Rectus sheath

contents

Superior + inferior epigastric vessels
Posterior intercostal nerves (T7-11)

T12 neurovascular bundles
Rectus abdominis
Pyramidalis muscle

composition

aponeurosis of external oblique
aponeurosis of internal oblique
aponeurosis of tranversus abdominis

arcuate line

Below arcuate line, all the aponeuroses lie anterior to rectus abdominis
therefore rectus abdominis is in direct contact with transversalis fascia
forms part of pelvic brim

regional anaesthesia

rectus sheath blocks
indication: analgesia after surgery with midline incision
aiming for posterior wall of rectus sheath - otherwise LA may only spread to one of the 'six packs'