Department of Orthopaedic Surgery, Tauranga Hospital, Bay of Plenty, New Zealand.
Department of Orthopaedic Surgery, Tauranga Hospital, Bay of Plenty, New Zealand.
J Shoulder Elbow Surg. 2021 Apr;30(4):729-735. doi: 10.1016/j.jse.2020.08.005. Epub 2020 Aug 24.
The location of the axillary nerve in the shoulder makes it vulnerable to traumatic or iatrogenic injury. Cadaveric studies have reported the location of the axillary nerve but are limited because of tissue compression, dehydration, and decay. Three-Tesla (T) magnetic resonance imaging (MRI) allows high anatomic resolution of neural structures. The aim of our study was to better define the location of the axillary nerve from defined bony surgical landmarks in vivo, using MRI scan.
Using MRI, we defined a number of anatomic points and measured the distance from these to the perineural fat surrounding the axillary nerve using simultaneous tracker lines on both images. Two observers were used.
A total of 187 consecutive 3-T MRI shoulder scans were included. Mean age was 57.9 years (range 18-86). The axillary nerve was located at a mean of 14.1 mm inferior from the bony glenoid at the anterior border, 11.9 mm from the midpoint, and 12.0 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P < .001), and between the anterior and posterior borders (P < .001). The axillary nerve was located at a mean of 12.6 mm medial to the humeral shaft at the anterior border, 9.9 mm at the midpoint, and 8.6 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P = .008) and between the anterior and posterior borders (P = .002). The mean distance of the axillary nerve from the anterolateral edge of the acromion was 53.3 mm (95% confidence interval [CI] 52.3, 54.2; range 33.9-76.3). The mean distance of the axillary nerve from the inferior edge of the capsule was 2.7 mm (95% CI 2.9, 3.1; range 0.3-9.9). There was a positive correlation between humeral head diameter and axillary nerve distance from the inferior glenoid (R = 0.061, P < .001). There was a positive correlation between humeral head diameter and distance from the anterolateral edge of the acromion (R = 0.140, P < .001).
Our study has defined the proximity of the axillary nerve from defined anatomic landmarks. The proximity of the axillary nerve to the inferior glenoid and medial humeral shaft changes as the axillary nerve passes from anterior to posterior. The distance of the axillary nerve from the anterolateral edge of the acromion remains relatively constant. Both sets of distances may be affected by humeral head size. The study has relevance to the shoulder surgeon when considering "safe zones" during arthroscopic or open surgery.
腋神经在肩部的位置使其容易受到创伤或医源性损伤。尸体研究已经报道了腋神经的位置，但由于组织压缩、脱水和腐烂，这些研究受到限制。3 特斯拉（T）磁共振成像（MRI）允许对神经结构进行高解剖分辨率成像。我们的研究目的是使用 MRI 扫描更好地定义腋神经在体内的位置，从定义的骨性手术标志开始。
使用 MRI，我们定义了一些解剖点，并使用两个图像上的同步跟踪线测量这些点与腋神经周围神经周围脂肪的距离。使用了两名观察者。
共纳入 187 例连续 3-T MRI 肩部扫描。平均年龄为 57.9 岁（范围 18-86 岁）。腋神经在前缘距骨性关节盂下 14.1 毫米处，在中点距离 11.9 毫米，在后缘距离 12.0 毫米。在前缘和中点之间（P <.001）和在前缘和后缘之间（P <.001）有显著差异。腋神经在前缘距肱骨轴内侧 12.6 毫米处，在中点距离 9.9 毫米，在后缘距离 8.6 毫米。在前缘和中点之间（P =.008）和在前缘和后缘之间（P =.002）有显著差异。腋神经从前肩峰前侧缘的平均距离为 53.3 毫米（95%置信区间[CI] 52.3，54.2；范围 33.9-76.3）。腋神经距关节囊下边缘的平均距离为 2.7 毫米（95%CI 2.9，3.1；范围 0.3-9.9）。肱骨头直径与腋神经距下关节盂的距离呈正相关（R = 0.061，P <.001）。肱骨头直径与腋神经从前肩峰前侧缘的距离呈正相关（R = 0.140，P <.001）。
我们的研究已经从定义的解剖标志定义了腋神经的接近程度。腋神经从前到后经过时，腋神经与下关节盂和肱骨内侧的距离接近。腋神经从前肩峰前侧缘的距离相对恒定。这两组距离都可能受到肱骨头大小的影响。这项研究对肩关节外科医生在关节镜或开放性手术中考虑“安全区域”时具有相关性。
