This articulation is present in all but the eleventh and twelfth ribs. Ribs 1 to 10 have two joints in close proximity posteriorly; the costovertebral joints and the costotranseverse joints. This arrangement restrains the motion of the ribs allowing them to work in a parallel fashion during breathing. If a typical rib had only one joint posteriorly the resultant swivel action would allow a rib to be non-parallel with respect to the neighboring ribs making for a very inefficient respiratory mechanism. The ventral rami innervate the costotransverse joints. Therefore, therapeutic medial branch blocks are ineffectual.
The ligaments of the joint are:
Thoracic costotransverse joint pain patterns: a study in normal volunteers.(Research article)(Clinical report)
Oct 15, 2008; Authors: Brian A Young (corresponding author) ; Howard E Gill ; Robert S Wainner ; Timothy W Flynn  Background The...