Module 14 : Abdominal Wall

Question 1

indications for abdominal wall ultrasound

Answer 1

• palpable mall
• surgical wound assessment
• trauma
• findings on other modalities

Question 2

scanning techniques

Answer 2

• high frequency linear transducer
• minimal pressure (standoff pad needed)
• no patient prep needed

Question 3

abdominal wall layers

Answer 3

• epidermis
• subcutaneous tissue
• muscle

Question 4

epidermis

Answer 4

• 1-4mm thick

- highly reflective appears echogenic

Question 5

subcutaneous layer

Answer 5

• fat
• variable thickness and echogenicity
• typically less echogenic than muscle

Question 6

factors that influence the echogenicty of fat

Answer 6

• water content

- increase water increase echogenicity

Question 7

muscle layer - anterior and lateral

Answer 7

• rectus abdominus
• linea alba
• arcuate line
• external oblique
• internal oblique
• transversus abdominus

Question 8

rectus abdominus

Answer 8

• paired midline MOST ANTERIOR
• originates at symphysis pubis and pubic crest and inserts into the diploid process
• separated by line alba in middle
• rectus sheath encloses the RA muscle formed by the aponeuroses of internal and external and transverses abdominus
• contains 3 tendinous insertions that attach rectus sheath anteriorly = localize hemtomas

Question 9

aponeuroses

Answer 9

• flat sheet of strong fibrous connective tissue that serve as tendons to attach muscle to fixed points

Question 10

linea alba

Answer 10

• fibrous band that extends from the diploid to symphysis pubis
• formed by aponeuroses of 3 lateral abdominal muscles
• wider above umbilicus
• echogenic
• creates refractive duplication artifact

Question 11

arcuate line

Answer 11

• point between umbilicus and symphysis pubis where posterior portion of rectus sheath passes in front of rectus muscle

Question 12

external oblique

Answer 12

• outer layer
• origin = outer surface of lower 8 ribs
• runs diagonally (outer jacket pocket)

Question 13

internal oblique

Answer 13

• lies deep to external oblique
• runs in diagonal fashion 90’ to external
• inner jacket pocket

Question 14

transversus abdominus

Answer 14

• deep to internal oblique
• run horizontal
• innermost

Question 15

sonographic appearance of muscle

Answer 15

• hypo echoic to sonolucent
• specular reflectors
• striated

Question 16

muscle layer - posterior wall

Answer 16

• psoas major
• quadratus lumborum
• iliacus

Question 17

psoas major

Answer 17

• fan shaped
• origin = sides of vertebral column
• inserts = lesser trochanters of femur
• appears hypo echoic and lateral to spine

Question 18

quadratus lumborum

Answer 18

• posterolateral to psoas
• flat muscle
• origin = iliac crest
• inserts = 12th rib and upper 4 lumbar vertebrae
• directly posterior to kidney

Question 19

iliacus

Answer 19

• origin = iliac fossa sacrum and SI joint

- inserts = psoas major and lesser trochanter

Question 20

inguinal canal

Answer 20

• obliquely oriented tunnel
  + runs inferior and medial
• slit like passage way
• opening at each end
  + deep intgional ring / internal
  + superficial inguinal ring / external
• contains spermatic cord and round ligament
• anterior wall formed by aponeurosis of external oblique
• posterior wall formed by transversalis fascia

Question 21

deep inguinal ring / internal

Answer 21

• opening at superior end of canal
• midway between anterior superior iliac spine ASIS and symphysis pubis
• defect in transversalis fascia

Question 22

superficial inguinal ring / external

Answer 22

• opening at inferior end of canal

- through external oblique aponeurosis

Question 23

diaphragm

Answer 23

• dome shaped partition separating the thorax from abdominal cavity
• muscle and tendon
• major active muscle of respiration
• originates at periphery of thoracic cage with 3 groupf of muscle fibre
  + lumbar spine (crura)
  - right = broader and longer
  - join in midline to form arcuate ligament
  + lower sternum
  + lower 6 ribds
• 3 groups coverage radially and insert into central tendon

Question 24

diaphragm on ultrasound

Answer 24

• highly echogenic arc

Question 25

crura on ultrasound

Answer 25

- thin hypo echoic band - superior to celiac axis - anterior to aorta - at celiac axis lateral to aorta - poster to IVC

Question 26

2 scanning approaches to assess pleural space

Answer 26

- abdominal approach (subcostal) | - intercostal

Question 27

2 windows used when scanning inferior aspect of pleural space - abdominal approach

Answer 27

- liver | - spleen

Question 28

normal thickness of diaphragm

Answer 28

- 5 mm

Question 29

mirror image artifact

Answer 29

- evidence of absence of pleural effusion | + if no reflection then fluid in pleural space

Question 30

distance of pleural space to rib interface - intercostal

Answer 30

- pleural space within 1 cm from rib interface

Question 31

visceral pleura ultrasound

Answer 31

- on the lungs - bright linear interface - moves with respiration

Question 32

parietal pleura ultrasound

Answer 32

- weak echogenic line or obscured | - hypo echoic separation of parietal and visceral pleural

Question 33

gliding sign

Answer 33

- visceral pleura moving with long during respiration