Module 14 : Abdominal Wall Flashcards
indications for abdominal wall ultrasound
- palpable mall
- surgical wound assessment
- trauma
- findings on other modalities
scanning techniques
- high frequency linear transducer
- minimal pressure (standoff pad needed)
- no patient prep needed
abdominal wall layers
- epidermis
- subcutaneous tissue
- muscle
epidermis
- 1-4mm thick
- highly reflective appears echogenic
subcutaneous layer
- fat
- variable thickness and echogenicity
- typically less echogenic than muscle
factors that influence the echogenicty of fat
- water content
- increase water increase echogenicity
muscle layer - anterior and lateral
- rectus abdominus
- linea alba
- arcuate line
- external oblique
- internal oblique
- transversus abdominus
rectus abdominus
- 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
aponeuroses
- flat sheet of strong fibrous connective tissue that serve as tendons to attach muscle to fixed points
linea alba
- 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
arcuate line
- point between umbilicus and symphysis pubis where posterior portion of rectus sheath passes in front of rectus muscle
external oblique
- outer layer
- origin = outer surface of lower 8 ribs
- runs diagonally (outer jacket pocket)
internal oblique
- lies deep to external oblique
- runs in diagonal fashion 90’ to external
- inner jacket pocket
transversus abdominus
- deep to internal oblique
- run horizontal
- innermost
sonographic appearance of muscle
- hypo echoic to sonolucent
- specular reflectors
- striated
muscle layer - posterior wall
- psoas major
- quadratus lumborum
- iliacus
psoas major
- fan shaped
- origin = sides of vertebral column
- inserts = lesser trochanters of femur
- appears hypo echoic and lateral to spine
quadratus lumborum
- posterolateral to psoas
- flat muscle
- origin = iliac crest
- inserts = 12th rib and upper 4 lumbar vertebrae
- directly posterior to kidney
iliacus
- origin = iliac fossa sacrum and SI joint
- inserts = psoas major and lesser trochanter
inguinal canal
- 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
deep inguinal ring / internal
- opening at superior end of canal
- midway between anterior superior iliac spine ASIS and symphysis pubis
- defect in transversalis fascia
superficial inguinal ring / external
- opening at inferior end of canal
- through external oblique aponeurosis
diaphragm
- 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
diaphragm on ultrasound
- highly echogenic arc
crura on ultrasound
- thin hypo echoic band
- superior to celiac axis - anterior to aorta
- at celiac axis lateral to aorta
- poster to IVC
2 scanning approaches to assess pleural space
- abdominal approach (subcostal)
- intercostal
2 windows used when scanning inferior aspect of pleural space - abdominal approach
- liver
- spleen
normal thickness of diaphragm
- 5 mm
mirror image artifact
- evidence of absence of pleural effusion
+ if no reflection then fluid in pleural space
distance of pleural space to rib interface - intercostal
- pleural space within 1 cm from rib interface
visceral pleura ultrasound
- on the lungs
- bright linear interface
- moves with respiration
parietal pleura ultrasound
- weak echogenic line or obscured
- hypo echoic separation of parietal and visceral pleural
gliding sign
- visceral pleura moving with long during respiration
