The primary issue with a lesion of the tenth dorsal segment is the effect on the lesser splanchic nerve as well as the tenth dorsal nerves. The lesser splanchic nerve provides motor tone, vaso-motor tone, sensory tone, secretory tone, and trophic tone to the: kidneys, ureter, ovaries/testes, fundus of the uterus/prostate gland, stomach, liver, spleen, and pancreas. As with any lesion there may be inhibition or excitation of function for any of the connected structures.
Consider that the tenth dorsal segment is the beginning of the transition from a strict dorsal vertebrae towards a lumbar vertebrae. The tenth dorsal is the last segment with a rib that attaches to the costal cartilage. The tenth dorsal segment is also fairly distant from the appendages so accurate leverage must be appropriately considered.
After typing the above paragraph I want to pose some possible solutions to dealing with treatment of the tenth dorsal. Since the tenth dorsal sits almost at the bottom of the upper girdle and muscular connections make it slightly more difficult to use the arm as a lever it is likely more appropriate to use the upper girdle/thorax as a lever. As long as the full lesion pattern is understood, employing the upper girdle as a lever provides many options to the Operator with very little effort. Due to the connection of the tenth rib to the costal cartilage, any movement of the cage has the ability to affect the tenth dorsal segment. Whether the patient is seated, side lying, supine, or prone there is direct access to the tenth dorsal segment through the tenth rib and the cage as a unit. If used in relation to the rib cage as a unit, the arm will be an effective lever as long as the Operator keeps in mind that they have to use the whole cage before they get to the tenth dorsal segment.
When treating the cage as a unit there is the added bonus of improving the balance of cavity pressures allowing for more appropriate fluid dynamics. When the thorax/upper girdle is balanced the respiratory pump will function more efficiently and thus passive circulation (venous blood flow and lymphatic flow) will improve (Joanne Hancock actually noted this in my post on the tenth rib).
While I am using Marion Clark’s work to guide these posts I am also going through other ideas as part of my own current growth with Osteopathy. I always aim to highlight how the principles guide our understanding of working with a patient. Keep the structures you are treating foremost in your mind, remember the related structures, then apply that knowledge through the lever, screw, and wedge!