Abstract
The ulnar artery (UA) is one of the two major arteries of the forearm. Compared to the radial artery, the UA is rarely used in coronary artery bypass (CABG) surgery, partially due to misconceptions regarding its anatomy. This narrative literature review aimed to evaluate current understanding of UA anatomy, to evaluate its feasibility as a conduit for CABG. Following a systematic search, 86 papers were included that described the gross and microscopic anatomy of the UA or its major branches using a range of techniques in living people and cadaveric specimens. Of the 60 studies that described UA gross anatomy, two measured its mean length (23 cm, approximately 15 cm of which is harvestable). Luminal diameter (32 studies) ranged from 1.48–5.71 mm proximal to 2.20–3.58 mm at or distal to the wrist; these findings demonstrate the UA is of similar size to other common conduits. Descriptions of the arrangement of the superficial palmar arch (SPA) (25 studies) lacked consistency; however, more than half of SPAs were formed by the UA and a branch of the radial artery (55.6%, 1350/2430), indicating safe UA harvest is feasible in some people. Microscopically (3 studies), the UA is predominantly muscular, with a mean±SD wall thickness of between 0.10±0.08 mm and 0.56±0.16 mm. The diameter of the UA is well documented, but high-quality studies of its length, and microscopic anatomy (e.g., tunica media and internal elastic lamina composition) and behaviour are required to better understand its feasibility as a CABG conduit.