Relationship between Anconeus Epitrochlearis and Ulnar Motor Nerve Conduction Velocity

ABSTRACT

Objective@#To determine the incidence of anconeus epitrochlearis (AE) muscle and evaluate the correlation between AE muscle and ulnar motor nerve conduction velocity (NCV). Method: Forty healthy volunteers (80 arms) were evaluated. Ulnar motor nerve conduction study was performed. NCVs at the forearm and across the elbow were calculated. Ultrasonography (US) was used to obtain a transverse scan view of the cubital tunnel and confirm the presence of the AE muscle. Cross-sectional areas (CSAs) of following structures were obtained: ulnar nerve (UNCSA), cubital tunnel (CTCSA), and AE (AECSA). AECSA was divided by CTCSA to obtain the AE/CT ratio. Pearson correlation coefficient (PCC) was calculated to evaluate the relationship between NCV across elbow and each variable obtained by US. @*Results@#Sixty-three (78.75%) of eighty arms showed the presence of AE muscle. NCV had no significant correlations with sonographic variables. However, when 17 arms with a relatively low NCV value (≤ 60 m/s) were analyzed, NCV showed significant correlations with AECSA (PCC: r = −0.674, p=0.003) and AE/CT ratio (PCC: r = −0.516, p=0.034). @*Conclusion@#When all 63 cases with AE muscle were analyzed, ulnar NCV showed no significant correlations with sonographic variables. However, when those with NCV value of 60 m/s or less were analyzed, NCV showed significant negative correlations with AECSA and AE/CT ratio.