RA week 6 Flashcards
retroperitoneal?
structure lies posterior to parietal peritoneum
examples of retroperitoneal structures?
primary = develops posterior to peritoneum i.e. kidneys, suprarenal glands, vessels, nerves secondary = become covered in peritoneum by end of development i.e. most of duodenum, pancreas, ascending colon, descending colon, upper 2/3 rectum
…
surface anatomy kidneys?
hilum of kidneys = L1
each kidney is 10-12cm long and 6-8 cm wide
relations of right kidney?
is it higher or lower than left kidney?
Anterior = suprarenal gland, liver, 2nd part duodenum, R colic flexure Posterior = diaphragm, rib 12, psoas, quadratus lumborum, transversus abdominis, subcostal nerve
lies slightly lower than the left due to liver
relations of left kidney?
Anterior = suprarenal gland, spleen, stomach, pancreas, left colic flexure, jejunum Posterior = diaphragm, ribs 11 and 12, psoas, quadratus lumborum, transversus abdominis, subcostal nerve
(higher than right + protected by ribs 11 + 12, also sits on muscles of posterior abdominal wall)
kidney surrounded by?
hilum contains?
function?
smooth outer capsule
hilum = renal vein, branches of renal artery, renal pelvis (becomes ureter), lymph + sympathetic fibres
filtration of blood to create urine
…
calyces collect urine and channel it to renal pelvis which becomes ureter and carries it to bladder
blood supply to kidneys?
where do they pass?
which one is longer? why? where does it pass?
arteries divide into?
renal arteries from aorta (L1) - usually divides into anterior + posterior branches then into segmental branches that ente rhilum
Right renal artery longer as has to travel from aorta (left) - passes posterior to inferior vena cava (IVC)
Lobar arteries, interlobar arteries, arcuate arteries, afferent glomerular arterioles inside kidney
venous drainage kidneys?
lymph?
nerves? level?
renal veins to IVC
lymph = para-aortic nodes around origin of renal arteries (lateral)
nerves from renal sympathetic plexuses, afferent fibres enter spinal cord at T10-12
which renal vein is longer? why?
where does it pass?
what drains into left renal vein?
where does right renal vein pass?
right gonadal vein?
left renal vein 3x length of right as it passes from left kidney to reach the IVC (right of vertebral bodies)
left renal vein passes behind splenic vein and pancreas + inferior to superior mesenteric artery
left gonadal + left suprarenal vein drain into left renal vein
right renal vein passes behind duodenum
right gonadal vein drains directly into IVC
where do ureters pass?
pass down from hilum (posterior to parietal peritoneum) on surface of psoas to bladder
crosses bifurcation of common iliac artery anterior to sacro-iliac joint
descend down lateral wall of pelvis towards ischial spine
enter inferior surface of bladder at trigone
how is urine propelled through ureters?
contractions of ureter wall + filtration pressure from glomeruli
constrictions of ureters?
Thiel image also shows nerves from the lumbar plexus and other structures that can be mistaken for the ureters. It is important to remember that the ureters cross the bifurcation of the common iliac artery as they enter the pelvis, as this landmark will help you identify the ureters more easily.
The arrows on the radiograph show the ureters passing down the abdominal wall. The psoas muscles cannot be seen so the ureters are described as passing the tips of the transverse processes of the lumbar vertebra. The dye appears uneven in the ureters as the ureters contract to help push the urine towards the bladder. The bladder can also be seen on this image as it slowly fills with radio-opaque dye.
blood supply to ureters?
venous drainage?
change from proximal to distal as ureter descends into pelvis
arteries
- proximal = renal artery
- middle = testicular/ovarian artery
- distal = superior vesical artery
veins correspond to arteries
lymph drainage ureters?
nerves?
pain referred?
Lymph to para-aortic node sin abdomen + iliac nodes in pelvis
nerves
- proximal = renal
- middle = testicular/ovarian
- distal = hypogastric plexus
afferent fibres to L1 + L2 so pain referred to inguinal region at top of the thigh (pic)
suprarenal glands found?
layers?
what shape is right gland?
left gland?
relations?
- Superior pole of kidney – yellow cortex, brown medulla
- Cortex = corticoids (fluid, electrolyte); glucocorticoids (carbohydrates, fats, proteins)
- Medulla = epinephrine and norepinephrine
- Right = pyramidal, behind right lobe of liver
- Left = cresenteric, behind pancreas, stomach and lesser sac
blood supply to suprarenal glands?
venous drainage?
