Syndrome of the Deep Branch of the Ulnar Nerve

The deep branch of the ulnar nerve risks compression as it passes through a fibro-osseus tunnel formed by the tendinous origin of the hypothenar muscles (Figure 24.1). While similar to ulnar nerve compression in Guyon’s tunnel (if only the motor branch is compressed), the abductor digiti minimi muscle is unaffected, as its innervation originates before the tendinous arch. Therefore, at times, this syndrome can be known as the syndrome of the tendinous arch of the hypothenar muscle or the syndrome of the deep branch of the

ulnar nerve; it is also known to Uriburu et al.