C13: Abdominal Wall Flashcards
what are some indications for an Abdo wall US?
- palpable mass (from abdo, or wall?)
- surgical wound assessment
- trauma
- findins on other DI tests
+ us a high frequency probe
what is a standoff pad? why is it used
- gel like pad to increase the distance b/w the probe and the abdo wall…
- used to minimize the main bang artifact
what are the 3 layers of the abdo wall
- epidermis
- subcutaneous tissue (fat)
- muscle
how does the epidermis appear on US and how thick should it be
- echogenic
- 1-4 mm thick
how does the subcutaneous tissue (fat) appear on US and how thick should it be
- variable thickness
- variable echogenicity but usually less echogenic than muscle
what factor influences the echogencity of fat
water content…. more water makes it appear more echogenic because water and fat dont mix so you end up with multiple interfaces which appear bright
describe the rectus abdominis (RA).
where is it located? where does it originate and where does it insert
- paired, located midline and anterior on the abdo wall (most anterior muscles of the abdo)
- separated by the lines alba
- originates at pubic symphysis and pubic crest and inserts into the xiphoid process and costal cartilage
what is the rectus sheath?
what is it made out of
- sheath that encloses the RA muscles
- formed by the aponeuroses of the internal, external and transverse abdominus
where do the 3 tendinous insertions of the RA muscle attach?
what is there function
- to the rectus sheath anteriorly… b/w the xiphoid and inferior to the umbilicus
- allow for localization of hematomas
what is an aponeuroses?
-flat sheet of fibrous c-tissue that serves as a tendon to attach muscle to fixed points
describe the line alba
what forms this structure?
what artifact does it commonly cause
- fibrous band that extends from the xiphoid to the pubic symphysis
- wider above the belly button and appear echogenic on US
+formed by the aponeuroses of the 3 lateral abdo muscles
-refractive duplication artifact
what is the arcuate line
- a point b/w the umbilicus and the pubic symphysis where the posterior part of the rectus sheath passes in front of the rectus muscle….
… now theres only c-tissue located anteriorly
describe the external oblique muscles, where do they originate and insert.
how do they run?
- outer layer of muscle on the anterolateral abdo wall
- originate from the outer surface of the lower 8 ribs
- run diagonally and insert into the xiphoid, linea alba, pubic bones and anterior iliac crest
describe the internal oblique muscles, where do they originate and insert.
how do they run?
- deep to the external obliques… run 90 degrees to the externals
- originate from the lumbar fascia, anterior iliac crest and inguinal ligament
- insert into the lower 3 ribs, xiphoid, linea alba and pubic symphysis
describe the tranversus abdominis muscles, where do they originate and insert.
how do they run?
- deep to the internal obliques…. run horizontally
- originate from the lower 6 ribs, lumbar fascia, iliac crest and inguinal ligament
- insert into the xiphoid, linea alba and pubic symphysis
whats the US appearance of muscle tissue
- hypoechoic to sonolucent (anechoic)
- specular reflectors
- striated appearance in SAG…. speckled in TRX
what are the 3 muscles of the posterior abdo wall
- Psoas major
- Quadratus lumborum
- iliacus
describe the psoas major muscles, where do they originate and insert.
how do they appear on US?
- fan shaped muscles
- originate from the side walls of the vertebral column
- insert into the lesser trochanters of the femurs
- look hypoechoic
describe the quadratus lumborum muscles, where do they originate and insert.
- posterolateral to the psoas muscles and directly posterior to the kidneys… flat muscle
- originate at the iliac crest
- insert into the 12th rib and upper4 lumbar vertebra
where do the iliacus muscles originate and insert?
-originate at the iliac fossa, sacrum and SI joints
what is the inguinal canal?
how does it run in the body
-a slit like passage way thats obliquely oriented tunnel that runs inferior and medial in the body
what are the 2 openings of the inguinal canal and where are they located
- Deep inguinal ring/internal ring
- opening at the superior end of the canal
- located b/w the anterior superior iliac spine and pubic symphysis
- Superficial inguinal ring/external ring
- opening at the inferior end of the canal that goes through the external oblique aponeurosis
which opening of the inguinal canal is a defect of the transversalis fascia?
deep inguinal ring
the inguinal canal contains which structures and its walls are formed by which structures?
-contain spermatic cord (M) and round ligament (W)
Anterior wall:
-formed by aponeuroses of external obliques
Posterior wall:
- formed by transversalis fascia
describe the diaphragm… what is it made of
- dome shaped partition separating the thorax from the abdo
- made of muscle and tendon… active muscle of respiration
where does the diaphragm originate
at the periphery of the thoracic cage w/ 3 groups of muscle fibres….
- lumbar spine (crura)
- lower sternum
- lower 6 ribs
what structure joins midline to form the arcuate line
lumbar spine/crura
which crus of the diaphragm is longer and broader
R
where do the 3 muscles fibres of the diaphragm insert and what do they form
-insert radially and from a central tendon
describe the relationship of the crura to the celiac axis and IVC
- above the level of the celiac axis its anterior to the AO…at the celiac axis its lateral to the AO
- posterior to IVC
SEE questions 1-7 about the pleural space
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