Mercer D, Morrell N T, Fitzpatrick J, Silva S, Child Z, Miller R, DeCoster T A
The University of New Mexico Albuquerque, NM 87131-0001, USA.
Iowa Orthop J. 2011;31:231-5.
Injury to the saphenous nerve at the ankle has been described as a complication resulting from incision and dissection over the distal tibia and medial malleolus. However, the exact course and location of the distal saphenous nerve is not well described in the literature. The purpose of this study was to determine the distal limit of the saphenous nerve and its anatomic relationship to commonly identified orthopaedic landmarks and surgical incisions.
Sixteen cadaveric ankles were examined at the level of the distal tibia medial malleolus. An incision was made along the medial aspect of the lower extremity from the knee to the hallux to follow the course and branches of the saphenous nerve under direct visualization. We recorded the shortest distance from the most distal visualized portion of the saphenous nerve to the tip of the medial malleolus, to the antero-medial arthroscopic portal site, and to the tibialis anterior tendon.
The saphenous nerve runs posterior to the greater saphenous vein in the leg and divides into an anterior and posterior branch approximately 3 cm proximal to the tip of the medial malleolus. These branches terminate in the integument proximal to the tip of the medial malleolus, while the vein continues into the foot. The anterior branch ends at the anterior aspect of the medial malleolus near the posterior edge of the greater saphenous vein. The posterior branch ends near the posterior aspect of the medial malleolus. The average distance from the distal-most visualized aspect of the saphenous nerve to the tip of the medial malleolus measured 8mm +/-; 5mm; from the nerve to the medial arthroscopic portal measured 14mm +/-2mm; and from the nerve to the tibialis anterior measured 16mm +/-3mm. In only one case (of 16) was there an identifiable branch of the saphenous nerve extending to the foot and in this specimen it extended to the first metatarsophalangeal joint. The first metatarsophalangeal joint was innervated by the superficial peroneal nerve in all cases. Small variations were also noted.
This study highlights the proximity of the distal saphenous nerve to common landmarks in orthopaedic surgery. This has important clinical implications in ankle arthroscopy, tarsal tunnel syndrome, fixation of distal tibia medial malleolar fractures, and other procedures centered about the medial malleolus. While the distal course of the saphenous nerve is generally predictable, variations exist and thus the orthopaedic surgeon must operate cautiously to prevent iatrogenic injury. To avoid saphenous nerve injury, incisions should stay distal to the tip of the medial malleolus. The medial arthroscopic portal should be more than one centimeter from the anterior aspect of the medial malleolus which will also avoid the greater saphenous vein. Incision over the anterior tibialis tendon should stay within one centimeter of the medial edge of the tendon.
隐神经在踝关节处的损伤被描述为胫骨远端和内踝切开及解剖的并发症。然而，文献中对隐神经远端的确切走行和位置描述并不充分。本研究的目的是确定隐神经的远端界限及其与常见骨科标志和手术切口的解剖关系。
对16具尸体踝关节在胫骨远端和内踝水平进行检查。沿下肢内侧从膝关节至拇趾做一切口，在直视下追踪隐神经的走行和分支。我们记录了从隐神经最远端可视部分到内踝尖、前内侧关节镜入口部位以及胫骨前肌腱的最短距离。
隐神经在小腿位于大隐静脉后方，在内踝尖近端约3厘米处分为前支和后支。这些分支在内踝尖近端的皮肤内终止，而静脉则延续至足部。前支在内踝前方大隐静脉后缘附近终止。后支在内踝后方附近终止。从隐神经最远端可视部分到内踝尖的平均距离为8毫米±5毫米；从神经到内侧关节镜入口的距离为14毫米±2毫米；从神经到胫骨前肌的距离为16毫米±3毫米。在16例中只有1例有可识别的隐神经分支延伸至足部，在该标本中其延伸至第一跖趾关节。在所有病例中，第一跖趾关节均由腓浅神经支配。也注意到了一些小的变异。
本研究强调了隐神经远端与骨科手术中常见标志的接近程度。这在踝关节镜检查、跗管综合征、胫骨远端内踝骨折固定以及其他以内踝为中心的手术中具有重要的临床意义。虽然隐神经的远端走行通常是可预测的，但仍存在变异，因此骨科医生必须谨慎操作以防止医源性损伤。为避免隐神经损伤，切口应位于内踝尖远端。内侧关节镜入口应距内踝前方超过1厘米，这也将避免大隐静脉。胫骨前肌腱上方的切口应位于肌腱内侧边缘1厘米范围内。