3 arteries on each side = superior suprarenal branch of inferior phrenic artery, middle suprarenal branch direct from aorta, inferior suprarenal branch of renal artery
veins = single vein on each side, R drains to VC, L drains to renal vein
lymph drainage suprarenal glands?
nerves?
para-aortic nodes same as kidneys
nerves = sympathetic from splanchnic nerves (most end in medulla)
other retroperitoneal structures?
aorta, IVC, gonadal vessels, sympathetic chain, cysterna chyli, muscles of posterior abdominal wall
fascia of abdominal wall?
names?
continuous with?
layer of connective tissue between peritoneum and abdominal wall muscles
named after muscles e.g. fascia over quadratus lumborum
continuous with fascia of pelvis
what does abdominal wall fascia form?
after arcuate line?
in inguinal region forms femoral sheath that surrounds femoral artery + vein
transversalis fascia (deep inguinal ring) continues as internal spermatic fascia of spermatic cord
after arcuate line = fascia behind rectus abdominus is transversalis fascia
quadratus lumborum?
attachments?
fucntion?
innervation?
quadrangular muscle in lumbar region
iliac crest → 12th rib + L1-L4 transverse process
one = bends trunk to same side
both = pressure, forced expiration + support for 12th rib
innervation = T12-L4 anterior rami
fascia over quadratus lumborum?
thickened near diaphragm to form lateral arcuate ligament
iliacus attachments?
function?
innervation?
from iliac fossa → joins psoas to form iliopsoas then attaches to lesser trochanter of femur
hip flexion
femoral nerve
psoas attachments?
function?
innervation?
from T12-L5 bodies → join iliacus to form iliopsoas and attach to lesser trochanter of femur
hip flexion, bend trunk laterally (one), raise trunk from supine position (both)
lumbar plexus direct branches L2-L4
fascia over psoas function?
fascia over psoas is thickened near the diaphragm to form medial arcuate ligament
muscles of the posterior abdominal wall?
quadratus lumborum
iliacus
psoas
transversus abdominus
crura of the diaphragm
how does abdominal aorta enter abdomen?
branches?
at what level does it bifurcate?
through aortic hiatus of diaphragm (T12)
branches to: diaphragm (inf. phrenic), abdominal wall (lumbar, median sacral), abdominal viscera, kidneys, ovaries/testes
bifurcates @L4 into common iliac to supply lower limb + pelvis
anterior, lateral + terminal branches of abdominal aorta?
inferior vena cava tributaries?
forms at what level?
drains to?
drains posterior body wall (lumbar, sacral), diaphragm (inf. phrenic), kidneys, supra-renal glands + hepatic veins
(veins that drain blood from gut tube pass blood to portal system (not IVC), blood from portal system passes through liver before entering IVC via hepatic veins)
left + right common iliac veins unite @L5 to form IVC
through diaphragm @T8, drains into RA
tributaries IVC?
difference from aorta?
unlike aorta, IVC lacks large anterior branches
lumbar veins?
drain into?
variation?
drain the posterior abdominal wall
L1 + L2 = drain into ascending lumbar vein
L3 + L4 into IVC
L5 into iliolumbar vein (into common iliac)
ascending lumbar veins connect external iliac + lumbar veins to azygos + hemiazygos veins
creates pathway for venous return that doesn’t use IVC
if person has variation called interrupted IVC where part of IVC does not form, this route for venous return may become swollen
gonadal vessels?
gonadal arteries?
veins?
called ovarian in females + testicular in males
arteries direct from abdominal aorta @L2
drain directly into IVC on right side but into left renal vein on left side
lymphatics posterior abdominal wall?
lymph from pelvis = iliac nodes
para-aortic nodes = body wall, kidneys, testes/ovaries
pre-aortic = digestive tract i.e. coeliac (T12), SM (L1), IM (L3)
intestinal trunk (with swelling called cisterna chyli) = lymph from intestines all drains into here then thoracic duct
…
sympathetic plexuses post. abdo wall?
parasympathetic fibres?
greater splanchnic nerve (from symp chain in thorax) + lumbar splanchnic nerves (from symp chain in abdomen) give fibres to coeliac, superior mesenteric + inf. mesenteric plexuses
parasymp fibres from vagus + pelvic splanchnic nerves (S2, S3, S4)
what other plexuses exist other than coeliac, SM and IM?
where are they found?
parasymp to gut?
superior + inferior hypogastric plexuses - carry sympathetic and parasympathetic fibres
superior plexus sits at bifurcation of the aorta (L4)
inferior hypogastric plexus on both lateral walls of pelvis
vagus nerve carries parasympathetic fibres to foregut + midgut but hindgut receives parasympathetic innervation from pelvic splanchnic nerves instead. The inferior hypogastric plexuses also carry autonomic fibres to pelvic organs
lumbar plexus composed of?
where is it found?
function?
anterior rami L1-L4
plexus lies underneath psoas
some sensory supply to skin of pelvis but mostly motor + sensory to lower limb
nerves of the lumbar plexus?
also forms?
landmark?
