- In the posterior precaudal and anterior caudal vertebrae rib shafts become hairlike structures.
- Each trochlear nerve makes its exit through the caudal tectum (the dorsal portion of the midbrain), immediately lateral to the frenulum of the superior medullary velum.
- The body of the seventh sometimes bears bilaterally, near its caudal border, a costal pit for the head of the first rib.
- The needle is inserted into the interscalene groove in a slightly medial, caudal, and posterior direction to avoid the vertebral column and vascular structures.
- A perpendicular is erected from the end plate of the most caudal vertebrae, whose inferior end plate tilts maximally to the concavity of the curve (inferior end vertebrae).