Trunk wall II Flashcards
diaphragm: features
- seals inferior thoracic aperture
- post attachment more inferior than ant (coz of angulation of aperture)
- R dome high than L
- muscle fibres arise radially, converge to central tendon
- diaphragm contracts, height of dome decreases, increase volume of thorax
- pericardium attached to middle part of central tendon
diaphragm: list all attachments
- xiphoid
- costal margin of thoracic wall
- rib 11-12 ends
- ligaments across post ab wall
- lumbar vertebra
diaphragm: post attachment
- crura: anchors to anterolateral surface of vertebral column
- L3 (R), L2 (L)
arcuate ligs:
- median arcuate lig (btw crura)
- medial arcuate lig (TP L1)
- lateral arcuate lig (rib 12)
diaphragm: openings
inf vena cava:
- in central tendon
oesophagus:
- muscular part
aorta:
- posteriorly
respiration: general features
- pressure difference btw lungs + atmosphere
inhalation (inspiration): decrease alveolar pressure (increase lung size, contract diaphragm, elevation/outward of ribcage, intercostals)
exhalation (expiration): opposition, increase alveolar pressure
respiration: accessory muscles of inspiration
- sternocleidomastoid
- scalene
- pec minor
respiration: role of abdomen in inspiration
- relaxes
- accomodate expansion of thoracic cavity
- inferior displacement of abdominal viscera during diaphragm contraction
respiration: role of abdomen in expiration
- contracts
- assist in elevating domes of diaphragm
- reduce thoracic volume
Valsalva manoeuvre:
- contraction of ab muscles increase intra-abdominal pressure when diaphragm is in a fixed position
abdominal wall: consists of
- skin
- superficial (subcutaneous) fascia
- muscles
- deep fascia
- extraperitoneal fascia
- parietal fascia
abdominal wall: skeletal elements
- 5 lumbar vertebra + IV discs
- superior parts of pelvis
- inferior parts of thoracic cage
abdominal wall: muscle elements parts
- posterior
- lateral
- anterior
abdominal wall: post muscle elements
- lateral to vertebral column
- quadratus lumborum
- psoas major
- iliacus
abdominal wall: lateral muscle elements
- transverse abdominus
- internal oblique
- external oblique
abdominal wall: anterior muscle elements
rectus abdominus
what continues btw posterior, lateral and anterior parts of ab wall:
- fascia posteriorly
- aponeurosis from muscles in lateral wall
anterior abdominal wall: features
flat muscles, posterolateral -> replaced by aponeurosis towards midline
- external oblique
- internal oblique
- transversus abdominus
vertical muscles near midline -> enclosed in tendinous sheath from aponeurosis of flat muscles
- rectus abdominus
- pyramidalis
external oblique: sup attach
- muscular slips from outer surfaces rib 5-12
external oblique: inf attach
- lateral lip of iliac crest
- aponeurosis ending in linea alba (midline raphe)
external oblique: innervation
anterior rami of lower 6 thoracic spinal nerves (T7-T12)
external oblique: action
- compress abdominal contents
- flex trunk together
- each ipsilateral bend -> turning ant part of abdomen to opposite side
internal oblique: sup attach
- thoracolumbar fascia
- iliac crest
- inguinal lig (lateral 2/3)
internal oblique: inf attach
- lower 3/4 ribs
- aponeurosis ending in linea alba/ pubic line/ pectineal line
internal oblique: innervation
- anterior rami of lower 6 thoracic spinal nerves (T7-T12)
internal oblique: action
compress ab contents
- flex trunk together
- each mm bends trunk to same side, turning ant part of abdomen to same side
transversus abdominis: sup attach
- thoracolumbar fascia
- iliac crest
- inguinal lig (medial 1/3)
- costal cartilage of lower 6 ribs
transversus abdominis: inf attach
aponeurosis ending in linea alba/ pubic crest/ pectineal line
transversus abdominis: innervation
anterior rami of lower 6 thoracic spinal nerves (T7-T12)
transversus abdominis: action
compress abdominal contents
rectus abdominis: sup attach
costal cartilages of ribs 5-7
- xiphoid process
rectus abdominis: inf attach
- pubic crest
- pubic tubercle
- pubic symphysis
rectus abdominis: innervation
T7-T12
rectus abdominis: action
flexes vertebral column
- compress abdominal content
pyramidalis: sup attach
linea alba
pyramidalis: inf attach
anterior pubis and pubic symphysis
pyramidalis: innervation
T7-T12
pyramidalis: action
tenses linea alba
rectus sheath: features
- encloses rectus abdominis + pyramidalis
- layering of aponeuroses of EO/ IO/ TA
- encloses 3/4 of RA
- covers ant surface of lower 1/4
- post surface of lower 1/4 direct contact w transversalis fascia