from superior to inferior = iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral + obturator nerves
also forms lumbosacral trunk which carries L4 + L5 fibres into pelvis to join with sacral nerve roots (giving rise to sciatic nerve etc)
Also seen on the diagram s the subcostal nerve. This originates from T12 so is not part of the plexus but is a large nerve that lies immediately inferior to rib 12. This makes it an easy landmark to identify during dissection that can guide you to the iliohypogastricand ilioinguinal nerves that form from L1 nerve roots.
iliohypogastric + ilioinguinal nerve roots?
functions?
both from L1 anterior ramus
iliohypogastric = sensory to lateral gluteal + pubic skin, motor to internal oblique + transversus abdominis
ilioinguinal = sensory to skin on medial thigh + root of penis/scrotum or mons pubis/labium majora; motor to internal oblique + transversus abdominis
genitofemoral nerve roots?
found?
branches?
function?
anterior rami L1 + L2
genitofemoral nerve runs along anterior surface of psoas
divides into femoral + genital branch
femoral = sensory to skin of upper anterior thigh
genital = sensory to perineum (scrotum/mons) + motor to cremasteric muscle
lateral cutaneous nerve of thigh roots?
function?
also called?
anterior rami L2 + L3
sensory = skin of anterior + lateral thigh (above knee)
also called lateral cutaneous femoral nerve
largest nerve from lumbar plexus?
roots?
function?
how does it reach this?
femoral nerve (L2, L3, L4)
sensory + motor
sensory = anterior thigh + medial side of leg via saphenous branch
motor = pectineus, iliacus, anterior compartment of thigh e.g. quads
to reach ant. compartment it passes under inguinal ligament and into femoral triangle
obturator nerve roots?
pathway?
function?
same roots as femoral - L2, L3, L4
passes close to sacrum + into pelvis where it passes thru obturator muscles + membrane of obturator foramen
takes nerve into medial compartment of thigh = supplies sensory to medial thigh skin + motor to obturator externus and medial compartment of thigh e.g. gracilis
kidneys are retroperitoneal structures protected by a peri-renal fat pad – as shown in photograph A. If the fat was removed from the area shown by the white dotted lines then the right kidney and associated structures would be visible. Photograph B shows the right kidney and vessels at the renal hilum following removal of the fat pad
Photograph A shows the left kidney and suprarenal gland. The surface of the kidney should be smooth, but there are small circular cysts visible on the lower pole of the kidney in this individual. The renal artery, renal vein and renal pelvis/ureter are found at the hilum of the kidney.
Photograph B shows a close-up view of the left suprarenal gland – it is described as crescent shaped in textbooks but will deform as you remove the tissue surrounding the gland during dissection. The suprarenal glands are usually a yellow/orange colour following Thielembalming.
Photograph A shows the right kidney and its associated vessels. The capsule is thickened in this individual and has been peeled from part of the anterior surface during dissection to reveal the red/brown surface of the kidney. This kidney also shows an anatomical variation – there is an accessory (supernumerary) renal artery to the upper pole of the kidney. Variant renal veins are rare but variation of renal arteries is more common.
Photograph B shows the right suprarenal gland, it is described as pyramid shaped in textbooks but this shape is less evident during dissection, especially after removal of the liver.
The renal arteries divide at the hilum into anterior and posterior branches and then into segmental arteries. This is shown in photograph A with the anterior and posterior branches of the left renal artery labelled A and P respectively.
The renal arteries are direct lateral branches of the abdominal aorta at L1 vertebral level. The renal veins drain directly into the inferior vena cava (IVC). Photograph B shows the right renal artery emerging from the aorta and the right renal vein draining into the IVC.
The left renal vein is longer than the right and crosses the aorta to reach the IVC. The left suprarenal vein and left gonadal veins drain into the left renal vein. The right gonadal vein drains directly into the IVC.
Urine is made in the kidney and passes into major and minor calyces before flowing into the renal pelvis and then into the ureter towards the bladder. Photograph A shows the left ureter as a continuation of the renal pelvis at the hilum of the kidney.
The ureter is a retroperitoneal structure as it descends the posterior abdominal wall and crosses the anterior surface of psoas muscle. The right ureter on the surface of psoas is shown in photograph B.
Photograph C shows the left ureter crossing the pelvic brim at the bifurcation of the common iliac artery. The ureter then descends into the pelvis to enter the bladder at the trigone.
Photograph A shows the posterior abdominal wall. The aorta is visible running over the anterior surface of the vertebral bodies and psoas muscle lies lateral to the vertebral column.
Photograph B shows a closer image of psoas and many small fibres can be seen piercing through the muscle – these are some of the nerves of the lumbar plexus. Lateral to psoas is quadratus lumborum which passes between the 12thrib and the iliac crest. Transversus abdominis can also be seen completing the lateral edge of the posterior abdominal wall.
