1. Posterior Abdominal Wall Diaphragm Lymphatics and Nerves
Dr. Paul Severson
Unit 21
Posterior Abdominal Wall Diaphragm Lymphatics and Nerves

2. The diaphragm is a dome-shaped musculotendinous partition that separates the thorax from the abdomen. It is the chief muscle of inspiration, its central part descending during inspiration. The periphery of the diaphragm is fixed at its points of origin from the ribs, sternum and lumbar vertebra in the form of crura. The muscular fibers converge on the aponeurotic central tendon.
Double-domed

3. Clean and Identify: Inferior Phrenic Arteries
Plate 332
Clean and Identify: Inferior Phrenic Arteries
Inferior Phrenic Arteries
Superior phrenic is a branch of the thoracic aorta.
IVC A
The Pericardiacophrenic, Superior Phrenic, and Musculophrenic arteries also supply the diaphragm

4. Clean and identify the Phrenic nerves
Plate 195
C345…….
Rt. Phrenic Nerve
Clean and identify the Phrenic nerves
Left Phrenic Nerve

5. Motor innervation = Phrenic Nerve
Phrenic nerve containing somatic efferent motor fibers (only motor nerve) and somatic afferent fibers to most of the diaphragm
Plate 193B
Motor innervation = Phrenic Nerve
Sensory = Two sources 1. T5-T12 2. Phrenic Nerve
T5-T12 lower intercostal nerves -sensory to peripheral part of diaphragm

6. Plate 195
Origin
Sternal Origin
Identify the origin of the diaphragm: 1. Sternocostal Origin 2. Lumbar portion: Crura 3. Arcuate Ligaments
Costal Origin
Sternal portion: xiphoid process of the sternum
Costal portion: ribs 7-12 L4

7. Site for hiatal hernias
Plate 195
Origin
Identify the origin of the diaphragm: 1. Sternocostal Origin 2. Lumbar portion: Crura 3. Arcuate Ligaments
Note the right crus passing to the left of the esophageal hiatus: it forms a physiological sphincter for the esophagus
Right Crus
Site for hiatal hernias
Left Crus
Lumbar portion: two crura – right and left crura
Rt. Crus: longer and better developed of the two and usually contributes to the muscular portion of the diaphragm between the aortic and esophageal hiatuses (esophageal sphincter). L2 L3 L4
Look for the splanchnic nerves as they pass through the crura

8. Plate 195
Origin
Identify the origin of the diaphragm: 1. Sternocostal Origin 2. Lumbar portion: Crura 3. Arcuate Ligaments
Median Arcuate Ligament
Medial Arcuate Ligament
Lateral Arcuate Ligament
QL = Quadratus Lumborum
Median arcuate ligament unites the two crura as it passes over the anterior surface of the aorta as it emerges through the diaphragm.
Medial arcuate ligaments are two thickenings of the thoracolumbar fascia that arch superior to the psoas muscles. Extends from the transverse process of L1 to the body of L1 or 2.
Lateral arcuate ligaments are similar to the medial ones but arch over the quadratus lumborum muscle and extend from L1 to the 12th rib. L2 L3
12th rib L4
L1 Transverse Process QL
Psoas

9. Central Tendon of the Diaphragm
Insertion
Plate 195
Central Tendon of the Diaphragm
All of these fibers insert into the central tendon of the diaphragm
This is the central aponeurotic part that is shaped like a cloverleaf

10. Identify the Lumbocostal Triangle
Plate 195
Lumbocostal Triangle
Identify the Lumbocostal Triangle
Site of a Congenital Diaphragmatic Hernia
Lumbocostal Triangle
Lumbocostal triangle is a non-muscular area of variable size between the costal and lumbar parts of the diaphragm. Herniation of bowel can occur with trauma at this site.
5X more common on left

11. Defect in the diaphragm occurs once in 2200 births and is associated with herniation of abdominal contents into the thorax
Gas in bowel
Moore page 330
A posterolateral defect (failure of fusion of the pleuroperitoneal membrane with the septum transversum) of the diaphragm occurs five times more often on the left side than on the right side (liver is in the way). It is located at the periphery of the diaphragm in the region of the lumbocostal (vertebrocostal) triangle. The intestines and occasionally other organs pass through this posterolateral defect of the diaphragm into the thoracic cavity prenatally. This is one type of congenital diaphragmatic hernia (Moore, page 330).
Significant cause of pulmonary hypoplasia/hypertension in infants – 50% do not survive - related to whether the liver has herniated

