9. Lumbosacral plexus and kidneys

Question 1

network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb. It is located on the surface of the posterior pelvic wall, anterior to the piriformis muscle.

Answer 1

sacral plexus

Question 2

the sacral pelxus is formed by

Answer 2

anterior rami (divisions) of the sacral spinal nerves S1, S2, S3 and S4.

It also receives contributions from the lumbar spinal nerves L4 and L5.

Question 3

peripheral nerves of sacral plexus

Answer 3

5 major

Some Irish Sailor Pesters Polly’.

1. Superior Gluteal Nerve 2. Inferior Gluteal Nerve
2. Sciatic Nerve
3. Posterior Femoral Cutaneous
4. Pudendal Nerve

other branches

Nerve to piriformis
Nerve to obturator internus
Nerve to quadratus femoris

Question 4

2 main destinations the nerves of sacral plexus

Answer 4

• Leave the pelvis via the greater sciatic foramen -> gluteal region
• Remain in the pelvis

Question 5

this nerve leaves the pelvis via the greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle. It is accompanied by the superior gluteal artery and vein for much of its course.

Answer 5

superior gluteal nerve

Question 6

roots of superior gluteal nerve

Answer 6

L4,L5, S1

Question 7

Roots of inferior gluteal nerve

Answer 7

L5,S1,S2

Question 8

Roots of sciatic nerve

Answer 8

L4,L5,S1,S2,S3

Question 9

roots of posterior femoral cutaneous

Answer 9

S1,S2,S3

Question 10

roots of pundendal nerve

Answer 10

S2,S3,S4

Question 11

fx of superior gluteal nerve

Answer 11

Motor Functions: Innervates the gluteus minimus, gluteus medius and tensor fascia lata.

Sensory Functions: None.

Question 12

fx of inferior gluteal nerve

Answer 12

Motor Functions: Innervates gluteus maximus.

Sensory Functions: None.

Question 13

roots of sciatic nerv

Answer 13

L4, L5, S1, S2, S3

Question 14

motor fx of sciatic nerve

Answer 14

Tibial portion – Innervates the muscles in the posterior compartment of the thigh (apart from the short head of the biceps femoris), and the hamstring component of adductor magnus. Innervates all the muscles in the posterior compartment of the leg and sole of the foot.

Common fibular portion – Short head of biceps femoris, all muscles in the anterior and lateral compartments of the leg and extensor digitorum brevis.

Question 15

sensory fx of sciatic nerve

Answer 15

Tibial portion: supplies the skin of the posterolateral leg, lateral foot and the sole of the foot.
Common fibular portion: supplies the skin of the lateral leg and the dorsum of the foot.

Question 16

leaves the pelvis via the greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle. It descends deep to the gluteus maximus and runs down the back of the thigh to the knee.

Answer 16

Posterior Femoral Cutaneous

Question 17

fx of Posterior Femoral Cutaneous

Answer 17

Motor Functions: None

Sensory Functions: Innervates the skin on the posterior surface of the thigh and leg. Also innervates the skin of the perineum.

Question 18

This nerve leaves the pelvis via the greater sciatic foramen, then re-enters via the lesser sciatic foramen. It moves anterosuperiorly along the lateral wall of the ischiorectal fossa, and terminates by dividing into several branches.

Answer 18

Pudendal Nerve

Question 19

fx of pudendal nerve

Answer 19

Motor Functions: Innervates the skeletal muscles in the perineum, the external urethral sphincter, the external anal sphincter, levator ani.

Sensory Functions: Innervates the penis and the clitoris and most of the skin of the perineum.

Question 20

intramuscular injection into the gluteal region must be given in the

Answer 20

upper lateral quadrant to avoid sciatic nerve (which passess through the lower media quadrant )

Question 21

refers to compression of the sciatic nerve by the piriformis muscle.

Answer 21

Piriformis syndrome/ deep gluteal syndrome

Question 22

Clinical features include radicular pain, numbness, muscle weakness and buttock tenderness. The pain can occasionally be exacerbated by internal rotation of the lower limb at the hip.

Answer 22

Piriformis syndrome

Question 23

Lab findings of piriformis syndrome

Answer 23

X-ray and MRI imaging is usually unremarkable but can exclude other pathology such as spinal compression of the sciatic nerve.

Question 24

The treatment of piriformis syndrome can be divided into non-operative and operative:

Answer 24

Non-operative – analgesia, physiotherapy and corticosteroid injections
Operative – piriformis muscle release

Question 25

bilateral bean-shaped organs, reddish-brown in colour and located in the posterior abdomen.

Answer 25

Kidneys

Question 26

main fx of kidneys

Answer 26

filter and excrete waste products from the blood. They are also responsible for water and electrolyte balance in the body.

Question 27

level of kidneys

Answer 27

T12-L3 | right kidney is slightly lower due to the presence of the liver

Question 28

Kidney is covered | deep to superficial

Answer 28

renal capsule perirenal fat fenal fascia / Gerota’s fascia Pararenal fat

Question 29

the renal parenchyma are divided into

Answer 29

cortex | medulla

Question 30

The cortex extends into the medulla, dividing it into triangular shapes – these are known as

Answer 30

renal pyramids

Question 31

The apex of a renal pyramid is called a

Answer 31

renal papilla

Question 32

Each renal papilla is associated with a structure known as the____, which collects urine from the pyramids

Answer 32

minor calyx

Question 33

encloses the kidneys and the suprarenal glands.