Photograph C shows the distal part of psoas and the long pale tendon that lies on the surface of the muscle. This is called psoas minor in some texts, with the rest of the muscle described as psoas major. Both psoas major and minor act to flex the trunk and join with iliacus to form iliopsoas.
Photograph A shows iliacus attaching to the surface of the iliac fossa. It is supplied with motor innervation by the femoral nerve, and this is shown in photograph B.
Photograph A shows the posterior abdominal wall after removal of the viscera. The aorta and IVC lie slightly over to the left and right sides of the vertebral bodies respectively but cannot be seen clearly due to the covering of peritoneum.
Photograph B shows the inferior vena cava after removal of the peritoneum. The renal veins can be observed draining directly into the IVC, as can the right gonadal vein.
Photograph C shows some of the lumbar veins which drain the posterior abdominal wall. Lumbar veins from L3 and L4 levels usually drain directly into the IVC.
The anterior branches of the aorta have already been described during dissection of the foregut, midgut and hindgut. Some of the lateral branches such as the renal and suprarenal arteries have also already been described.
The gonadal arteries branch from the anterolateral surface of the abdominal aorta between the superior and inferior mesenteric arteries (around L2 vertebral level). The right gonadal artery is show in photograph A.
Photograph B shows a lateral view of the vertebral bodies with the abdominal aorta passing along their anterior surface. The aorta has been raised from the vertebral bodies to show the lumbar arteries that branch from the posterior surface of the aorta to supply the posterior abdominal wall.
Photograph C shows the pelvic brim. The aorta bifurcates at L4 vertebral level into the left and right common iliac arteries. These in turn divide into an internal and external iliac artery on each side, to supply the pelvis and the lower limb. The IVC is formed at vertebral level L5 when the two common iliac veins unite, bringing venous blood from the lower limbs and the pelvis into the IVC.
Photograph A shows psoas muscle as it passes from the lumbar vertebrae to join with iliacus. The roots of the lumbar plexus lie posterior to psoas and branches of the plexus pierce the muscle and lie on its anterior surface before passing towards the inguinal region, perineum and lower limb.
Photograph B shows some of the nerves of the lumbar plexus – note that these more superficial branches are thin, delicate nerves that cross laterally away from the vertebral bodies. The deeper branches of the plexus – the femoral, obturator and lumbosacral trunk nerves are more robust as they contain more nerve fibres. For example, the ilioinguinal nerve only has fibres from L1 vertebral level whereas the femoral nerve carries fibres from L2, L3 and L4 levels.
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Photograph A shows the surface of psoas muscle after removal of the peritoneum. It shows the first branches of the lumbar plexus, both from L1 vertebral level. The iliohypogastricand ilioinguinal nerves may emerge separately from the plexus to lie on the anterior surface of psoas (as shown here) or may form a common trunk before dividing into 2 as they pass through psoas. The ilioinguinal nerve passes through the posterior wall of the inguinal canal to emerge onto the skin via the superficial inguinal ring. Both nerves carry cutaneous fibres and both supply motor fibres to internal oblique and transversus abdominis.
Photograph B shows the genitofemoral nerve, it forms from L1 and L2 roots and passes down the anterior surface of psoas towards the inguinal region. This nerve divides into a femoral and genital branch. Photograph C shows the division close to the pelvis, thought the nerve may divide higher up in some individuals. The genital branch of the genitofemoral nerve passes through the deep inguinal ring to become part of the spermatic cord and supply cremaster muscle, the femoral branch passes towards the skin of the thigh.
Photograph A shows the lateral femoral cutaneous nerve – a branch of L2 and L3 roots. It crosses the anterior surface of iliacus as it passes to supply cutaneous innervation to the lateral side of the thigh.
To identify the roots of the lumbar plexus a deeper dissection is needed. Photograph B shows the roots following the removal of psoas. This must be performed carefully in a piecemeal fashion to ensure the nerves are preserved as the muscle fibres are gently teased away with forceps.
Photograph C shows a closer view of the roots of L1 to L4 – the anterior rami that contribute to the plexus. It also shows the origins of the smaller, more superficial branches described in the last 2 slides.
The final branches of the lumbar plexus are shown on this slide.
The femoral nerve is shown in photograph A. The femoral nerve is a relatively large, cord-like structure that arises from L2, L3 and L4 roots and then passes under the inguinal ligament to enter the femoral triangle and supply motor and sensory innervation to the anterior compartment of the thigh.
Photograph B shows the obturator nerve, which also arises from L2, L3 and L4 roots. It passes into the pelvis, around the inner surface of the lateral wall and through the obturator foramen to supply sensory and motor innervation to the medial compartment of the thigh.
Photograph C shows the lumbosacral trunk that carries L4 and L5 nerve fibres into the pelvis to join part of the sacral plexus. The sciatic nerve – a large nerve supplying the posterior compartment of the thigh has a nerve root value of L4 to S3.
