[doi: 10.5505/2017ichc.PP-226]
Review of the histological features of tendon sheath and vinculum
Seda Develi1, Yasin Ilgaz22Departmant of Histology and Embryology, Gulhane Military Medical Academy, Ankara, Turkey
Tendon is a dense cord of fibrous connective tissue. Tendons connect muscle with the bones. They are composed of collagen fibers which forming dense regular connective tissue. They are covered by irregular connective tissue sheaths called peritendineum or synovial sheet. Synovial sheet is composed of collagenous fibers which are mainly composed of type I and type III collagen fibrils. The inner layer of synovial sheath is called vagina synovialis or stratum synoviale. This layer forms a closed space and produces peritendinous fluid which reduces the friction and provides gliding of the tendon. The outer layer of synovial sheet is called vagina fibrosa or stratum fibrosum which confines the tendon to osseous groove. Histological specimen of tendon sheath of flexor digitorum profundus muscle (fourth digit on the middle phalanx) is seen in Figure 1. As seen in Figure 1; vessels supplying the tendon sheath are mainly located in the midsection of the sheath. This area is the attachment site of vinculum (pl. vincula). Vinculum also known as mesotendineum is a band of connective tissue which lies between palmar surface of the phalanxes and dorsal surface of the tendon sheaths. Main function of the vinculum is to carry vessels which are supplying the tendon sheath and tendon. In anatomic terminology; there are two types of vinculum- vincula longi and breve. These ligamentous structures are mainly found in digits of hand foot and they are located between phalanxes and tendon sheath on the median plane. In terms of vascularization of tendon and tendon sheath, their location should be kept in mind in procedures such as rupture repair, transection of digital pulley systems or local anesthesia.
Representative photographs of the blood vessels in the tendon sheath stained with Masson trichrome.
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Figure: Vascular structures (arrows) of the tendon sheath are mostly located in the midsection of the sheath, Scale bar 500 µm.