• High frequency (linear) ultrasound probe with probe cover and sterile gel
  • 50mm block needle (may change dependent on body habitus)
  • Suitable cleaning solution (e.g. hydrex pink 0.5% chlorhexidine)
  • Local anaesthetic in 2 x 20ml syringes
  • 2ml syringe with 25G (orange) needle for skin infiltration (if using)

The patient is positioned supine or semi-recumbent, with the arm abducted (Figure 1).

Figure 1. Patient positioning for left-sided SAPB.

The 5th rib is identified by scanning down from the clavicle. The probe is then rotated and held in the transverse plane (Figure 2).

Figure 2. Patient positioning and probe orientation.

The block is performed at the level of the 5th rib in the mid-axillary line via an in-plane technique (Figure 3).

Figure 3. Needle placement.

With the probe positioned as in Figure 3, the following image is obtained.

Figure 4. Ultrasound view for SAPB with relevant anatomy highlighted.

Prior to performing the block, colour Doppler should be used to identify any vascular structures which may lie in the path of the needle.

Figure 5. Ultrasound view with the thoracodorsal artery (T.A) seen (red circle). The thoracodorsal nerve may also be identified (not shown) as it runs with the artery. It can also be used as a landmark for performing the block.