12. The heart and lungs are compressed and shifted to the right!
If diagnosed before birth, fetal intervention may be possible

13. Clean/Identify the following openings in the diaphragm: T8 T10 T12
Plate 195
Hiatuses
Caval Opening T8
Esophageal Hiatus T10
Clean/Identify the following openings in the diaphragm: T8 T10 T12
Aortic Hiatus T12
1. Hiatus for the inferior vena cava - slightly to the right of midline at the level of T8. Passing through it are:
a. Inferior vena cava
b. Branches of the right phrenic nerve
2. Esophageal hiatus - slightly to the left of midline, and anterolateral to the aortic hiatus, at the T10 level. Passing through this hiatus are the:
a. Esophagus
b. Vagal trunks (anterior and posterior)
c. Anastomotic vessels connecting the vessels of the thoracic esophagus with those of the stomach (left gastric branches)
3. Aortic hiatus - immediately anterior to the vertebral column at the level of T12. The hiatus is formed by the right and left crura of the diaphragm, the median arcuate ligament anteriorly, and the vertebral column posteriorly. Passing through this hiatus are:
a. Aorta
b. Thoracic duct
c. Elements of the azygos and hemiazygos systems of veins
The Aortic Hiatus is formed by the Crura and the Median Arcuate Ligament

14. Painful! “loin to groin”
Plate 341
Ureter 1
Ureter cm
Follow the course of the ureter retroperitoneally
It is narrowed in 3 places where “stones” or calculi can become lodged 2
1. Ureters: They are hollow, muscular tubes for the transport of urine to the bladder that is forced along by peristalsis.
a. In the event that a small body (i.e. kidney stone) starts to pass down the ureter and its passage is impeded, the muscular coat will go into spasm trying to force the stone along. A very severe pain, renal colic, is experienced from "loin to groin" as the stone is passed along the ureter (Moore, pages ).
b. The ureter is relatively narrowed at 3 sites. A ureteric calculus (stone) is likely to lodge in one of these 3 levels: (Plate 341)
1. junction of pelvis of ureter and the abdominal part
2. pelvic brim
3. ureteric orifice at bladder (narrowest)
Painful! “loin to groin” 3
narrowest

15. Also here over the pelvic brim
Stones larger than 3 mm (the diameter of the lumen) are especially painful – distention of the ureter as the muscular coat contracts causes the colicky pain-renal colic
Treatment: Lithotripsy (sound waves), surgery or “passing” of the stone
Fortunately, surgery is not usually necessary to treat kidney stones. Most kidney stones can pass through the urinary system with plenty of water—2 to 3 quarts a day—to help move the stone along. Often, the patient can stay home during this process, drinking fluids and taking pain medication as needed.
Because of their size or location, some stones may not be able to be passed without help. If the stone is high up in the ureter, near the kidney, and is large, then a urologist may need to consider using lithotripsy, or shock wave therapy, to break the stone up into fragments to allow the smaller parts to pass. Shock waves work by vibrating the urine surrounding the stone and causing the stone to break up. Stones that are lodged nearer the bladder do not have surrounding urine to allow this procedure to work and succeed.
The surgeon may also pass a small fiberoptic instrument called a ureteroscope through the urethra and bladder into the ureter. The surgeon then locates the stone and either removes it with a cage-like device or shatters it with a special instrument that produces a form of shock wave. A small tube or stent may be left in the ureter for a few days to help urine flow.
Also here over the pelvic brim

16. Intravenous Urography (Pyelogram)
1. To study the kidneys, ureters, and urinary bladder, a radiopaque medium is injected intravenously (intravenous urography) and serial radiographs are taken at intervals.
2. In retrograde urography, the contrast medium is injected through a catheter that is inserted via a cystoscope into the urinary bladder and the ureter. The contrast medium is usually injected when the tip of the catheter enters the renal pelvis.
Intravenous Urography (Pyelogram)

