Abdomen Flashcards
(181 cards)
1
Q
What are the left and right crus of the diaphragm?
A
A muscular extension on each side of the vertebral column that firmly anchors the diaphragm to the anterolateral surface of the vertebral column as far down as L3 on the right and L2 on the left.
2
Q
What are the medial and lateral arcuate ligaments?
A
Because the diaphragm is not complete posteriorly, the diaphragm is anchored to ligaments. The medial and lateral arcuate ligaments cross muscles of the posterior abdominal wall and attach to vertebrae, the transverse process of L1 and rib 12, respectively.
3
Q
Where is the median arcuate ligament located?
A
It crosses the aorta and is continuous with the crus of the diaphragm on each side
4
Q
Which nerves supply cutaneous innervation to the abdominal wall?
A
T6-L1
5
Q
Which nerve root supplies the skin over the xiphoid process?
A
T6
6
Q
Which nerve root supplies the skin around the umbilicus?
A
T10
7
Q
Which nerve root supplies the skin in the suprapubic and inguinal regions?
A
L1
8
Q
At what level does the celiac artery branch from the abdominal aorta?
A
upper border of L1
9
Q
At what level does the superior mesenteric artery branch from the abdominal aorta?
A
lower border of L1
10
Q
At what level does the inferior mesenteric artery branch from the abdominal aorta?
A
L3
11
Q
Where does sympathetic innervation to abdominal viscera originate from?
A
Spinal cord levels T5 to L2
12
Q
Where does parasympathetic innervation to abdominal viscera originate from?
A
Vagus nerve and spinal cord levels S2 to S4
13
Q
What are the lines that delineate the the 9 regions of the abdomen?
A
Horizontal - subcostal (or transpyloric) and intertubercular
Vertical - two midclavicular lines
14
Q
What are the 9 regions of the abdomen from right to left, superiorly to inferiorly?
A
Right hypochondrium, Epigastric region, Left hypochondrium
Right flank, Umbilical region, Left flank
Right groin (iliac fossa), Pubic region, Left groin
15
Q
What are the two layers of superficial fascia in the anterior abdominal wall, below the umbilicus?
A
- Superficial fatty layer (Camper’s fascia) contains fat and varies in thickness
- Deeper membranous layer of fascia (Scarpa’s fascia) is thin and membranous, and contains little or no fat
16
Q
What is Camper’s fascia continuous with in the scrotum?
A
Dartos fascia, a specialised layer containing smooth muscle fibres. In women, it retains some fat and is a component of the labia majora.
17
Q
What are the five anterolateral muscles of the abdominal wall?
A
External oblique, internal oblique, transversus abdominis, rectus abdominis and pyramidalis muscles
18
Q
Where is the lacunar ligament located?
A
Medial end of the inguinal ligament that passes backward to attach to the pecten pubis on the superior ramus of the pubic bone
19
Q
Where is the transversalis fascia located?
A
Deep to the transversus abdominis muscle, it is a continuous layer that lines the abdominal cavity and continues in to the pelvic cavity
20
Q
What is the origin of the external oblique muscle?
A
Muscular slips from the outer surfaces of the lower 8 ribs (ribs 5-12)
21
Q
What is the insertion of the external oblique muscle?
A
Lateral lip of iliac crest and the aponeurosis ending in the linea alba
22
Q
What is the function of the external oblique muscle?
A
Compress abdominal contents, flex the trunk, each muscle bends trunk to the same side, turning the anterior part of the abdomen to the opposite side
23
Q
What is the origin of the internal oblique muscle?
A
Thoracolumbar fascia, iliac crest, lateral two-thirds of the inguinal ligament
24
Q
What is the insertion of the internal oblique muscle?
A
Inferior border of the lower 3/4 ribs, aponeurosis endind in the linea alba, pubic crest and pectineal line
25
What is the origin of the rectus abdominis muscle?
