The change in position of the axillary nerve with rotation of the arm

Abstract

The axillary nerve is the most commonly injured nerve around the arm. In the deltopectoral approach, classical teaching states that lateral rotation of the humerus increases the distance between the subscapularis and the axillary nerve. This is the first anatomical study to quantify the distance change between the axillary nerve and subscapularis produced by arm rotation. Eight arms were placed in the supine position and a classical deltopectoral approach was performed. With digital calipers, measurements were made from the closest identifiable margin of the nerve to the inferior extent of the tenotomy. All measurements were made with the arm in 0 abduction and elbow in 90 of flexion, and repeated with the arm in 45 of medial rotation, 0 lateral rotation and 45 of lateral rotation. The mean d Axillary Nerve to subscapularis was recorded as 30.9 mm (95% CI:25.3-36.3), 39.4 mm(95% CI:34.1-44.8), and 46.1 mm (95% CI:41.1-51.2) for 45 MR, 0 , and 45 LR, respectively. Using paired-samples T-testing, the mean change in distance when moving from 45 MR to 0 was +8.5 mm (P < 0.0001), and from 0 to LR 45 , +6.7 mm (P < 0.0001). There is a significant difference in the distance between the subscapularis tenotomy and the axillary nerve with medial and lateral rotation. Laterally rotating the arm increased the distance by 6.7 mm, reaffirming that positioning the glenohumeral joint in a position of LR during subscapular tenotomy is protective against iatrogenic injury of the axillary nerve. Clin. Anat. 32:268-271, 2019.

Surgical anatomical landmarks for arthroscopic repair of subscapularis tendon tears

“…For open and arthroscopic surgeries, it is essential to know that the axillar nerve runs below the SSC tendon, being even closer in women and thin patients and with shoulder abduction and internal rotation [9]. We found a mean distance of 3.2 cm from the axillary nerve to the SSC footprint, consistent with previous reports [7] and confirming that there is enough room to carry out a safe repair with minimal risk of nerve damage when reattaching the inferior fibers of the tendon.…”

“…All measurements were systematically obtained with cadavers in supine position and the shoulders in neutral rotation, 0º abduction, and 90º elbow flexion. A vernier caliper (Aesculap, B. Braun) was used for measurements [7]. Mean and standard deviation were used to describe quantitative variables, and frequency and percentage were used for qualitative variables, assuming a normal distribution of values.…”

Ultrasonography‐guided anterior approach for axillary nerve blockade: An anatomical study

“…However, as described in previous reports, the first segment of the AN follows a course in close contact with the SSM (Duparc et al, ). Moreover, the position of the AN changes significantly between medial and lateral rotations of the arm (Fox et al, ). The therapeutic approach to this segment can be facilitated when the patient ’ s arm lies in an extended and externally rotated position; therefore, we have used the more realistic Thiel‐embalmed models here to describe the anatomical landmarks for reaching this region.…”