title: Radial nerve innervation of the first dorsal interosseous muscle: A functional study.
abstract: A recent cadaver study described that 25% of the superficial radial nerves (SRN) investigated sent a contributing nerve branch into the first dorsal interosseous (1DI) muscle. This high degree of anatomical variation was unexpected, as the 1DI muscle is typically viewed as receiving its innervation from the ulnar nerve. The purpose of this study was to explore this possible SRN innervation of the 1DI muscle using electrophysiological tests on living subjects. Fourteen subjects participated and procedures were completed on their upper extremities bilaterally. Subjects were positioned supine and testing for the presence of a compound motor action potential (CMAP) was completed to determine if the 1DI muscle could be stimulated with activation of the ulnar nerve and the SRN. In all the 28 extremities examined, ulnar nerve stimulation resulted in clear elicitation of a CMAP in the 1DI muscle but stimulation of the SRN did not. The obtained findings do not support an atypical voluntary motor innervation of the 1DI muscle by the SRN with an incidence approaching the 25% reported previously.
authors.affiliation: School of Physical Therapy, Belmont University, Nashville, Tennessee, USA.
authors.forename: J
authors.initials: J
authors.lastname: Brokaw
authors.forename: S
authors.initials: S
authors.lastname: Craig
authors.forename: S
authors.initials: S
authors.lastname: DeNeal
authors.forename: K
authors.initials: K
authors.lastname: Morris
authors.forename: J
authors.initials: J
authors.lastname: Halle
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011826:Radial Nerve / Q000502:physiology*; D055815:Young Adult