Pubic crest, pubic tubercle and pubic symphysis
26
What is the insertion of the rectus abdominis muscle?
Costal cartilages of ribs 5-7 and the xiphoid process
27
What is the function of the rectus abdominis muscle?
Compress abdominal contents, flex vertebral column and tense abdominal wall
28
What is the origin of the transversus abdominis muscle?
Thoracolumbar fascia, iliac crest, lateral one-third of inguinal ligament, costal cartilages of lower 6 ribs
29
What is the insertion of the transversus abdominis muscle?
Aponeurosis ending in the linea alba, pubic crest and pectineal line
30
What is the function of transversus abdominis?
Compress the abdominal contents
31
What is the origin of the pyramidalis muscle?
Front of pubis and pubic symphysis
32
What is the insertion of the pyramidalis muscle?
Into the linea alba
33
What is the function of the pyramidalis muscle?
Tenses the linea alba
34
What is the innervation of the three flat abdominal muscles?
Anterior rami of lower six thoracic spinal nerves (T7-T12), Internal oblique and transversus abdominis also innervated by L1
35
What is the innervation of rectus abdominis?
Anterior rami of lower six thoracic spinal nerves (T7-T12)
36
What is the innervation of the pyramidalis muscle?
Anterior ramus of T12
37
Above the arcuate line, what does the anterior wall of the rectus sheath consist of?
The aponeurosis of external oblique
| Half of the aponeurosis of internal oblique
38
Above the arcuate line, what does the posterior wall of the rectus sheath consist of?
(Other) Half of the aponeurosis of internal oblique
| The aponeurosis of transversus abdominis
39
Below the arcuate line, what is the arrangement of the rectus sheath?
All of the aponeuroses are anterior to the rectus abdominis muscle, meaning the rectus abdominis is in direct contact with transversalis fascia posteriorly (at it's inferior 1/3rd)
40
Describe the extraperitoneal fascia
It is deep to the transversalis fascia and superficial to the peritoneum. It contains varying amounts of fat, is continuous with a similar layer in the pelvic cavity and is abundant on the posterior wall, especially around the kidneys. It also continues over organs covered by peritoneal reflections,
41
The peritoneal cavity is closed in men but not in women, what are the two openings in women?
The uterine tubes provide a passage to the outside
42
What are the specific nerves which supply cutaneous innervation to the abdominal wall?
```
Intercostal nerves (T7-T11) - their lateral and anterior cutaneous branches
Subcostal nerve (T12)
Iliohypogastric and Ilioinguinal nerves (branches of L1, originate from the lumbar plexus)
```
43
Briefly describe the course of the anterior cutaneous branches of the lower intercostal nerves
Anterior cutaneous branch is given off as the intercostal nerve travels between the internal oblique muscle and the transversus abdominis muscle towards the rectus sheath. It enters the rectus sheath, passes posteriorly to the rectus abdominis muscle and near the midline the anterior cutaneous branch is given off. This branch passes through the rectus abdominis muscle and rectus sheath to supply the skin.
44
What is the superficial blood supply of the anterolateral abdominal wall?
Superiorly - Musculophrenic artery (a terminal branch of the internal thoracic)
Inferiorly - medially; the superficial epigastric artery
- laterally; the superficial circumflex iliac artery
(Both branches which supply the inferior superficial abdominal wall are branches of the femoral artery)
45
What is the deep blood supply to the anterolateral abdominal wall?
Superiorly - Superior epigastric artery (a terminal branch of the internal thoracic artery)
Laterally - Branches of the 10th and 11th intercostal arteries and the subcostal artery
Inferiorly - the medially place inferior epigastric artery and the laterally placed deep circumflex iliac artery. Both branches of the external iliac artery.
46
Very briefly describe the course of the inferior and superior epigastric arteries?
They both enter the rectus sheath, are posterior to the rectus abdominis muscle and anastamose with eachother
47
What are the tendinous intersections of the rectus abdominis muscle?