Answer 33

renal fascia

Question 34

Several minor calices merge to form a

Answer 34

major calyx

Question 35

Urine passes through the major calices into the

Answer 35

renal pelvis

Question 36

The medial margin of each kidney is marked by a deep fissure, known as the

Answer 36

renal hilum

Question 37

The kidneys are supplied with blood via the

Answer 37

renal arteries

Question 38

this renal artery is longer, and crosses the vena cava posteriorly.

Answer 38

Due to the anatomical position of the abdominal aorta (slightly to the left of the midline), the right renal artery is longer

Question 39

carry 75% of blood supply to the kidney

Answer 39

anterior division of the renal artery

Question 40

25% of the blood supply to the kidney

Answer 40

posterior division of the renal artery

Question 41

avascular plane of the kidney | aka

Answer 41

line of brodel

Question 42

is an imaginary line along the lateral and slightly posterior border of the kidney, which delineates the segments of the kidney supplied by the anterior and posterior divisions.

Answer 42

avascular plane of the kidney (line of Brodel)

Question 43

It is an important access route for both open and endoscopic surgical access of the kidney, as it minimises the risk of damage to major arterial branches.

Answer 43

avascular plane of the kidney (line of Brodel)

Question 44

Each segmental artery divides to form

Answer 44

interlobar arteries

Question 45

urine flow from renal papilla to bladder

Answer 45

renal papilla -> minor calyx -> major calyx ->major calyx -> renal pelvis -> ureter -> bladder

Question 46

This acts as a gateway to the kidney – normally the renal vessels and ureter enter/exit the kidney via this structure.

Answer 46

renal hilum

Question 47

segmental artery to efferent arterioles

Answer 47

segmental artery -> interlobar arteries -> arcuate arteris -> interlobular arteries -> afferent arterioles (cortex) - form glomerulus -> efferent arterioles

Question 48

a At 90 degrees to the arcuate arteries, these arteries arise

Answer 48

interlobular arteries

Question 49

supplies the nephron tubules with oxygen and nutrients.

Answer 49

peritubular network

Question 50

peritubular network is formed by

Answer 50

efferent arterioles in the outer 2/3 of the renal cortex

Question 51

The inner third of the cortex and the medulla are supplied by

Answer 51

long, straight arteries called vasa recta.

Question 52

accessory arteries of the kidneys are common in ___ % of patients

Answer 52

25%

Question 53

If a supernumerary artery does not enter the kidney through the hilum, it is called

Answer 53

aberrant

Question 54

venous drainage of the kidneys

Answer 54

left and right renal veins.

Question 55

left and right renal veins drain into

Answer 55

IVC

Question 56

this renal vein is longer

Answer 56

As the vena cava lies slightly to the right, the left renal vein is longer

Question 57

this renal artery lies posterior to the inferior vena cava.

Answer 57

right renal artery

Question 58

Lymph from the kidney drains into the

Answer 58

lateral aortic (or para-aortic) lymph nodes

Question 59

In utero, the kidneys develop in the pelvic region and ascend to the lumbar retroperitoneal area. Occasionally, one of the kidneys can fail to ascend and remains in the pelvis – usually at the level of the

Answer 59

common iliac artery

Question 60

failure of kidneys to ascend in utero

Answer 60

pelvic kidney

Question 61

is where the two developing kidneys fuse into a single horseshoe-shaped structure.

Answer 61

horseshoe kidney (also known as a cake kidney or fused kidney)

Question 62

This occurs if the kidneys become too close together during their ascent and rotation from the pelvis to the abdomen – they become fused at their lower poles (the isthmus) and consequently become ‘stuck’ underneath this artery

Answer 62

inferior mesenteric artery

Question 63

Horseshoe kidney presentation

Answer 63

asymptomatic, although it can be prone to obstruction

Question 64

most common tumor of the kidneys

Answer 64

renal cell carcinoma

Question 65

kidneys is closely in contact with this muscle

Answer 65

psoas major

Question 66

3 structures that enter/ leave at renal hilum

Answer 66

1. renal vein - anterior 2. renal artery 3. renal pelvis - posterior

Question 67

T/F | fibrous capsule of the kidneys is a true capsule

Answer 67

true

Question 68

Gerota’s fascia is continuous laterally with

Answer 68

fascia tranversalis

Question 69

how many renal pyramids

Answer 69

12 pyramids

Question 70

nerve supply of kidneys

Answer 70

renal sympathetic plexus | T10-12

Question 71

renal transplantation | usual site

Answer 71

iliac fossa on the posterior abdominal wall

Question 72

for renal transplantation, renal artery is anastomosed to

Answer 72

internal iliac artery

Question 73

for renal transplantation, renal vein is anastomosed to

Answer 73

external iliac vein

Question 74

rare vein compression disorder. It occurs when arteries, most often the abdomen’s aorta and superior mesenteric artery, squeeze the left renal (kidney) vein.

Answer 74

nutcracker syndrome

Question 75

if left renal vein is compressed by SMA as the vein crosses anterior to the aorta this results

Answer 75

renal and adrenal hypertension on the Left in males: varicocele on the left