Dr Li (2021), in relation to the paper published recently in the Journal of Anatomy (Lucas et al., 2020) has suggested that the Ancient Chinese medicine may have added the 12th meridian to the human body based on detection of the pulse on the median artery at the wrist.

Brachial artery of the arm and the common interosseous artery of the forearm are derived from the foetal axial artery of the forelimb. Median artery develops from the common interosseous artery and maintains the main blood supply to the developing hand, initially. Ulnar and radial arteries are terminal branches of the brachial artery (Moore et al., 2020), and as they develop and take over the functions of the median artery, it undergoes gradual regression. This regression commences at about the eight week of gestation and completes during the post-foetal life (Eid et al., 2011; Jones & Ming, 1988). This is the common pattern of development of the median artery, but in about 30% of people, this artery persists and remains functional throughout the life (Lucas et al., 2020). Two phenotypes of the median artery, palmar and antebrachial with the approximate incidences of 20% and 76%, respectively, have been reported (Claassen et al., 2008; Rodriguez-Niedenfuhr et al., 1999). The palmar type artery is large, long, enters and supplies the hand. The other phenotype is small, short, supplies the forearm and ends before reaching the wrist joint (Valdecasas-Huelin et al., 1979). Median artery of the palmar phenotype enters the hand via the carpal tunnel and either contributes to form the superficial palmar arch with the ulnar artery or directly forms one or more of the common digital arteries 1–3 (Claassen et al., 2008; Cheruiyot et al., 2017; Rodriguez-Niedenfuhr et al., 1999). The observation in Chinese medicine that the 12th meridian, Hand Jue Yin Meridian runs along the path taken by the persistent median artery (Li 2021) is very interesting. According to the diagram presented in Li (2021), the segment of the 12th meridian from the elbow region to the distal end of the carpal tunnel could be in the path of the median artery of the palmar phenotype. Thereafter, the median artery either forms the superficial palmar arch with the ulnar artery or directly forms one or more of the common digital arteries 1–3 (Claassen et al., 2008; Cheruiyot et al., 2017; Lucas et al., 2020; Rodriguez-Niedenfuhr et al., 1999). Twelfth meridian from the distal end of the carpal tunnel to the third finger appears to run vertically across the superficial palmar arch and between 1st and 2nd common digital arteries (Langevin & Yandow, 2002; Li, 2021). Therefore, in this part, the 12th meridian may not be directly related to the median artery. The path of the segment of the 12th meridian between elbow and wrist joints could be along the median arteries of both phenotypes. Furthermore, the