They are between the muscle bellies and it is where the muscle is attached to the rectus sheath.
48
How is the peritoneal cavity subdivided?
The greater sac and the lesser sac
49
What is the communication between the greater and lesser sac?
The omental (epiploic foramen), which is surrounded by numerous structures. Anteriorly, the portal vein, hepatic artery proper and bile duct. The IVC posteriorly and the caudate lobe of the liver superiorly. The first part of the duodenum inferiorly.
50
What is the arterial supply to the abdominal oesophagus?
Oesophageal branches from the left gastric artery (a branch of the coeliac trunk)
Oesophageal branches from the left inferior phrenic artery (from the abdominal aorta)
51
What are the four regions of the stomach?
Cardia - surrounding the opening of the oesophagus into the stomach
Fundus - area above the level of the cardial orifice
Body - largest region
Pyloric part - divided in to the pyloric antrum and the pyloric canal and is the distal end of the stomach
52
What is the greater curvature of the stomach an attachment for?
The gastrosplenic ligament and the greater omentum
53
What is the lesser curvature of the stomach an attachment for?
The lesser omentum
54
Where is the cardial notch?
The superior angle created where the oesophagus enters enters the stomach
55
What is the angular incisure?
The bend on the lesser curvature of the stomach
56
What is the arterial supply to the stomach?
Left gastric artery from the celiac trunk
Right gastric artery from the hepatic artery proper
Right gastroepiploic artery from the gastroduodenal artery
Left gastroepiploic from the splenic artery
Posterior gastric artery from the splenic artery (not always present)
57
What does the superior part (first part) of the duodenum pass anteriorly to?
It extends from the pyloric orifice of the stomach to the neck of the gallbladder. It passes infront of the bile duct, gastroduodenal artery, portal vein and inferior vena cava
58
Where are duodenal ulcers most likely to occur?
The first part of the duodenum, due to its close proximity to the acidic contents of the stomach before it is neutralised by bile
59
What structures are associated with the descending part (second part) of the duodenum?
Crossed anteriorly by the transverse colon, posterior to it is the right kidney and medial to it is the head of the pancreas.
It also contains the major and minor duodenal papilla
60
What are the major and minor duodenal papilla?
The major duodenal papilla is the common entrance of bile and pancreatic ducts
The minor duodenal papilla is the entrance for the accessory pancreatic duct
61
What structures are associated with the inferior part (3rd part) of the duodenum?
It is the longest part. It crossed the IVC, the aorta, and the vertebral column. It is crossed anteriorly by the superior mesenteric artery and vein
62
What structures are associated with the ascending part (4th part) of the duodenum?
It passes upward on, or to the left of, the aorta to approximately the upper border of L2 and terminates at the duodenojejunal flexure.
63
What is the duodenojejunal flexure surrounded by?
A fold of peritoneum containing muscle fibres called the suspensory muscle (ligament) of duodenum
64
What is the arterial supply to the duodenum?
Branches from the gastroduodenal artery
Supraduodenal artery (a branch of the gastroduodenal artery)
Duodenal branches from the anterior superior, anterior inferior, posterior superior and posterior inferior pancreaticoduodenal arteries
The first jejunal branch of the SMA
65
Where do the pancreaticoduodenal arteries arise from?
Anterior superior and Posterior superior arise from the gastroduodenal artery
Anterior inferior and Posterior inferior arise from the inferior pancreaticoduodenal artery which is a branch of the SMA
66
What are the characteristic features of the jejunum?
Mostly in the left upper quadrant, is larger in diameter and has a thicker wall than the ileum.
Numerous plicae circulares
Less prominent arterial arcades and longer vasa recta compared to those of the ileum
67
What is the blood supply to the jejunum?
Jejunal arteries from the SMA
68
What are the characteristic features of the ileum?
