Ligaments like the superior costotransverse ligament
seem to have fenestrations , and these porous anatomical structures can be speculated to allow anterior spread of the local anesthetic.
These boundaries include the parietal pleura ventrolaterally; heads of the ribs, transverse process, and superior costotransverse ligament
dorsally; and vertebra, intervertebral discs, and intervertebral foramina medially.
Loss of resistance or a subtle "pop" was felt as the needle passed through the superior costotransverse ligament
. After negative aspiration, 5 ml of the drug according to the group was administered per site.