Deep Block

The deep SAPB is performed with the same needle placement (see Figure 3). The needle is directed down onto the rib, taking care to avoid the pleura. It is then moved back slightly and local anaesthetic injected between the rib and serratus anterior muscle. This approach may be favourable in those with distorted anatomy secondary to rib fractures, or in the elderly where muscle layers may be poorly defined.

Figure 7. The needle path is shown in yellow, and the potential spread of local anaesthetic in purple between the rib and serratus anterior (S.A).