Mostly in the right lower quadrant. Compared to the jejunum, it has thinner walls, fewer and less prominent plicae circularis, shorter vasa recta, more mesenteric fat, and more arterial arcades.
69
What lies at the junction between the ileum and caecum?
Two flaps protude in to the lumen of the large intestine, the ileocecal fold, surrounding the opening. Musculature from the ileum continues in to each flap forming a sphincter.
70
What are the possible functions of the ileocecal fold?
Preventing reflux from the cecum to the ileum and regulating passage of contents from the ileum to the cecum.
71
What is the arterial supply to the ileum?
Ileal arteries from the SMA
| An ileal branch from the ileocolic artery (from the SMA)
72
What are the four general features of the large intestine?
Large internal diameter compared to that of the small intestine
Peritoneal accumulations of fat - appendices epiploicae
Longitudinal muscles in its wall in three narrow bands - taeniae coli
The haustra of the colon (sacculations)
73
What are you most likely to see the taeniae coli?
Primarily observed in the cecum and colon and less visible in the rectum
74
Describe the appendix
It is a narrow, hollow, blind ended tube connected to the posteromedial wall of the cecum, just inferior to the end of the ileum. It has large aggregations of lymphoid tissue in its walls and is suspended from the terminal ileum by the mesoappendix, which contains the appendicular vessels. Its point of attachment to the cecum is consistent with the highly visible free taenia leading directly to the base of the appendix, but the location of the rest of the appendix varies considerably.
75
What is the arterial supply to the cecum and appendix?
anterior cecal artery, posterior cecal artery and the appendicular artery which are all branches of the iliocolic artery which is a branch of the SMA
76
Which parts of the colon on retroperitoneal and intraperitoneal?
The ascending and descending colon are secondarily retroperitoneal and the cecum, transverse and sigmoid colon are intraperitoneal
77
When performing a colonoscopy, which bend might be particularly difficult to navigate?
The left colic flexure (splenic flexure) as it is a more acute bend than the right colic flexure (hepatic flexure)
78
What is immediately lateral to the ascending and descending colon?
The right and left paracolic gutters. Because major vessels and lymphatics are on the medial and posteromedial sides of the ascending and descending colon, a relatively blood-free mobilisation of the ascending and descending colon is possible by cutting the peritoneum along these lateral paracolic gutters.
79
What are the branches of the SMA that supply the colon, and which parts of the colon do they supply?
Iliocolic, right colic and middle colic arteries. They supply the cecum, appendix, ascending colon and 2/3rds along the transverse colon i.e. the parts of the colon that are classed as the midgut (SMA supplies midgut)
80
What are the branches of the IMA that supply the colon, and which parts of the colon do they supply?
left colic artery supplies the descending colon which also anastamoses with the middle colic artery. The sigmoid colon is supplied by sigmoidal arteries (from the IMA)
81
What vertebra level is the rectosigmoid junction at?
S3
82
What is the arterial supply to the rectum and anal canal?
The superior rectal artery (from the IMA)
The middle rectal artery (from the internal iliac artery)
The inferior rectal artery (from the internal pudendal artery which is from the internal iliac artery)
83
What are the three muscle layers in the stomach?
Longitudinal, circular and oblique (from superficial to deep)
84
What are the boundaries of the bare area on the liver?
Anterior boundary is the anterior coronary ligament, posterior boundary is the posterior coronary ligament. The lateral boundaries are formed by the left and right triangular ligaments which are formed from the two coronary ligaments coming together laterally.
85
What are the boundaries of the quadrate lobe?
It is bounded on the left by the fissure for ligamentum teres and on the right by the fossa for the gallbladder
86
What are the boundaries of the caudate lobe?
It is bounded on the left by the fissure for the ligamentum venosum and on the right by the groove for the IVC
87
Which lobes (right or left) are the quadrate and caudate lobes functionally related to?
