Posterior Abdominal Wall1. Identify. For each muscle identify attachments, innervations, and action.

A- 12th ribB- AC- la of the sacrumD- Iliac fossaE- Iliac crestF- Lumbar vertebrae (lumbar vessels)

Muscle Attachment Innervation Action

A

B

C

D

EF

G

H

I

Psoas Minor (F) T12-L1, binds to superior pubic ramus

None Only appears in some people, no real function

Psoas Major (G) T12, lumbar vertebrae and intervetebral discs, lateral sides of lumbar vertebrae, lesser trochanter on femur.

Ventral rami of L1-L3

Flexes the leg at the hip joint

Iliacus (H) Iliac fossa, ala of sacrum, sacroiliac ligament

Femoral nerve (L2-L4)

Flexion of thigh, lateral rotation of thigh.

Quadratus Lumorum (I)

Superior-12th rib; Medially-TVP of lumbar vertebrae, illiolumbar ligament (occurs between TVP of L5 and iliac spine)Inferior-Iliac Crest

Ventral Rami of T12-L4

Unilateral-lateral flexion of trunk; Bilateral-Extension of trunk

2. What is the illiopsoas? What is the illiopsoas test?

The illiopsoas is the “combination” of the illiacus muscle and psoas muscle, considered because the muscles are so close to each other. The illiopsoas test tests for irritation in these muscles, can be caused by an inflamed appendix.

3. Identify and describe

A- Quadratus Lumborum muscleB- Psoas muscle

A

B

CD

EFG

H

I

J

C- Left Crus of diaphragmD- Lumbar vertebraeE- Erector spinae muscleF- Middle fascia (formed by erector spinae muscle)G- Posterior fascia (formed by erector spinae muscle)H- Thoracolumbar fascia-formed by combination of the erector spinae fascias (middle and posterior) and the

anterior fascia provided by quadrates lumborumI- Anterior fascia (formed by Quadratus lumborum )J- Internal oblique/Transversalis abdominis muscles

4. How does a psoas abcess form?It forms when an infection occfurs at the lumbar vertebrae. When this happens, the infection will travel along the psoas muscle, but will be contained by the psoas fascia. This will keep the infection contained until it gets down to a break in the fascia at the thigh, where it will penetrate the skin and form an abcess at the thigh.

5. Label and describe. Special fact about L, M, N

A- Inferior Vena cavaB- Phrenic nerve- It innervates the deep surface of the diaphragmC- Central Tendon of diaphragm- various openings are here including to the IVCD- Superior epigastric artery coming through the sternocostal hiatusE- Lumbocostal triangle- Gap in the skeletal muscle fibers, herniations occur here frequentlyF- Greater splanchnic nerve- runs along the right and left crus

A

B C

D

F

G

H

E

IJ

K

L

M

N

G- Attachment of the left crus- This crus is smaller than the right crus, it attaches to L1 or L2. The ligament of Treitz goes through this crus

H- Attachment of the right crus- Comes down to L1-L3 and wraps around the esophagus to form the muscular portion of the esophageal sphincter, it is usually lower than the left crus.

I- Quadratus Lumborum muscle traveling through the lateral arcuate ligamentJ- Psoas muscle traveling through the medial arcuate ligamentK- Muscular portion of the diaphragmL- Medial arcuate ligament-the psoas muscle travels through here. It is formed by the fascia of the

psoas muscle. Goes from L3 to the transverse process of L1M- Lateral arcuate ligament-the quadratus lumborum muscle travels through here, it is formed by the

fascia of the quadratus lumborumN- Median arcuate ligament-Formed by the tendinous fibers connecting right and left crus, the aorta

travels through hereThe arcuate ligaments represent an attachment point for the muscular part of the diaphragm.

6. What causes hiccups?Hiccups are caused by irritation of the phrenic nerve, this leads to the diaphragm spontaneously contracting.

7. How do the Inferior Vena Cava, Esophagus and Aorta go through the diaphragm? What is the special connection between diaphragmatic contraction and function of these 3 things?

IVC comes through diaphragm at T8, Esophagus at T10 and Aorta at T12. When the diaphragm contracts, it impacts IVC function greatly. During contraction, the pressure inside the abdomen is increased while the pressure inside the thorax is decreased, therefore, this will pump blood up through the IVC and towards the heart. The esophagus and aorta do not move much when the diaphragm contracts because they are located more posteriorly.