rectus sheath: upper 3/4
anterior wall: aponeurosis of
- external oblique
- 1/2 internal oblique (splits at lateral margin of rectus abdominis)
posterior wall: aponeurosis of
- other 1/2 internal oblique
- transversus abdominis
rectus sheath: lower 1/4
- midway btw umbilicus and pubic symphysis: all aponeuroses anterior to rectus muscle (arcuate line)
- no post sheath
- ant sheath: EO/ IO/ TA
- rectus abdominis direct contact with transversalis fascia
inguinal region: features
- junction btw abdomen and thigh
- ab wall is weakened -> testes/ ovaries descend from initial high position of post abdominal wall
- peritoneal outpouching (processus vaginalis) forms protruding through layers of ant abdominal wall
inguinal canal: initially, features
- processus vaginalis acquires coverings from
- transversalis fascia (deepest)
- musculature of internal oblique
- aponeurosis of ext oblique (superficial)
becomes tubular structure w multiple layers - basic structure of inguinal canal
inguinal canal: final development
- descent of testes into scrotum/ ovaries into pelvic cavity
men:
- descend with assoc. ducts/vessels/nerves which also pass through inguinal canal -> same fascial layers of ab wall
women:
- become assoc. w developing uterus, round lig (remnant of gubernaculum)
inguinal canal: concludes
- vaginalis obliterates
- if not, potential weakness and hernia may occur
inguinal canal: definition
- slit like passage downwards medially
- parallel to lower half of inguinal lig
- begins at deep inguinal ring -> superficial inguinal ring
inguinal canal: contents
- genital branch of genitalfemoral nn
- spermatic cord (men) round lig (women)
- ilioinguinal nn
inguinal canal: deep inguinal ring
- beginning of inguinal canal
- midway btw ASIS and pubic symphysis
- above inguinal lig, lateral to inferior epigastric vessels
inguinal canal: superficial inguinal ring
- end of inguinal canal
- superior to pubic tubercle
- triangular opening in aponeurosis of the external oblique with apex: pointing superolaterally and base formed by pubic crest
- medial/ lateral crus (remaining sides of triangle) attached to the pubic symphysis and pubic tubercle
inguinal canal: anterior wall
- aponeurosis of ext oblique
- reinforced laterally by lower fibres of internal oblique (potential site weakness)
- internal oblique mm covers deep inguinal ring contributing layer (cremasteric fascia) to covering structures tranversing inguinal canal
inguinal canal: posterior wall
- transversalis fascia
- reinforced along medial 1/3 by conjoint tendon
- conjoint tendon also supports superficial inguinal ring
inguinal canal: superior wall (roof)
- arching fibres of transversus abdominis and IO fibres
- from lateral points of origin from inguinal lig -> common medial attachment at conjoint tendon
inguinal canal: inferior wall (floor)
- medial half of inguinal lig
- this free margin of lowest part of EO forms gutter which contents of inguinal canal are positioned
- lacunar lig reinforces medial part of gutter
inguinal hernia: indirect
- most common
- more men vs women
- some/ all of processus vaginalis remaining
- peritoneal sac to enter inguinal canal passing deep inguinal ring
- peritoneal sac can traverse entire canal, exit superficial ring and continue into scrotum/ labia majus
inguinal hernia: direct
- peritoneal sac enters medial end of inguinal canal: weakened post wall
- common in mature men
- bulging occurs: medial/ inferior epigastric vessels
- does NOT traverse inguinal canal but may exit through superficial inguinal ring
posterior abdominal wall: muscles
- psoas major and minor
- quadratus lumborum
- iliacus
psoas major: origin
bodies/ transverse process T12-L5 + IV discs
psoas major: insertion
lesser trochanter
psoas major: innervation
anterior rami: L1,2,3
psoas major: action
flex the hip
psoas minor: origin
bodies of T12 + L1 IV discs
psoas minor: insertion
pectineal line, iliopubic eminence
psoas minor: innervation
anterior rami of L1
psoas minor: action
weak flexion of lumbar spine
iliacus: origin
iliac fossa
iliacus: insertion
lesser trochanter
iliacus: innervation
femoral n
iliacus: action
flexion of hip
quadratus lumborum: origin
TP of L1-L4
- rib 12
quadratus lumborum: insertion
TP of L5
- iliac crest
quadratus lumborum: innervation
- depresses and stabilises rib 12
- laterally flexes vertebral column
iliacus: features
- fills iliac fossa
- passes inferiorly, joins psoas major and attaches to lesser trochanter (iliopsoas)
- flexes thigh at hip when trunk is stabilised