Quadrate lobe is functionally related to the left lobe of the liver
Caudate lobe is functionally separate from the right and left lobes of the liver
88
What is the arterial supply to the liver?
Right and left hepatic arteries which are branches of the common hepatic artery which is a branch of the coeliac trunk
89
What attaches the liver to the anterior abdominal wall?
The falciform ligament
90
Briefly describe the structure of the gallbladder
It has a rounded end, the fundus of the gallbladder, which may project from the inferior border of the liver
A major part is in the fossa, the body of the gallbladder, which may be against the transverse colon and the superior part of the duodenum
A narrow part, the neck of the gallbladder, with mucosal folds forming the spiral fold
91
What is the arterial supply to the gallbladder?
The cystic artery which is a branch of the right hepatic artery
92
What is the ligamentum venosum a remnant of and where is it located?
A remnant of the ductus venosus which serves to shunt a portion of the blood flow in the left umbilical vein to the IVC
93
What does the mucosa of the gallbladdder resemble?
Honeycomb
94
What is the ligamentum teres a remnant of, and where is it located?
The umbilical vein, it is located at the free border of the falciform ligament
95
Which parts of the pancreas are retroperitoneal?
All of the pancreas is secondary retroperitoneal except for a small part of its tail
96
Briefly describe the anatomy of the pancreas
The head of the pancreas lies within the C-shaped concavity of the duodenum
Projecting from the lower part of the head is the uncinate process, which passes posterior to the SMA
The neck of the pancreas is anterior to the superior mesenteric vessels. Posterior to the neck of the pancreas the superior mesenteric and the splenic vein join to form the portal vein
The body of the pancreas is elongate and extends from the neck to the tail
The tail of the pancreas passes between layers of the splenorenal ligament
97
Where do the bile duct and pancreatic duct join and what is this part called?
They join in the lower part of the head of the pancreas and form the ampulla of Vater (hepatopancreatic ampulla)
98
What surrounds the ampulla of Vater?
The sphincter of Oddi
99
What is the arterial supply to the pancreas?
Gastroduodenal artery - from the common hepatic artery
Anterior superior and posterior superior pancreaticoduodenal artery from the gastroduodenal artery
Anterior inferior and posterior inferior pancreaticoduodenal from the inferior pancreaticoduodenal artery (from the SMA)
Dorsal and greater pancreatic artery from the inferior pancreatic artery (a branch of the splenic artery)
100
Describe the biliary tree
The coalescence of ducts begins in the liver parenchyma and continues until the left and right hepatic ducts are formed. These drain the respective lobes of the liver. The two hepatic ducts combine to form the common hepatic duct, which runs, near the liver, with the hepatic artery proper and portal vein in the free margin of the lesser omentum. As the common hepatic duct continues to descend, it is joined by the cystic duct from the gallbladder. This completes the formation of the bile duct. At this point the bile duct lies to the right of the hepatic artery proper and usually to the right of, and anterior to, the portal vein. The omental foramen is posterior to these structures at this point. The bile duct passes posterior to the superior part of the duodenum before joining the pancreatic duct to enter the descending part of the duodenum.
101
What is the surface anatomy of the spleen?
It lies against the diaphragm, in the area of rib 9 to rib 10. It also lies in the midaxillary line.
102
What are the two main categories of spleen disorders?
Rupture and enlargement
Localised trauma to the left upper quadrant and it is part of the reticuloendothelial system so any disorder affecting this may result in splenomegaly
103
What marks the junction between the foregut and the midgut?
Just inferior to the major duodenal papilla
104
What structures are part of the foregut?
Abdominal oesophagus, stomach, duodenum (proximal to just inferior to the major duodenal papilla), liver, gallbladder, pancreas and spleen.
105
What is the first branch of the SMA?
The inferior pancreaticoduodenal artery (on the right)
106
What are the left sided branches of the SMA?