17. contrast
Kidney stone – calcium oxalate & calcium phosphate = 75-85% of stones; Struvite - second most common (Ammonium magnesium phosphate)
IVP – left kidney is excreting white contrast material but the right kidney is all backed up with no contrast material in the collecting system. A stone is visible at the origin of the right ureter (arrow) producing acute obstruction. The patient presented with typical renal colic.
There is no consensus as to why kidney stones form.
Heredity: Some people are more susceptible to forming kidney stones, and heredity certainly plays a role. The majority of kidney stones are made of calcium, and hypercalciuria (high levels of calcium in the urine), is a risk factor. The predisposition to high levels of calcium in the urine may be passed on from generation to generation.
Geographical location: There is also a geographic predisposition in some people who form kidney stones. There are regional "stone belts," with people living in the Southern United States, having an increased risk. This is likely because of the hot climate, since these people can get dehydrated, and their urine becomes more concentrated, allowing chemicals to come in closer contact and begin forming the nidus of a stone.
Diet: Diet may or may not be an issue. If a person is susceptible to forming stones, then foods high in calcium may increase the risk, however if a person isn't susceptible to forming stones, nothing in the diet will change that risk.
OTC products: People taking diuretics (or "water pills") and those who consume excess calcium-containing antacids can increase the amount of calcium in their urine and increase their risk of forming stones.

18. IVP
There is a stone at the very end of the right ureter where it enters the bladder – note the enlarged right collecting system and ureter (Hydronephrosis and hydroureter).
Hydronephrosis and hydroureter

19. Left Gonadal Vein and Artery Rt. Gonadal Vein and Artery
Plate 341
Gonadal Vessels
Locate the Gonadal artery and vein on both sides L2
Left Gonadal Vein and Artery L3
Rt. Gonadal Vein and Artery

20. Superior Hypogastric Plexus
Plate 318
Try to identify the autonomic nerve plexuses and associated ganglia near the major branches of aorta
Prevertebral Ganglia: Celiac Ganglion and Plexus Superior Mesenteric Ganglion and Plexus
Intermesenteric Plexus
Inferior Mesenteric Plexus and Ganglia
Locate the superior hypogastric plexus: Contains lower lumbar splanchnics and pelvic splanchnics
Superior Hypogastric Plexus

21. Locate the sympathetic trunk and the Paravertebral ganglia
Plate 318
Locate the sympathetic trunk and the Paravertebral ganglia
Paravertebral Ganglia of Sympathetic Trunk

22. Locate and identify some Lumbar Splanchnic nerves
Plate 318
1st, 2nd and 3rd lumbar splanchnic nerves
Locate and identify some Lumbar Splanchnic nerves 1 2
Most lumbar splanchnic nerves join the Intermesenteric and Inferior Mesenteric plexus as well as the Superior Hypogastric plexus
3rd lumbar ganglion
4th lumbar splanchnic nerve

23. Locate the 4 pair of Lumbar Arteries – braches of the aorta
Plate 264
Locate the 4 pair of Lumbar Arteries – braches of the aorta

24. Lumbar Arteries

25. Congenital or acquired weakness
The abdominal aorta may have an aneurysm (AAA)
Congenital or acquired weakness
If recognized, these can be repaired with a Dacron prosthetic graft. If unrecognized, 90% mortality rate because of heavy blood loss. Severe pain in abdomen or back.

26. Remember the transversalis fascia
Plate 263
Identify the muscles of the posterior abdominal wall Q = Quadratus Lumborum P = Psoas Major I = Iliacus Q
Transverse Abdominis P I
a. Psoas major (filet mignon); this long thick fusiform muscle makes a great steak and lies lateral to the lumbar region of the vertebral column. It originates form the lumbar vertebral bodies and tapers down at L5 to join the iliacus muscle further below. The combined iliopsoas muscle passes beneath the inguinal ligament en route to its insertion on the lesser trochanter of the femur.
b. Iliacus; this large triangular sheet of muscle lies along the lateral side of psoas major. It originates from the superior part of the iliac fossa. Most of the fibers join the lateral side of the psoas muscle to be inserted as described above. Both muscles flex the thigh at the hip joint.
1. The iliopsoas muscle has extensive and clinically important relations. If the ureters, kidneys, cecum, appendix, sigmoid colon, pancreas, lumbar lymph nodes or nerves on the posterior abdominal wall are diseased, movements of the iliopsoas may be accompanied by pain.
c. Quadratus lumborum; this is a thick quadrilateral muscle sheet that lies adjacent to the transverse processes of the lumbar vertebrae. It originates from the iliac crest and 2-4 lumbar transverse processes and inserts on the 12th rib. The quadratus lumborum fixes the 12th rib in relation to the pelvis, holding it down against traction exerted by the diaphragm during inspiration. It also flexes the trunk to one side if acting alone, or together, both muscles extend the trunk.
d. Transverse abdominus; this is the third and innermost of the 3 flat muscles of the anterior abdominal wall.
Psoas Minor
Iliopsoas
Remember the transversalis fascia

