abdominal wall 1 Flashcards
what are the quadrants of the abdomen?
- trans umbilical plane (L3/4)
- midline
- this creates 4 quadrants (right and left upper and lower)
how are the surface regions split for neonates?
- midclavicular lines
- subcostal plane (L3)
- intertubercular line (iliac crest tubercles) -L5
This creates:
- the right and left hypochindrium, flank and groin
- midline- epigastric, umbilical and pubic region.
what are the layers of the abdomen from superficial to deep?
- skin
- superficial fascia: (camper’s fascia (fatty) and scarpa’s fascia (membranous)
- muscular layers: (with investing fascia) (external oblique, internal oblique, transversus abdominis)
- transversalis fascia
- extraperitoneal fascia
- parietal peritoneum
what will Camper’s and Scarpa’as fascia be continous with?
it continous into the perineum
how would you describe the structure of the skin?
why do we cut parralel to these lines?
the skin has Langers lines on it:
- we ideally cut parallel to the lines otherwise tension will occur across the incision and lead to a larger scar
what are the 3 flat muscles of the abdominal wall?
- external oblique
- internal oblique
- transversus abdominalis
what is the one straight muscle?
rectus abdominis
what is the small inconsistent muscle of the abdomen?
pyramidalis
what is the function of the abdominla wall muscles?
- supports anterolateral abdominal wall
- supports and protects the abdominal viscera
- maintains and raises the intraabdominal structures (antagonise diaphragmatic action, forced expiration)
- flexes and roated the trunk
- aids posture
describe the innervation of the abdominal wall muscles?
supplied by 3 different nerves:
- thoracoabdominal nerves (anterior rami of T6-11)
- subcostal nerve (T12)
- iliohypogastric (L1)
rectus abdominis:
- attachments
- innervation?
- function?
attachments:
- from pubic crest, symphyis, tubercle to costal cartillages of rivs 5,6,7 and xiphoid process
innervation:
- anterior rami of T6-T12
function:
- flexes the trunk, compresses viscera, stabilises the pelvis (resists anterior tilt)
Has 6 tendinous intersections (6 pack)
within the rectus sheath
pyramidalis:
- attachments?
- function?
- innervation?
this muscle is only found in 70% of people
attachments:
- pubic crest to linea alba
function:
- tenses linea alba
innervation:
- anterior rami of T12
what forms the abdominal wall rectus sheath?
what do they all unite to form?
formed from aponeuroses of:
- external oblique
- internal oblique
- tranversus abdominis
- tranversalis fascia
- They unite centrally to form linea alba from pubic sympysis to xiphoid process
what happens to the abdominal wall rectus sheath above the arcuate line?
and below the arcuate line?
- above the arcuate line, internal oblique aponeurosis splits to cover rectus abdominis anteriorly and posterirly.
- below the arcuate line, aponeuroses are anterior to rectus abdominis
what is contained within the rectus sheath?
- abdominis
- pyramidalis
- superior and inferior epigastric vessels.
inguinal ligament:
- where is it?
- attachments?
- where does its fibres insert?
- what does these insertions create?
- it is at the lower border of the external oblique aponeurosis
- attaches to the ASIS to the pubi tubercle
- some fibres insert on pecten pubis, forming the lacunar ligament
Lacunar Ligament?
- what are its posterior extension called?
this is the medial border of the femoral triangle
- it has a posterior extension along pectineal line termed pectineal ligament
describe the thoraco- lumbar fascia?
where is the weak spot?
- this is tough strong fascia in the lumbar region
- there is a weak spot between lat dorsi and external oblique, this is called the Triangle of Petit (inferior lumbar triangle)… a lumbar hernia can occur here.
where does the thoracolumbar fascia insert onto?
inserts onto the iliac crest, lumbar vertebra and ribs.
what 2 muscles will insert into the thoraco lumbar fascia?
internal oblique and transversus abdominalis.
internal oblique:
- innervation?
Innervation:
- T6-L1 anterior rami
transversus abdominis:
innervation?
innervation:
- T6-L1 anterior rami
what 2 thing will the conjoint tendon connect?
what is anterior to it?
AKA - inguinal Flax
the internal oblique and transversus abdominis share an insertion on the pubic crest and pectineal line via the conjoint tendon.
- the superficial inguinal ligament ring opens anteriorly
what will pass through the inguinal canal fro males and females?
what is the inguinal canal?
This is a passage within the inferior aspect of the anterior abdominal wall and it allows structures to pass from the abdominal cavity externally.
male = spermatic cord
female = round ligament of the uterus
both= genital branch of genitofemoral nerve L1, 2 and ilioinguinal nerve L1.
has a deep and superficial ring
what is Processus Vaginalis?
this is an outpuching of the peritoneum that proceeds testes descent, it should then close.
Failure to close = increased risk of indirect inguinal hernia.
what happens as the devloping testes descend through the inguinal canal?
it picks up layers of the abdominal wall, which become equivelant structures in the spermatic cord
where is the opening of the superficial ring of the inguinal canal?
what will reinforce the opening posterioly?
- the triangular opening is in the external oblique aponeurosis
- the conjoint tendon will reinforce the opening posteriorly.
the inguinal canal also has a deep ring, where is it?
- in the lateral inguinal fossa.
- this is lateral to the lateral umbilical cord.
it is an evagination of the transversalis fascia
what is an abdominal hernia?
a protusion of an organ through the wall of the body cavity
can be:
- incisional
- epigastric
- umbilical
- inguinal (3/4 are inguinal)
- femoral
where is a direct inguinal hernia likely to occur?
boundries of triangle
in the Inguinal Hesselbach’s trinagle:
- lateral = inferior epigasstric vessels
- medial = rectus abdomins
- inferior = inguinal ligament
Likely to occur if there is weakness in the anterior abdominal wall.
what are direct inguinal hernias?
small bowel/fat protusion that is covered by peritoneum and transversalis fascia.
- runs alongside the spermatic cord
- may enter the scrotum but this is not common
what are indirect inguinal hernias?
these ones will enter through the deep inguinal ring via persistent processus vaginalis
- the contents are covered by layers of spermatic cord
- LIKELY to enter the scrotum
what is a rectus sheath haematoma?
- bleeding into the rectus sheath, happens post trauma usually.
- epigastric vessels or muscles are damaged
- can be managed conservatively.
what is the layer of fascia that is directly superficial to the extraperitoneal fascia?
transversalis fascia
in a patient with a hernia at the T8 dermatome with no history of surgery, what type of hernia is likely to be present?
epigastric
give a summary of hernias?
- they usually present with a lump
- often increase in size on coughing or straining
- they reduce in size or disappear when relaxed or supine
- irreducible but non obstructed hernias may cause litle pain
- if a hernia causes obstruction, it will be tense tender and irredcable. (colicky abdominal pain, distension and vomitting may occur.)
- if trangulation occurs the lump will become red and tender
What are the boundaries of the Inguinal canal?
Posterior
Anterior
Roof
Floor