Jejunal and Ileal branches
107
What are the right sided branches of the SMA?
inferior pancreaticoduodenal artery, middle colic, right colic and iliocolic arteries (from superior to inferior)
108
What is the terminal branch of the IMA?
Superior rectal artery
109
Where does the superior rectal artery divide?
Opposite vertebra S3 after crossing the left common iliac vessels.
110
What is the portal vein formed from and where does it form?
The union of the superior mesenteric vein and the splenic vein posterior to the neck of the pancreas at the level of L2
111
What are the tributaries to the portal vein?
Right and left gastric veins, cystic veins and para-umbilical veins (associated with the obliterated umbilical vein and connect to veins on the anterior abdominal wall)
112
What are the tributaries to the splenic vein?
Short gastric veins
Left gastro-omental vein
Pancreatic veins
Inferior mesenteric vein (usually)
113
Where do the two sympathetic trunks come together and what is this called?
Anterior to the coccyx, it is called the ganglion impar
114
Which muscles form the posterior abdominal wall?
Psoas major and minor, medially
Quadratus lumborum, laterally
Iliacus muscle, inferiorly
Diaphragm, superiorly
115
What is the origin of psoas major?
Lateral surfaces of bodies of T12 to L5 vertebrae
Transverse processes of the lumbar vertebrae
Intervertebral discs between T12 to L5 vertebrae
116
What is the insertion of psoas major?
Lesser trochanter of the femur
117
What is the innervation of psoas major?
Nerve to psoas major, anterior rami of L1-L3
118
What is the action of psoas major?
Flexion of the thigh at the hip joint
119
What is the function of quadratus lumborum?
Depress and stabilise rib 12 and some lateral bending of the vertebral column
120
What is the origin of iliacus?
Upper 2/3rds of the iliac fossa
Anterior sacroiliac and iliolumbar ligaments
Upper lateral surface of the sacrum
121
What is the insertion of iliacus?
Lesser trochanter of the femur
122
What is the innervation of iliacus?
Femoral nerve (L2-L4)
123
What is the function of iliacus?
Flexion of the thigh at the hip joint
124
What surrounds the kidneys and suprarenal glands?
Renal fascia which is a membranous condensation of extraperitoneal fascia which encloses the perinephric fat
The perinephric fat is immediately outside the renal capsule and completely surrounds the kidney.
125
What fat accumulates particularly posterior and posterolateral to each kidney?
Paranephric fat
126
Draw and label a diagram of the internal structure of the kidney
Renal capsule, renal cortex, renal pyramids, renal medulla, minor calyx, major calyx, renal sinus, renal pelvis, ureter, hilum of the kidney, renal column, renal papilla
127
Where is the origin of the left and right renal arteries?
Arise just inferior to the origin of the SMA between L1 and L2. The left renal artery usually arises a little higher than the right, and the right renal artery is longer and passes posterior to the IVC
128
Describe the renal veins and the significance of the left renal vein
Multiple renal veins contribute to the formation of the left and right renal veins, both of which are anterior to the renal arteries. The longer left renal vein crosses the midline anterior to the abdominal aorta and posterior to the SMA and can be compressed by an aneurysm in either of these two vessels
129
When the renal artery passes around a medullary pyramid, what is the name of these arteries?
Interlobar arteries and they loop over the pyramids as arcuate arteries
130
Briefly describe the course of a ureter
Renal pelvis narrows as it passes inferiorly through the hilum of the kidney and becomes continuous with the ureter at the ureteropelvic junction. Inferior to this junction, the ureters descend retroperitoneally on the medial aspect of the psoas major muscle. At the pelvic brim, the ureters cross either the end of the common iliac or the beginning of the external iliac arteries, enter the pelvic cavity and continue their journey to the bladder.
131
What are the three points of constriction along the course of the ureter?
