Faculty of Medicine, Department of Orthopedics and Traumatology, Hacettepe University, Ankara, Turkey.
Knee Surg Sports Traumatol Arthrosc. 2010 May;18(5):638-43. doi: 10.1007/s00167-010-1083-7. Epub 2010 Feb 25.
The Achilles tendon is the strongest and thickest tendon in the human body. It is also the commonest tendon to rupture. It begins near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles. The relative contribution of the two muscles to the tendon varies. Spiralisation of the fibres of the tendon produces an area of concentrated stress and confers a mechanical advantage. The calcaneal insertion is specialised and designed to aid the dissipation of stress from the tendon to the calcaneum. The insertion is crescent shaped and has significant medial and lateral projections. The blood supply of the tendon is from the musculotendinous junction, vessels in surrounding connective tissue and the osteotendinous junction. The vascular territories can be classified simply in three, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. This leaves a relatively hypovascular area in the mid-portion of the tendon where most problems occur. The Achilles tendon derives its innervation from the sural nerve with a smaller supply from the tibial nerve. Tenocytes produce type I collagen and form 90% of the cellular component of the normal tendon. Evidence suggests ruptured or pathological tendon produce more type III collagen, which may affect the tensile strength of the tendon. Direct measurements of forces reveal loading in the Achilles tendon as high as 9 KN during running, which is up to 12.5 times body weight.
跟腱是人体最强壮、最厚实的肌腱，也是最常发生断裂的肌腱。它起始于小腿中部附近，是腓肠肌和比目鱼肌的联合肌腱。两块肌肉对肌腱的相对贡献有所不同。肌腱纤维的螺旋化产生了一个集中应力的区域，并赋予了机械优势。跟腱的跟骨附着部是专门设计的，旨在帮助将肌腱的应力分散到跟骨上。跟骨附着部呈新月形，具有显著的内侧和外侧突出。肌腱的血液供应来自肌-腱结合部、周围结缔组织中的血管和骨-腱结合部。血管区域可以简单地分为三个区域，中段由腓动脉供应，近端和远端由胫后动脉供应。这使得肌腱中段的血液供应相对较少，大多数问题都发生在这里。跟腱由腓肠神经支配，胫神经也有较小的支配。腱细胞产生 I 型胶原，构成正常肌腱细胞成分的 90%。有证据表明，断裂或病理性的跟腱产生更多的 III 型胶原，这可能会影响肌腱的拉伸强度。直接测量力的结果显示，在跑步过程中，跟腱的受力高达 9 KN，这是体重的 12.5 倍。