8. What neurons provide sensory input from the diaphragm? What neurons provide motor inputs from the diaphragm?

Sensory information related to the diaphragm is provided by the afferent phrenic nerves (C3-C5) and the subcostal and intercostals nerves. Motor innervations to the skeletal muscles of the diaphragm is provided by the phrenic nerve (C3-C5)

9. What is the referred pain that can occur if the nerves of the diaphragm are irritated? Describe

The referred pain that occurs happens in the shoulder, this is because the phrenic nerve is provided for by C3-C5, therefore it shares innervations with the shoulder nerves and can lead to shoulder pain.

10. What can occur with a lesion to the phrenic nerve?

If the phrenic nerve is cut, it can cause paradoxical movement of the deinervated side. If one side is cut and one side is normal, the innervated side will move properly downwards while the deinervated side will move improperly upwards.

11. How does the heart affect the diaphragm shape?

The pericardium depresses the diaphragm slightly, creating 2 hemispheres on either end.

12. Describe the 4 arteries and veins that supply the diaphragm.

a. Pericardiacophrenic- Comes off internal thoracic Travels through the diaphragm along with the phrenic nerve, it supplies the middle region of the diaphragm

b. Musculophrenic- Branches off the internal thoracic arteries, supplies the anterior diaphragm. c. Superior phrenic- Comes of the abdominal aorta before it goes through the diaphragm. It supplies the

posterior diaphragm on the superior surface. d. Inferior phrenic- Comes off the abdominal aorta immediately after crossing the diaphragm. It supplies the

posterior diaphragm on the inferior surface

13. Identify and describe 1-3.

1. Unpaired visceral arteries (eg. Superior/Inferior mesenteric, celiac trunk, etc.)2. Paired visceral arteries (eg branches to kidney, suprarenal gland)3. Paired parietal arteries (eg. Arteries that supply the muscles of the abdominal cavity)

14. Label and describe the arteries

A

B

C

D

E

F

G

H

I

A-Inferior phrenic arteryB-Right renal artery- Goes to kidneys-located at L1C-Lumbar arteries-supplies the lumbar vertebrae, spinal cord, posterior abdominal wallD- Bifurcation of the aorta-occurs approximately at L4E-Median sacral artery-occurs only in some people, supplies median surface of the sacrumF- Internal iliac artery-branch off the common iliac arteryG- External iliac-branch off the common iliac arteryH- Femoral artery-Continuation of the External iliac artery after crossing the inguinal canal. I- Common iliac (left)-One of the 2 branches (the other is the right common iliac) of the abdominal aortaJ- Left gonadal artery-branches off aorta at L2

15. What is an aortic aneurysm?

Any kind of aneurysm is weakness in the wall of the aorta, when it occurs in the abdomen, you can see pulses of the aorta that are in conjunction with the beating heart.

16. Label the veins that come off the inferior vena cava.

A/B- Left and Right hepatic veins- they drain the liver, closeness is seen because the liver runs up directly on the inferior vena cavaC- Left phrenic vein-drains the diaphragmD- Right renal vein-shorter vein because displacement is not an issueE- Bifurcation of the IVC at L5

A B

C

D

E

FG

H

I

F- median sacral vein-drains the sacrum, this vein is shifted to the right because the IVC is shifted to the left, this point represents the location of the median sacrumG/H- External/Internal iliac veins- same pattern as arteriesI-Left renal vein- Extended because IVC is towards the right, so it needs to extend further. There are numerous branches that drain into this vein instead of draining into the IVC.

17. Describe the abdominal lymphatic system.

There are lymph nodes all over the place, they can be characterized into 2 main categories, visceral nodes and parietal nodes. Visceral nodes drain the viscera of the abdomen and will follow associated arteries and veins. Parietal nodes drain the abdominal wall and large arteries. Lymph flows from the visceral nodes to the parietal nodes then to the cisternae chyle. The cisternae chyle is the convergence of the lymphatic trunks located between the psoas muscle and the IVC at L1 and L2 vertebrae. Lymph then flows from the cisternae chyle to the thoracic duct. The lymph then goes into the thorax and drains into the venous system there.

18. What makes up the lumbar plexus?

The lumbar plexus is formed by ventral rami of L1-L5, it provides sensory innervations to the skin and motor innervation to the muscle of the abdominal wall. It does NOT provide anything to the viscera of the abdomen. It is located around the psoas muscle.

19. Identify the nerves (and their origins) of the lumbar plexus. Describe their path thru the leg.

A- Iliohypogastric (L1)- Travel on anterior surface of psoas muscleB- Ilioinguinal (L1)-Travels on anterior surface of psoas muscleC- Genitofemoral (L1/L2)-Travels medially along the posterior abdominal wall, and along the surface of psoas

major. Around the inguinal ring, the nerve splits into a genitor branch (to supply the cremaster muscle in males and labia majora in females) and a femoral nerve to supply the thigh.

