Functional anatomy of the dorsal hood or the hand: correlation of ultrasound and MR findings with cadaveric dissection

The main aim of this study was to provide an overview of the anatomy of the dorsal hood (DH) based on the dissection of sixteen cadaver hands, correlated with magnetic resonance (MR) and ultrasound findings. A secondary aim was to assess the function of components of the DH. Sixteen embalmed hands were evaluated by MRI and ultrasound before being dissected. Each hand was photographed during each stage of dissection. Secondly we evaluated the role of the different structures of the DH in the stability of the extensor tendon by transection of the different components alternatively at the ulnar and radial sides. MR, ultrasound, and dissection showed that the extensor tendon (ET) is stabilized by the sagittal band (SB) at the level of the metacarpophalangeal (MCP) joint and more distally by the transverse and the oblique bands, respectively. Transection of the radial SB of the second finger leads systematically to ulnar dislocation of the ET. The transection of the ulnar DH does not lead to instability of the ET. The SB is the most important structure of the DH in the stability of the ET at the MCP level. Rupture of the radial SB of the second finger leads systematically to ulnar dislocation of the ET.