Ultrasonographic Identification of the High-Risk Zone for Medial Antebrachial Cutaneous Nerve Injury in the Elbow

OBJECTIVE: To demonstrate the sonoanatomy of the medial antebrachial cutaneous nerve (MACN) in the elbow region using high-resolution ultrasonography (HRUS) to identify areas at a high risk of MACN injury. METHODS: A total of 44 arms were included in the study. In the supine position, the participants’ arms were abducted 45° with the elbow fully extended. The MACN was visualized in the transverse view. The anterior branch of the MACN (ABMACN), posterior branch of the MACN (PBMACN), and location of the branching sites were determined. The distance between the ABMACN and superficial veins, including the basilic vein (BV) and median cubital veins (MCV) was measured. For the PBMACN, the distance to the ulnar nerve (UN) and to BV were measured. RESULTS: The MACN was subdivided into 2.18±1.00 branches, including ABMACN and PBMACN. The ABMACN and PBMACN were subdivided into 1.60±0.78 and 1.07±0.25 branches, respectively. The branching point of the MACN was 8.40±2.42 cm proximal to the interepicondylar line (IEL). We demonstrated that the ABMACN is located close to the BV and MCV in the elbow region, and the PBMACN was located approximately 1 cm and 0.8 cm anterior to the UN and posterior to the BV at the IEL level, respectively. CONCLUSION: Considering the location of the MACN, including ABMACN and PBMACN, clinicians can perform invasive procedures around the elbow region more carefully to lower the risk of MACN injury.