On the picture on the right the needle (red) is inserted with the needle tip on the deep side of the transverse abdominis muscle (cyan arrows), after piercing the external (white asterix) and internal (yellow asterixs) abdominal oblique muscles
The local anaesthetic (yellow arrow) is deposited between the transverse abdominis muscle and the transversalis fascia (magenta line) which is loosely attached to the muscle
The local anaesthetic spreads across the aponeurosis and covers the deep side of the quadratus lumborum muscle (red asterix), where the subcostal and iliohypogastric nerves run across before the lateral cutaneous branches branch off
Fascia transversalis (magenta line), transverse abdominis muscle (cyan arrows), internal and external abdominis muscles (yellow and white asterixs), subcostal nerve (white line), lateral cutaneous branch (magenta arrow), anterior cutaneous branch (blue arrow), erector spinae (cyan asterix), psoas major (green asterix)
