Department of Hand Surgery, Nara Medical University, Kashihara Nara, Japan.
Department of Anatomy, Faculty of Medicine, Chiang Mai University, Thailand.
J Hand Surg Am. 2021 Oct;46(10):930.e1-930.e9. doi: 10.1016/j.jhsa.2021.02.008. Epub 2021 Apr 9.
The sixth dorsal extensor compartment is a relatively common site of stenosing tenosynovitis in the upper extremity, but the exact location of stenosis is not fully understood. The objective of this study was to investigate the detailed anatomy of structures surrounding the extensor carpi ulnaris (ECU) tendon around the wrist.
Fifty fresh human cadaveric wrists were used for gross observation and morphology measurements of the sixth dorsal compartment and the ECU subsheath. An additional 13 wrists were used for histological examination. We evaluated the morphology of supporting structures in 3 regions: the ulnar groove (zone I), the ulnar styloid process (zone II), and the triquetrum (zone III).
The fibro-osseous tunnel comprising the ulnar groove and the overlying subsheath (zone I) stabilized the ECU tendon, and the subsheath had thin membranous collagen fibers attached to the periosteum. We consistently found the distal extension of ECU subsheath (zone II), which connected the ulnar styloid process and the dorsal radioulnar ligament. Variations in the length of the distal extension increased with the forearm in pronation. Collagen fiber thickness around the ECU tendon in zone II was greater than that of zone I. In zone III, the overlying extensor retinaculum and septa, which were composed of thick circumferential collagen structures, supported the ECU tendon by attaching to the triquetrum on both sides of the ECU tendon. We found the presence of an ulnar septum of the sixth compartment attached to the triquetrum in 84% of dissected wrists.
The ECU tendon was supported by the ECU subsheath, which had thin and elastic collagen fibers over the ulnar groove. Distal extension of the subsheath and surrounding radial and ulnar extensor retinaculum septa attached to the triquetrum provided thicker supporting structures.
Stenosing ECU tenosynovitis may occur not only in the ulnar groove but also in the more distal ulnar styloid process and triquetrum areas.
第六背侧伸肌间隔是上肢狭窄性腱鞘炎的一个相对常见部位，但狭窄的确切位置尚不完全清楚。本研究的目的是研究腕部周围伸肌骨间肌腱（ECU）周围结构的详细解剖结构。
50 个新鲜的人体尸体手腕用于第六背侧间隔和 ECU 鞘的大体观察和形态测量。另外 13 个手腕用于组织学检查。我们评估了 3 个区域（尺骨沟（I 区）、尺骨茎突（II 区）和三角骨（III 区））中支持结构的形态。
包括尺骨沟和上方鞘（I 区）的纤维骨性隧道稳定了 ECU 肌腱，鞘具有附着于骨膜的薄的膜状胶原纤维。我们始终发现 ECU 鞘的远端延伸（II 区），它连接尺骨茎突和背侧桡尺韧带。远端延伸的长度变化随着前臂旋前而增加。在 II 区，ECU 肌腱周围的胶原纤维厚度大于 I 区。在 III 区，上方的伸肌支持带和间隔，由厚的环形胶原结构组成，通过附着在 ECU 肌腱两侧的三角骨来支撑 ECU 肌腱。我们发现 84%的解剖手腕存在附着在三角骨上的第六间隔的尺侧间隔。
ECU 肌腱由 ECU 鞘支撑，ECU 鞘在尺骨沟上方具有薄而有弹性的胶原纤维。鞘的远端延伸以及周围的桡侧和尺侧伸肌支持带和间隔附着于三角骨，提供了更厚的支撑结构。
狭窄性 ECU 腱鞘炎不仅可能发生在尺骨沟，还可能发生在更远端的尺骨茎突和三角骨区域。
