Peer-review started: August 15, 2022
First decision: October 21, 2022
Revised: November 1, 2022
Accepted: December 21, 2022
Article in press: December 21, 2022
Published online: January 15, 2023
The sympathetic nervous system is primarily responsible for controlling the peripheral arteries. It decreases the size of medium and large peripheral arteries to slow the blood flow rate.
There is insufficient information to determine which artery receives more postganglionic sympathetic innervation from which peripheral nerve.
To determine if the ulnar and median nerves contribute equally to sympathetic stimulation of the brachial artery.
We developed a neurophysiological autonomous test that measured the effects of peripheral sympathetic fibres on peripheral arteries. The brachial artery baseline diameter and flow rate were measured in the right arm of the patients. Afterwards, electrical stimulus was applied to the medial nerve for 5 s. Through electrical sympathetic activation, the vessel diameter and overall flow rate will decrease. After 7 d, a similar experiment was repeated using the ulnar nerve.
The differences in diameter and flow rate of the brachial artery in response to median and ulnar nerve activation were compared. In the total group, no significant difference in diameter was seen between medial and ulnar nerve stimulation (P = 0.648). The difference in absolute slowdown of flow rate between median nerve stimulation and ulnar nerve stimulation was not statistically significant for the entire group (P = 0.733).
The brachial artery serves as a target organ and is equally innervated by the median and ulnar nerves.
Expanding similar neurophysiological research to other arteries in the upper and lower limbs will contribute to advancing the field of functional neuroanatomy.