arteries
o if dividing the main artery – atrophy will occur but necrosis is unlikely as other arteries can provide some supply

Question 87

lymph drainage of the testes

Answer 87

• lymphatic capilleries lie between and not within the seminiferous tubules
• lymphatic run with testicular artery to para aortic nodes – entering at L2
• overlying scrotal skin drains to inguinal nodes

Question 88

nerve supply to the testes

Answer 88

• T10 sympathetic nerves  Nerves pass in the greater or leser splanchnic nerve to coeliac ganglion and synapse there  Post ganglionic reach test along testicular artery
• No parasympathetic supply
• Sensation: share same pathway as sympathetic coeliac plexus  lesser splanchnic nerve white ramus DRG of T10

Question 89

spermatogenesis and supporting cells

Answer 89

• Outer layer of each seminiferous tubule is spermatogonia (germ cell)-> divide by mitosis-> primary spermatocytes (next 2 layers)-> meiosis -> secondary spermatocytes -> divide again spermatids -> metamorphosis -> spermatozoa
• Sustentacular cells (of Sertoli) produce androgen binding protein
o Form a network amongst themselves which germ cells are embedded
• Interstitial cells (of Leydig): produce testosterone

Question 90

process of the descent of the testes

Answer 90

• The testes themselves are derived from the gonadal ridge, medial to the mesonephric ridge of the intermediate cell mass
• By the final month of foetal life- the testes lies near the deep inguinal ring, connected to the anterior abdominal wall by a peritoneal fold
• During the 7th month it progressed through the inguinal canal over a few weeks – this is the descent of the testes
• The processus vaginalis, an elongated diverticulum of the peritoneal cavity precedes the testes into the scrotum, with the testes moving down behind it
• The processus vaginalis obliterates except at the lower end where it forms the tunic vaginalis
o It forms the parietal layer and blends with the visceral layer which is testicular in origin
• The Gubernaculum is a mesodermal condensation of the lower end of the gonad which swells by imbibition of water to enlarge the passage for descent  it proceeds the testes
o Aberrant strands are associated with ectopic testes
• Hydrocele of the cord is caused by failure of the processus to obliterate at parts of the cord
• Indirect inguinal hernia is caused by failure of the processus to obliterate at all

Question 91

histology of the epididimus and vas

Answer 91

• Epididimus: tube – inner is lined by tall columnar epithelium with stereocilia (not true cilia- but long non motile microvilli). Outer wall is fibrous tissue
• Vas deferens: thick 3 layer smooth muscle wall: inner and outer longitudinal, middle circular. Inner mucosa- thin basal layer of dense fibrous tissue with callumnar epithelium with stereocilia

Question 92

embryology of the epididimus and vas

Answer 92

• Formed from the mesonephric duct (Wolffian duct)
• The mesonephric duct is connected to the mesonephros by the mesonephric tubules
• When the mesonephros becomes the metanephros and disappears, the mesonephric tubules either become attached to the testes forming the vasa efferentia or they form blind ends at one or both ends
o Blind at one end and connected to the forming epididimus are called Vas aberrans
 The Vas aberrans superior is common and forms the appendix of the epididimus
 Others form small swelling son the epididimus
o Blind tubules at both ends  a mass of these located superiorly forms the paraepididimus (aka organ of Giraldes)
• The paramesonephric duct (Mullerian) disappears in men, buts its two ends may persist as the appendix testes and prostatic utricle (utriculus masculinus)

Question 93

the transpyeloric plane

Answer 93

bisects the body midway between the jugular notch and pubic symphysis
o Cuts the costal margins at tip of 9th costal cartiledge, which is at the lateral border of the rectus abdominus (semilunar line)
o Beneath on the left is the fundus of the gall bladder and on the right the body of the stomach
o Passes trhough the 1st lumbar vertebrae  conus medularis and the pylorus of the stomach
o Also passes through the head of the pancreas behing the pylorus of the somach as well as the neck and body, just above the attachment of the transverse mesocolon
o SMA leaves the aorta at this plane and splenic vein behind the pancreas
o Hilum of each kidney is in this plane
o Above lies the liver, spleen and fundus of the stomach (supracolic compartment) and below lies the small intestine and stomach (infracolic compartment)

Question 94

peritoneal folds of the anterior abdominal wall

Answer 94

• On the posterior surface of the abdominal wall – the peritoneum is raised into 6 folds- 5 below umbilicus and 1 above
• Above 1) The falciform ligament: contains the ligamentum teres at its base (obliterated remains of the umbilical vein) and left umbilical vein –> round ligament of the liver and tehir associated paraumbilcal veins. Passes upwards from the midline and deviates rightwards and enters its named fissure on the liver on its visceral surface and continues upwards on the anterior and superior surface of the liver before separating
• Below: 1) Median umbilical fold. Contains the median umbilical ligamnts (remains of the urachus)
o 2+3) medial umbilical fold. Contains medial umbilical ligaments (obliterated remains of umbilical artery) – one on each side
o Above three inserts at umbilicus
o 4+5) lateral umbilical fold. Contains inferior epigastric vessels which enter the rectus sheath passing beneath the arcuate line

Question 95

boundaries of the lesser sac

Answer 95

• Lesser sac (Omental bursa): space behind the stomach, created by the peritoneum of liver, stomach and spleen
o Opens to the greater sac by the epiploic foramen, in front of the IVC
o Anterior wall: stomach and lesser omentum and gastrocolic omentum
 Left it extends to the hilum of the spleen – to form the lienorenal ligament and the gastrosplenic
o Roof: sloping roof of peritoneum that covers the caudate lobe of the liver
o Inferior wall wall is transverse mesocolon, attached to the lowest part of the pancreas
 Incision of either of the above leads to greater ability to explore the lesser sac due to the space bound posteriorly by the pancreatico gastric and duodenal folds
o Posterior wall is parietal peritoneum

Question 96

attachments of the greater omentum

Answer 96

• greater curvature of the stomach - continuous from abdominal oesophagus to duodenum - the 4 layers fuse and hang off the greater curvature
• connects the stomach to the spleen by the gastrosplenic ligament and spleen and kidney via the lienorenal ligament
• Above the spleen the greater omentum passes from the back of the stomach to the diaphragm above the kidney as the gastrophrenic ligament
• The greater omentum immediately below the stomach fuses with the transverse mesocolon – forming the gastrocolic omentum