27. Chyle (lymph) enters blood
Plate 316
Chyle (lymph) enters blood
Find the Cisterna Chyli and the beginning of the Thoracic Duct, the largest lymphatic duct in the body
Thoracic Duct
Cisterna Chyli
It is found between the right crus of the diaphragm and the aorta at L1-2

28. Plate 266
Cisterna Chyli
Cisterna Chyli
Rt. Lumbar Lymph Trunk/Nodes
Left Lumbar Lymph Trunk/Nodes
Intestinal Lymph Trunk(s): from Celiac, SM and IM nodes
Common Iliac Nodes
B. Tributaries of cisterna chyli
1. Paired lumbar lymph trunks - drain lumbar lymph nodes alongside of the lumbar vertebrae; these in turn, receive lymph from the lower extremity, (via external and common iliac chains of nodes), the viscera of the pelvis, kidney and suprarenal glands, and body wall.
2. Single intestinal lymph trunk - receives lymph from intestine, stomach, spleen, pancreas, and liver. This lymph first passes to nodes associated with viscera and then runs in vessels that parallel major blood vessels to the intestinal lymph trunk.
It receives three tributaries; Intestinal Lymph Trunk Rt. and Left Lumbar Lymph Trunks

29. Iliohypogastric Ilioinguinal Lat. Femoral Cutaneous L2-3
Plate 498A
Subcostal Nerve
T12
This is the Lumbar Plexus formed by ventral rami of L1 – L3 and 1/2 of L4 L1
Iliohypogastric Ilioinguinal
Genitofemoral L1-2 L2
Lat. Femoral Cutaneous L2-3 L3 L4
Subcostal nerve is the 12th intercostal nerve.
Femoral Nerve L2-4 L5
Accessory Obturator Nerve
Obturator Nerve L2-4
Anterior Division
Posterior Division

30. These are SOMATIC NERVES! Lumbosacral trunks (1/2 L4-L5)
Plate 498B
These are SOMATIC NERVES!
Identify the following branches of the lumbar plexus
Subcostal T12
Transect the Psoas Major and identify the rest of the branches L1
Iliohypogastric & Ilioinguinal L1 L2 L3 L4
Lat. Femoral Cutaneous L2,3 L5
4. Lumbar plexus (ventral rami of L1-3, 1/2 L4) (Plate 267)
a. Branches
1. ilioinguinal and iliohypogastric (L1)
2. genitofemoral nerve (L1-L2)
a. Femoral branch: passes beneath inguinal ligament within
femoral sheath and supplies skin over the femoral triangle.
b. Genital branch: runs to the deep inguinal ring and traverses the inguinal canal to supply the cremaster muscle.
3. lateral femoral cutaneous nerve (L2-3)
a. supplies skin over lateral and anterior thigh
4. obturator nerve (L2-4)
5. femoral nerve (L2-4)
6. lumbosacral trunk (L4 [1/2], L5): descends into the pelvis to join the 1st sacral nerve (helps form the sacral plexus).
Genitofemoral L1,2
Lumbosacral trunks (1/2 L4-L5)
Femoral L2-4
Obturator L2-4

31. Nerves course between the IO and TA T7-T12 intercostal nerves and L1
Plate 257
Abdomen
Nerves course between the IO and TA
T7-T12 intercostal nerves and L1 T7
T10
IliohypogastricNerve (L1)
Motor to muscles and sensory to skin and peritoneum
T12 L1
Ilioinguinal Nerve (L1)

32. Laboratory/Quiz