Clinically relevant anatomical variations in the posterior intercostal neurovascular bundle.

Abstract

Background: This study focused on the variations of the structures in the posterior intercostal neurovascular bundle.

Materials and methods: Dissected the posterior intercostal spaces (1st-11th) of 12 cadavers from the vertebral body to the anterior to the mid-axillary line. Variations in the arrangement, course, relations, patterns, and rare features of the structures were observed.

Results: In the neurovascular bundle, four types of arrangement of the structures from superior to inferior were observed. Presence of a foetal connecting branch between the left 9th and 10th posterior intercostal veins and the left 7th and 8th intercostal nerves. The posterior intercostal artery passes lateral to the white ramus communicans of the corresponding intercostal nerve. The 1st thoracic ventral ramus and 2nd intercostal nerve are connected to the stellate and 2nd thoracic ganglia by different white rami communicantes. In the 1st intercostal space, type A and D intrathoracic nerves of Kuntz were observed. Collateral intercostal nerves have different points of origin, reach the superior border of the inferior rib, and have communications and terminations. A left 7th collateral intercostal nerve originated from the connecting branch between the 7th and 8th intercostal nerves. A left 9th lateral cutaneous nerve originated from the collateral intercostal nerve.

Conclusions: Intercostal nerve block and thoracic clinical procedures require an understanding of the variations in the neurovascular bundle. Awareness of the different types of intrathoracic nerves of Kuntz and white rami communicantes and foetal connecting branches between adjacent intercostal nerves and posterior intercostal vessels in adults are useful in surgical approaches.