7 - Diaphragm, Kidneys, and Posterior Abdominal Wall

What is the principal muscle of respiration?

the diaphragm

Gross features of the Adrenal gland (think kidney)

- Fibrous capsule - Adrenal cortex = outer portion, produces adrenal steroids. Contains 3 zones. - adrenal medulla = inner portion, acts as sympathetic ganglion (modified neuronal cells). Contains medullary/chromaffin cells that release epinephrine & norepinephrine

Describe the layers of the kidney from fibrous capsule (most superficial) to Ureter (deepest)

- Fibrous capsule - Renal cortex = outer 1/3 - Renal medulla = inner 2/3 - contains renal pyramids and columns - Renal papillae (receives apex of pyramids) - Minor calyces - Major calyces - Renal pelvis - Ureter

What are the fat pads and fascia associated with the kidney?

In the retroperitoneum, kidneys are surrounded by renal fascia. The fascia divides the more superficial paranephric fat pad and the more deep perinephric fat pad which continues into the hilum.

What demarcates the abdominal aortic bifurcation?

L4 at the level of the umbilicus. (Remember, innervation of cutaneous umbilicus is T10)

Lumbosacral Trunk: Cord level, Location, Innervation

L4-L5 Large nerve trunk that crosses over ala of sacrum and descends into pelvis to help form sacral plexus. Provides contributions to both plexuses

Kidneys in dissected view

Notice the vasculature asymmetry due to Aorta and Vena Cava

ID of Inferior Phrenic Artery on dissection

Paired inferior phrenic arteries off the aorta

Nerves in the diaphragm and their associations

Right phrenic nerve, associated with the inferior vena cava Left phrenic nerve, which passes directly through the diaphragm. Innervates both superior and inferior aspects of the diaphragm.

Describe the length and path of the renal arteries and veins

Right renal a. is longer than the Left and passes posterior to IVC. Each divides at the hilum into segmental aa. (end aa.) Renal veins to IVC are anterior to the renal aa. Left vein is longer and passes anterior to the aorta.

Describe the vascularization of the adrenal glands. Which arteries do the suprarenal arteries arise from?

Suprarenal aa. - 3 sources 1. superior suprarenal aa. (6-8 br) - inferior phrenic a. 2. middle suprarenal aa. (1+ br) - abdominal aa. 3. inferior suprarenal aa. (1+ br) - renal aa.

Subcostal Nerve: Cord level, Location, Innervation

T12 About 1 cm inferior to 12th rib Supplies sensory to anterior/lateral abdominal wall Supplies motor to abdominal muscles: External & Internal Obliques, Transversus Abdominis, Pyramidalis, Rectus Abdominis, Quadratus Lumborum

Describe the vasculature of the ureters

Ureter arteries rise from 3-4 sources: - renal a. - testicular or ovarian a. (gondal a.) - abdominal aorta or common iliac a. - internal iliac a. the veins drain into similarly named vv.

What are the apertures of the diaphragm? Costal levels?

Vena cava foramen - T8 (IVC) Esophageal hiatus - T10 (esophagus) Aortic Hiatus - T12 (aorta)

Nerves of the lumbar plexus: Cord levels & Branches

Ventral rami of T12-L4. T12: Subcostal L1: Iliohypogastric & Ilio-inguinal L1 & L2: Genitofemoral nerve L2 & L3: Lateral cutaneous nerve of thigh L2-L4: Obturator nerve & Femoral nerve L4-L5: Lumbosacral trunk

What are the arcuate ligaments/lumbocostal arches?

1 median arcuate ligament: arches over aorta 2 medial arcuate ligaments: arch over psoas mm. 2 lateral arcuate ligaments: arch ver quadratus lumborum mm.

What are the muscles of the posterior body wall?

1. Transversus abdominis m. 2. Quadratus lumborum m. 3. Psoas major m. 4. Iliacus m. 5. Psoas minor m. 6. Diaphragm

The lumber arteries include ___ branches off the _______ ______, superior to its bifurcation into the common iliac arteries.

4 pairs of arteries. Branches off the abdominal aorta, superior to its bifurcation into the common iliac arteries

Where does the phrenic nerve arise from in the spinal cord?

A portion of the cervical plexus - C3, C4, C5 with both motor and sensory components. (C3, 4 and 5, keep me breathing and alive)

Describe the sensory/motor innervation pathway of the phrenic nerve.

