Ultrasound Blocks for the Anterior Abdominal Wall

1. Anatomy for Anesthesiologists | 17
between the IOM and the TAM (Rozen 2008). TAM plane is
delimitated superiorly by the costal margin, inferiorly by the
iliac crest, medially by the lateral border of the RAM, posteriorly
by the lumbodorsal fascia, superficially by the IOM and deeply by
the TAM.
Figure 1.5 – Innervation of the anterior abdominal wall (lines represent
T6 to T12 and iliohypogastric and ilioinguinal nerves).
Every segmental origin contributes to at least two nerves that
divide into several branches at the level of the anterior axillary
line (Barrington 2009). Each nerve gives muscular branches
innervating the overlying IOM and EOM and the RAM medially.
There is extensive and free branching and communication of
nerves within the TAM plane. As a consequence, there is a
considerable overlap in the dermal territories of adjacent
cutaneous nerves.
The intercostal and subcostal nerves communicate freely in
the TAM plane, and constitute a network corresponding to the