Compression of the Deep Palmar Branch of the Ulnar Nerve by an Anomalous Muscle

Abstract

1. A case of compression of the deep palmar branch of the ulnar nerve by an accessory abductor minimi digiti muscle is described. 2. The morphology of abnormal muscles in the hypothenar region is discussed. 3. Five previously reported cases of ulnar nerve compression at the wrist by an anomalous muscle are reviewed. 4. When symptoms are produced by an anomalous hypothenar muscle, they seem to be related to the anatomical site of the muscle and the presence of muscle hypertrophy. Occupational factors may be important in producing this hypertrophy.

An anomalous accessory flexor digiti minimi profundus muscle: A case study

“…Roberts (1972) and Lahey and Aulicino (1986) identify anomalous muscles originating from PL acting as accessory muscles of abduction and flexion of the fifth digit, while Still and Kleinert (1973) describe an aberrant PL muscle passing through Guyon's canal. An anomalous muscle in the lower forearm in the absence of PL was referred to by Jeffery (1971) as accessory abductor minimi digiti. However, none of these muscles displayed attachments corresponding to the muscle described here.…”

“…Compression of the ulnar nerve by this muscle can occur within Guyon's canal. Although ulnar nerve compression at the level of the wrist by anomalous muscles is rare (James et al, 1987;Sheppard et al, 1991), it is not uncommon, as several cases have been reported (Jeffery, 1971;Still and Kleinert, 1973;Sälgeback, 1977;Lahey and Aulicino, 1986;James et al, 1987). It has also been suggested that ulnar artery thrombosis may be associated with an anomalous muscle in Guyon's canal (Pribyl and Moneim, 1994).…”

“…A clear understanding of this variation is important to radiologists and family physicians for diagnostic purposes as well as hand surgeons when undertaking corrective surgical procedures. Probably the most variable flexor muscle in its expression is palmaris longus (Jeffery, 1971;Roberts, 1972;Still and Kleinert, 1973;Tonkin and Lister, 1985;Lahey and Aulicino, 1986;Kostka and Steen, 1990). A flexor of the wrist, the flexor carpi ulnaris may be variable Pribyl and Moneim, 1994).…”

“…These accessory muscles may simulate soft-tissue tumors (Thomas, 1958;Lipscomb, 1960). Often anomalous muscles can result in nerve compression (Jeffery, 1971;Still and Kleinert, 1973;Sägleback, 1977;Turner and Caird, 1977;Lahey and Aulicino, 1986;James et al, 1987;Sheppard et al, 1991) and have been reported in a case of arterial thrombosis (Pribyl and Moneim, 1994). Knowledge of the existence of muscle anomalies as well as the location of compression is useful in determining the pathology and appropriate treatment for compressive neuropathies (Lahey and Aulicino, 1986 fied an anomalous forearm flexor muscle during a routine prosection and a general survey of the literature failed to reveal a similar observation (Wood, 1868;Bergman et al, 1988).…”

Unusual origin of abductor digiti minimi and its clinical significance

“…In previous descriptions a similar accessory ADM muscle beam was reported to originate from palmaris longus and the palmar aponeurosis (Wood, 1867;Soldado-Carrera et al, 2000), from the flexor carpi radialis tendon (Bakinde et al, 2005), from the flexor carpi ulnaris tendon (Hill et al, 2006), from the transverse carpal ligament (Netscher and Cohen, 1997), solely from the deep antebrachial fascia (Jeffery, 1971;Salgeback, 1977;Turner and Caird, 1977) or both from the flexor retinaculum and deep antebrachial fascia (Sheppard et al, 1991;Sanudo et al, 1993;Netscher and Cohen, 1997;Vollala et al, 2005). In the present case the additional ADM took origin from the deep antebrachial fascia and the tendon of FDS muscle to the middle finger.…”