Ureteropelvic junction
Where the ureters cross the common iliac vessels at the pelvic brim
Where the ureters enter the wall of the bladder
132
Describe the suprarenal arterial supply
It is extensive and arises from three primary sources:
- As the bilateral inferior phrenic arteries pass upward from the abdominal aorta to the diaphragm, they give off multiple branches (superior suprarenal arteries)
- A middle branch (middle suprarenal artery) arises directly from the abdominal aorta
- Inferior branches (inferior suprarenal arteries) from the renal arteries pass upward to the suprarenal glands
133
What is the difference between the venous drainage of the right and left suprarenal glands?
The right suprarenal gland has a single vein that leaves the hilum of the gland and is short and almost immediately enters the IVC
The left suprarenal gland has a single vein that leaves the hilum of the gland and passes inferiorly to enter the left renal vein
134
At what point does the abdominal aorta bifurcate?
Just to the left of the midline at the lower level of L4
135
How might you classify branches of the abdominal aorta?
Visceral branches supplying organs
Posterior branches supplying the diaphragm or body wall
Terminal branches
136
How might you subdivide the visceral branches of the abdominal aorta?
Either unpaired or paired vessels
137
What are the unpaired visceral branches of the abdominal aorta?
Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery
138
What are the paired visceral branches of the abdominal aorta?
Middle suprarenal arteries - small, lateral branches arising just above the renal arteries
Renal arteries - lateral branches that arise just inferior to the origin of the SMA between L1 and L2
Testicular and ovarian arteries - anterior branches of that arise below the origin of the renal arteries, and pass downward and laterally on the anterior surface of the psoas major
139
What are the posterior branches of the abdominal aorta?
Inferior phrenic arteries
Lumbar arteries
Median sacral artery
140
Briefly describe the inferior phrenic arteries
They arise immediately inferior to the aortic hiatus either directly from the abdominal aorta, as a common trunk from the AA or from the base of the celiac trunk. They pass upward, provide some arterial supply to the suprarenal glands (superior suprarenal artery), and continue on to the inferior surface of the diaphragm
141
Briefly describe the lumbar arteries
There are usually four pairs arising from the posterior surface of the AA. They demonstrate a branching pattern similar to a posterior intercostal artery, which includes providing segmental branches that supply the spinal cord
142
Briefly describe the median sacral artery
It is the final posterior branch of the abdominal aorta. It arises from the posterior surface just superior to the bifurcation and passes in an inferior direction, first over the anterior surface of the lower lumbar vertebrae and then over the anterior surface of the sacrum and coccyx
143
Where is the IVC formed and what is it formed from?
The two common iliac veins at the level of L5, just to the right of the midline
144
What are the tributaries to the IVC?
```
common iliac veins
lumbar veins
right testicular or ovarian vein
renal veins
right suprarenal vein
inferior phrenic veins
hepatic veins
```
145
Why are the lumbar veins unique in their connections?
The fifth lumbar vein generally drains in to the iliolumbar vein, a tributary of the common iliac vein
The 3rd and 4th lumbar veins usually drain into the IVC
The first and second lumbar veins may empty into the ascending lumbar veins
146
Briefly describe the ascending lumbar veins
They are long, anastomosing venous channels that connect the common iliac, iliolumbar, and lumbar veins with the azygous and hemiazygous veins of the thorax
147
What do gray ramus communicans contain?
Postganglionic sympathetic nerve fibres
148
What do white ramus communicans contain?
Myelinated and unmyelinated preganglionic sympathetic nerve fibres
149
Why do white ramus communicans appear white?
There are more myelinated than unmyelinated fibres (unlike gray ramus communicans)
150
What is the function of the white ramus communicans?
It is the preganglionic sympathetic outflow nerve tract from the spinal cord
151
At which spinal levels are the white ramus communicans found?
T1-L2, unlike the gray ramus communicans which are found at each spinal level
152
What is the referral area of pain for the heart and why?
The afferent pathway is the thoracic splanchnic nerves and the spinal cord level is T1-T4. Pain is felt in the upper thorax and medial arm
153
What is the pain referral pathway for the foregut and where is pain referred to?
