Surg Radiol Anat (2009) 31:77–83 DOI 10.1007/s00276-008-0402-x 123 ORIGINAL ARTICLE Anatomo-histological analysis of the juncturae and their relations to the extensor tendons to the dorsum of the hand Yelda Pinar · Okan Bilge · Figen Govsa · Servet Celik · Huseyin Aktug Received: 19 March 2008 / Accepted: 11 August 2008 / Published online: 26 August 2008  Springer-Verlag 2008 Abstract The juncturae tendinum (JT) may coordinate the extension of hand, force redistribution and the stabiliza- tion of the metacarpophalangeal joint. The JT were studied for their gross appearance, shape, thickness, location and histological examination with the dorsum of the hand in 54 cadavers. The JT were identiWed into three groups accord- ing to their anatomo-histological features. The type 1 was observed in 57.4% of the cases in the second IMC and in 16.7% of the cases in the third IMC. The type 2 was detected in 3.7% of the cases in the second IMC and in 59.3% of the cases in the third IMC space. The type of 3Y was accounted for 14.8% JT in the third IMC space and 53.7% JT in the fourth space. The type of 3r was found in 5.55% of the cases in the third IMC and in 37% of the cases in the fourth IMC space. In the histologic examination, the Wbers of types 1 and 2 JTs were straight. Type 3 JTs were composed of regularly oriented parallel and crosswise bun- dles of tendineous tissue. This study is important in terms of giving accurate knowledge on the anatomo-histological analysis of the JTs and their relations to the extensor ten- dons to the dorsum of the hand. An understanding of the structures of the JTs and the interactions between the ten- dons of the Wngers is of utmost importance in hand assess- ment, during the reconstructive procedures such as considering the tendons to be transferred. Keywords Extensor digitorum · Juncturae · Extensor tendon · Reconstruction · Hand surgery Introduction On the dorsum of the hand, the extensor digitorum (ED) tendons are linked distally by oblique interconnections, juncturae tendinum (JT). The JT connect the extensor ten- dons proximal to the metacarpophalangeal joint [20, 26, 31]. Important functional roles have been attributed to the JT such as preventing independent extension of the digits, spacing of the ED tendons, force redistribution, coordina- tion of extension and stabilization of the metacarpopharyn- geal joints [1, 4, 22, 27, 28]. As the JTs are bridge and mask tendon lacerations, they are clinically important. Lacera- tions proximal to the JT may still allow the extension of the involved Wnger by pulling from the adjacent Wnger passing through the JT [10, 18, 20]. The JT are more useful for reparing the dorsal aponeurosis and identiWcation of the ED tendons of the hand. In hand surgery, tendon transfers; the use of Xaps prepared from the dorsum of the hand in Wnger reconstruction, have an important role [3, 7, 10, 20]. The Xaps taken from the meta- carpal level are stretched towards the Wnger and used in the bruises in Wngers. It is only possible with a successful recon- struction to preserve hand motion dynamic in human, who particularly uses his hands very much. Furthermore, hand anatomy and dynamic should have been clearly deWned in order to apply the right surgical procedure and minimize the post-operative complications in hand traumas. Several anatomical studies described the course and location of the JTs and their relations to the extensor ten- dons of the dorsum of the hand in detail [6, 8, 9, 14, 19, 22, 26, 29]. Previous authors classiWed the JTs into three types, Y. Pinar · O. Bilge · F. Govsa (&) · S. Celik Department of Anatomy, Faculty of Medicine, Ege University, 35100 Izmir, Turkey e-mail: Wgen.govsa@ege.edu.tr; fgovsa@yahoo.com H. Aktug Department of Embryology and Histology, Faculty of Medicine, Ege University, Izmir, Turkey