Both sensory and motor nerves descend around pericardial sac. There are central and peripheral aspects. Motor (green) is mostly central. Sensory (purple) is central AND peripheral (follows down along the rib cage).

Iliohypogastric & Ilioinguinal Nerves: Cord level, Location, Innervation

Can arise from the same trunk (L1) Descend anteriorly to Quadratus Lumborum (lateral to psoas major) Iliohypogastric n: supplies skin of suprapubic region Ilioinguinal n: runs through inguinal canal and supply it Both supply the abdominal mm.

How can we ID the phrenic nerve?

In the anterior, it is associated with the anterior scalene muscle

What is different about the renal arteries?

Each arterial segment does not anastomose with the other arterial segments. If one segment of the kidney is injured or dies, the rest of the kidney can still function.

The _____ nerve and ______ nerve supply both deep innervation and follow the dermatome map.

Femoral nerve and obturator nerve (L2-L4)

What are the zones of the adrenal cortex and their associated hormones?

From outermost to innermost: Zona glomerulosa: main site for production of mineralocorticoids, mainly aldosterone Zona fasciculata: produces glucocorticoids, such as cortisol. Zona reticularis: produces androgens, mainly DHEA

What type of pain occurs with calculi? How does it progress?

Individuals passing calculi (kidney stones) experience referred, rhythmic pain that arise from waves of contraction that force the stone down through the ureter. It gradually moves inferioanterograde. From side, to back, between ribs, to pelvis, to the inguinal area (area of cutaneous innervation T11-T12 & L1).

We see action of the phrenic nerve with expiration/inspiration? Is the innervation bilateral or hemilateral? What does this mean clinically?

Inspiration. It is innervated in hemilateral (or unilateral) sections. A paralyzed hemidiaphragm will result in unilateral inability to contract. This aspect will remain high in the thorax during inspiration, and can be seen on chest x-rays.

What are ectopic kidneys? What are the types?

Kidneys that remain in the pelvis during development. Can be ectopic pelvic kidney that remains anterior to sacrum or ectopic horseshoe kidney that remains fused across the midline and below Inferior Mesenteric Artery (IMA).

What are the costal levels of the superior poles of the kidneys? Are they same? Why or why not?

L kidney at 11th rib R kidney at 12th rib Different due to large liver on right side

Genitofemoral Nerve: Cord level, Location, Innervation

L1-L2 Pierces psoas major and descends along anterior surface. Splits into femoral and genital branch. Supplies skin inferior and medial to inguinal ligament. Supplies cremaster m. of the spermatic cord in males.

Lateral Femoral Cutaneous Nerve: Cord level, Location, Innervation

L2-L3 Descends anteriorly to iliacus m. and lateral to the Psoas Major m. Passes deep to the inguinal ring and inferior to ASIS. Supplies anterior/lateral skin of thigh

Femoral Nerve: Cord level, Location, Innervation

L2-L4 Runs between iliacus and psoas major mm (very deep). Passes deep to inguinal ligament and inferior to ASIS. Can be seen in femoral triangle. Supplies sensory and motor to anterior thigh.

Obturator Nerve: Cord level, Location, Innervation

L2-L4 Runs medial to Psoas Major and passes through obturator foramen. Supplies sensory and motor to medial thigh.

Vessels of the diaphragm. Supply for each?

Pericardiacophrenic & superior phrenic aa. - Supply superior surface (via internal thoracic aa. and thoracic aorta) Inferior phrenic aa. - Supply inferior surface (via abdominal aorta) Musculophrenic aa. - Supply periphery of diaphragm (via internal thoracic aa.) Venous drainage is via accompanying vv. to IVC

Adrenal Glands - Shape and Anatomical Position

R gland - roughly triangular and lies superiorly to R kidney, posterior to IVC L gland - more semilunar and lies superomedial to L kidney near hilum

Describe the drainage of Kidney/Urine

Renal papillae receive urine at apex of pyramids - to minor calyces - to major calyces - to ureter - to urinary bladder - to urethra

What structures define the borders of the diaphragm?

The tendinous attachments of the arcuate ligaments inferiorly/posteriorly. Anterior/peripheral tendinous attachments to the costal margins. Also, a central tendinous aponeurosis transversely.