Ultrasound Blocks for the Anterior Abdominal Wall

1. Anatomy for Anesthesiologists | 15
Figure 1.3 – The musculo-aponeurotic layer.
Anteriorly, the rectus abdominal muscle (RAM) lies on both
sides of the vertical midline or linea alba. On either side of the
RAM, the musculo-aponeurotic plane is made up respectively,
from the anterior to the posterior surface, of three flat muscular
sheets: the external oblique muscle (EOM), the internal oblique
muscle (IOM) and the transverse abdominal muscle (TAM). The
pattern of relative abdominal muscle thickness is RAM > IOM >
EOM > TAM (Figure 1.4) (Rankin 2006).
The plane between the IOM and the TAM is the target for most
of the abdominal blocks (Figure 3.4).
Blood Supply to the Anterior Abdominal Wall
Knowledge of abdominal wall vascularization is necessary for a
safe performance of blocks. Three major arterial branches
supply blood to both sides of the anterior abdominal wall (Figure
1.1). The deep inferior epigastric artery and vein originate from