D- Lateral femoral cutaneous (L2/L3)- supplies skin on lateral aspect of upper thighE- Femoral (L2-4)-supplies the iliacus muscle, travels under the inguinal ligament to supply the quadriceps muscle

and thigh. F- Obturator (L2-4)- Drops into pelvic cavity on the medial side of the psoas. Innervates the ADductors of the thigh.

G

FE

D

C

B

A

G- Lumbosacral trunk (L4-L5)- Drops very deep into sacrum joins the sacral plexus. Lumbar contributions to the sacral plexus.

20. Label the dermatome map.

A- T12 and L1-subcostal,illiohypogastric nervesB- Femoral branch of genitofemoral nerveC- Ilioinguinal nerveD- Obturator nerveE- Lateral Cutaneous nerve of thighF- Intermediate Cutaneous nerve of thighG- Medial Cutaneous nerve of thigh

21. What are the functions of the kidneys?

The function of the kidney is to remove excess water, salts and nitrogenous waste from the blood to produce urine. This urine is carried by the ureters to the bladder to be excreted.

22. What are places where the ureter narrows? What is special about these places?

The ureter narrows in three locations:a. At the pelvic region as the ureter is leaving the hilusb. When the ureter crosses over the common iliac vesselsc. When the ureter is about to enter the urinary bladder The special fact about these spots is that these are the locations where kidney stones are most common.

23. What is a kidney stone? What is the referred pain associated with kidney stones?

A

B

C

D

E

F

G

A kidney stone is composed of organic salts that precipitate out of urine and remain stuck to the ureter. These salts will irritate the nerve supply (T11-L2) of the kidney. As the kidney stone moves through the ureter, you can start with referred pain in the back region, but then it moves to the groin region as the kidney stone itself moves.

24. Where is the kidney located?

The kidney is a retroperitoneal organ that is located on the posterior abdominal wall, located around T12 to L3. The hilum of the left kidney is at L1, while the hilum for the right kidney is lower, this is because the liver is so large that it depresses the kidney

25. Label the following diagram, describe each term.

A- Cortex- Glomeruli are found here, the capillaries extend and this is where filtration beginsB- Renal columns- Glomeruli that extend into the sinusC- Medualla/Renal pyramids- parts of the medulla will form in between the renal columns. At the top of the

pyramid is an apex that is continuous with the renal sinus. D- Minor calyx-cup like structure that surrounds the apex of each pyramid. E- Major calyx- 2-3 minor calyx come together to form major calyxF- Renal sinus- This is the entire cavity that the hilus opens up into. The renal sinus consists of the major and

minor calyx, renal artery and vein. The renal sinus contains the renal pelvis, fat, and autonomic nerves. G- Renal pelvis-First part of ureter, also where all major calyx come together. H- Renal Hilus- Point of entry for the ureter and renal blood vessels.

26. What are renal cysts?

Renal cysts form when there is a blockage in the glomeruli. This prevents fluid from going towards the hilum and therefore, fluid will build up in the glomeruli.

A

BC

D

E

F

G

H

27. Describe and label the renal coverings.

A- Perirenal fat- Located on the outside of the capsule, it is continuous with the fat in the sinus. B- Parietal peritoneumC- Pararenal or paranephric fat- Fat that surrounds the kidney but is located within the renal fasciaD- Renal fascia- Continuous with transversalis fasica laterally and psoas fascia medially. E- Surgical pathway to enter the kidney. This diminishes infection to other parts of the abdomen because it is not

opened up. F- Fibrous capsule- Capsule that surrounds kidney.

28. What are suprarenal glands? What are the 2 major parts and their functions? Where are they located? What is the arterial supply, venous drainage and innervation?

Suprarenal glands are glands located on the superior pole of the kidney, each one is covered by a thin fibrous capsule and is continuous with renal fascia.

Functions: Cortex- produces and secretes corticosteroids and androgens.Medulla - Chromaffin cells produces and secretes catecholamines (epinephrine andnorepinephrine)The chromaffin cells are innervated by preganglionic sympatheticfibers of the greater splanchnic nerve.

Location: Retroperitoneal, along the posterior abdominal wall near vertebral level T11. Betweenthe superomedial aspect of the kidney and the diaphragm.Surrounded by its own fibrous capsule (separate from the fibrous renal capsule) aswell as by the perirenal fat, renal fascia and pararenal fat.

A

B

C

D

F

E

Arterial Supply: Superior suprarenal artery - branch off of inferior phrenic arteryMiddle suprarenal artery - branch off of abdominal aortaInferior suprarenal artery - branch off of renal artery

Venous drainage: Left suprarenal vein drains into the left renal veinRight suprarenal vein drains into the inferior vena cava

Innervation: greater splanchnics