Pathway is via the greater splanchnic nerve (T5 to T9 (or T10)) and pain is referred to the lower thorax and epigastric region
154
What is the pain referral pathway for the midgut and where is pain referred to?
Pathway is via the lesser splanchnic nerve (T9, T10 or T10, T11) and pain is referred to the umbilical region
155
What is the pain referral pathway for the hindgut and where is pain referred to?
Pathway is via the lumbar splanchnic nerves (L1, L2) and pain is referred to the left and right flanks and groins, lateral and anterior thighs
156
What is the pain referral pathway for the kidneys and upper ureter?
Pathway is via the least splanchnic nerve (T12) and pain is referred to the flanks and pubic region
157
What is the lumbar plexus formed from?
Anterior rami of nerves L1 to L3, and most of the anterior ramus of L4. It also receives a contribution from the T12 (subcostal) nerve
158
What are the branches of the lumbar plexus?
```
Iliohypogastric
Ilio-inguinal
Genitofemoral
Lateral cutaneous nerve of the thigh
Femoral
Obturator
```
159
How can the branches of the lumbar plexus be subdivided?
The lumbar plexus forms in the substance of the psoas major muscle. Therefore, relative to the psoas major muscle, the various branches are; anterior, medial and lateral
160
What are the anterior branches of the lumbar plexus?
Genitofemoral nerve
161
What are the medial branches of the lumbar plexus?
Obturator nerve
162
What are the lateral branches of the lumbar plexus?
Iliohypogastric, ilio-inguinal, femoral nerves and lateral cutaneous nerve of the thigh
163
What is the origin of the iliohypogastric and ilio-inguinal nerves?
Anterior ramus of L1
164
What is the motor supply of the iliohypogastric nerve?
Internal oblique and transversus abdominis
165
What is motor supply of the ilio-inguinal nerve?
Internal oblique and transversus abdominis
166
What is the sensory supply of the iliohypogastric nerve?
Posterolateral gluteal skin and skin in the pubic area
167
What is the sensory supply of the ilio-inguinal nerve?
Skin in the upper medial thigh, and either the skin over the root of the penis and anterior scrotum or the mons pubis and labium majus
168
What is the origin of the genitofemoral nerve?
Anterior rami of L1 and L2
169
What is the origin of the lateral cutaneous nerve of the thigh?
Anterior rami of L2 and L3
170
What is the motor function of the genitofemoral nerve?
Genital branch supplies the male cremasteric muscle
171
What is the sensory supply of the genitofemoral nerve?
Genital branch - skin of anterior scrotum or skin of mons pubis and labium majus
Femoral branch - skin of upper anterior thigh
172
What is the sensory supply of the lateral cutaneous nerve of the thigh?
Skin on anterior and lateral thigh to the knee
173
What is the origin of the obturator nerve and the femoral nerve?
Anterior rami of L2 to L4
174
What is the motor supply of the obturator nerve?
Obturator externus
Pectineus
Medial compartment of the thigh
175
What is the sensory supply of the obturator nerve?
Skin on medial aspect of thigh
176
What is the motor supply of the femoral nerve?
Iliacus
Pectineus
Anterior compartment of the thigh
177
What is the sensory supply of the femoral nerve?
Skin on anterior thigh and median surface of the leg (saphenous nerve)
178
What does the internal oblique muscle become in the spermatic cord?
Cremasteric fascia
179
What does the transversalis fascia become in the spermatic cord?
Internal spermatic fascia
180
What does the external oblique muscle become in the spermatic cord?
External spermatic fascia
181
What are the walls of the inguinal canal made up of?
MALT
External oblique muscle and transversus abdominis muscle
External oblique aponeurosis and internal oblique aponeurosis
Lacunar ligament and Inguinal ligament
Conjoint tendon and Transversalis fascia
