91 - Posterior Abdominal Wall

Question 1

*Layout of posterior abdominal wall

Answer 1

Question 2

Proportion of people who have a psoas minor

Answer 2

~2/3

Question 3

Muscle inferolateral to psoas major

Answer 3

Iliacus muscle

Question 4

Muscle posteromedial to psoas

Answer 4

Anterior abdominal muscles

Question 5

Psoas major location

Answer 5

In paravertebral gutter

Question 6

Shape of psoas lateral border

Answer 6

A straight, oblique line

Question 7

Origin of psoas major

Answer 7

One continuous origin along the spine. From T12 to L5. Attaches to vertebral bodies, IV discs, medial edges of transverse processes

Question 8

Psoas major function

Answer 8

Flexor of the vertebral column

Question 9

Where is the lumbar plexus located?

Answer 9

Within psoas major

Question 10

Where does psoas major attach to?

Answer 10

Lesser trochanter of femur

Question 11

Location of vessels and nerves, relative to psoas major

Answer 11

Lumbar plexus is within psoas major. Vessels are behind. Sympathetic trunk is in front.

Question 12

Psoas minor

Answer 12

Phylogenetically degenerating muscle. In about 2/3 of people overlies psoas major. Doesn’t enter inguinal canal.

Question 13

Quadratus lumborum attachment

Answer 13

Attaches between T12 and Iliac crest. Attaches to the transverse processes between these.

Question 14

Function of quadratus lumborum

Answer 14

Stabilises the 12th rib, and acts as a flexor

Question 15

Iliacus muscle shape

Answer 15

Inverted triangle

Question 16

Iliacus muscle origin

Answer 16

Iliac crest

Question 17

Iliacus muscle attachment

Answer 17

Attaches to lesser trochanter of the femur

Question 18

Muscles with a common insertion into the lesser trochanter

Answer 18

Iliacus and psoas major

Question 19

Iliopsoas

Answer 19

Conjoined tendon of iliacus and psoas major, inserting into the lesser trochanter of the femur

Question 20

Arrangement of fascia of the posterior abdominal wall

Answer 20

All muscles have their own fascia, except for quadratus lumoborum and erector spinae. Erector spinae and quadratus lumborum are enclosed in thoracolumbar fascia.

Question 21

Thoracolumbar fascia attachments

Answer 21

One layer behind tips of spinous processes. Middle layer attaches to transverse processes. Most anterior layer attaches to the front of transverse processes.

Question 22

Thoracolumbar fascia structure

Answer 22

Trilaminar

Question 23

Where do all the layers of the thoracolumbar fascia fuse?

Answer 23

Along line of the 12th rib

Question 24

Muscles enclosed by thoracolumbar fascia

Answer 24

Quadratus lumborum and erector spinae

Question 25

How are quadratus lumborum enclosed in thoracolumbar fascia?

Answer 25

In anterior compartment

Question 26

Where on the posterior abdominal wall do the internal obliques and transversus abdominis attach?

Answer 26

Lateral edge of thoracolumbar fascia.

Question 27

Why don’t the external obliques attach to the thoracolumbar fascia?

Answer 27

Lats intervene.

Question 28

How can a psoas abscess arise?

Answer 28

TB osteomyelitis can lead to an eruption of the psoas.

Question 29

Are kidneys intra- or retro-peritoneal?

Answer 29

Retroperitoneal

Question 30

Where in the body do the kidneys sit?

Answer 30

In the paravertebral gutters. Almost posterior to spine. Overlie quadratus lumborum.

Question 31

Relative positions of kidneys to one another.

Answer 31

Right sits a bit lower than the left because of the liver superiorly.

Question 32

Why do the kidneys move on inspiration?

Answer 32

Associated with the diaphragm

Question 33

Size of kidneys

Answer 33

10cm long 5cm wide 2.5cm thick

Question 34

Shape of adrenal glands.

Answer 34

Asymmetrical. Party hat shape on the right kidney. Crescent shape on the left kidney.

Question 35

Broad divisions of kidneys

Answer 35

Outer cortex - Continuous band of pale tissue Inner medulla - Discontinuous, dark, pyramids

Question 36

Broad divisions of kidneys

Answer 36

Outer cortex - Continuous band of pale tissue Inner medulla - Discontinuous, dark, pyramids

Question 37

What surrounds the kidneys?

Answer 37

Fibrous capsule, fat, renal fascia

Question 38

Which direction do the renal hila face?

Answer 38

Antero-medially

Question 39

Anterior to posterior structures inserting into the kidney hila

Answer 39

Vein, artery, duct

Question 40

Cavity within kindey

Answer 40

Renal sinus

Question 41

What fills renal sinus

Answer 41

Fat

Question 42

Structures embedded in fat within the renal sinus

Answer 42

Vein, artery, ureteric pelvis

Question 43

Structure of main renal artery

Answer 43

One enters hilum, splits into five segmental arteries.

Question 44

Effect of kidney position change during development

Answer 44

Loses lower blood supply, gains upper blood supply. In ~25% of people can see accessory renal artery, which has persisted.

Question 45

Which vessel do the renal veins join to?

Answer 45

IVC

Question 46

Where do the renal arteries arise from?

Answer 46

Abdominal aorta

Question 47

Path of the right renal vein relative to aorta

Answer 47

Passes anterior to aorta

Question 48

Structure of ureteric/renal pelvis

Answer 48

Two-three major calyces. Each of these collect from two or three minor calyces. Minor calyces each receive apex of renal pyramids.

Question 49

Length of ureters

Answer 49

25-30cm

Question 50

Most superior part of ureters

Answer 50

Ureteric pelvis

Question 51

Path of ureters

Answer 51

Descend on anterior face of psoas major. Run along lateral wall of pelvis. Enter bladder obliquely

Question 52

Ureter blood supply

Answer 52

Take blood supply from whatever they’re passing

Question 53

Areas of narrowing of ureters where kidney stones can lodge 1 2 3

Answer 53

1) Ureteropelvic junction 2) Crossing of iliac artery (mid-ureter) 3) Ureto-vesicular junction (where inserts into bladder)