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

Abstract

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.

Extensor Triggering of Hand: A Rare Presentation and its Management

“…The extensor tendon at the dorsum of the hand is stabilized by a complex retinacular system called the dorsal hood [11]. The dorsal hood is made up of 3 structures: the sagittal, oblique, and the transverse bands [11,12].…”

“…The dorsal hood is made up of 3 structures: the sagittal, oblique, and the transverse bands [11,12]. At the MCP level the extensor tendons are stabilized by the sagittal bands and more distally between the MCP and the proximal IP joints by the transverse and the oblique bands, corresponding to a fibrous extension of the interosseous and lumbrical muscles, respectively [11,12]. The sagittal band is divided into a thin superficial layer and a thicker deep layer forming a channel through which the extensor tendon runs [11].…”

“…At the MCP level the extensor tendons are stabilized by the sagittal bands and more distally between the MCP and the proximal IP joints by the transverse and the oblique bands, corresponding to a fibrous extension of the interosseous and lumbrical muscles, respectively [11,12]. The sagittal band is divided into a thin superficial layer and a thicker deep layer forming a channel through which the extensor tendon runs [11]. The most important structure of the dorsal hood providing stability of the extensor tendon at the MCP level are the sagittal bands.…”

Ultrasound of Normal and Injured Ligaments and Retinacula of the Hand

“…26 The normal 10-to 15-degree ulnar deviation of the index and middle fingers may also predispose to radial sagittal band rupture. 33 The middle finger is the most commonly injured owing to its especially thin and long radial sagittal band and prominent metacarpal head. 26,29 Spontaneous rupture of a sagittal band can occur, particularly in patients with inflammatory joint disease.…”

“…The transverse and oblique fibers of the lumbrical and interosseous muscles, as well as the intertendinous intermetacarpal connections (juncturae tendinum), contribute to the stabilization of the extensor tendon over the proximal phalanx and MCP joint. 28,33 This may explain why isolated rupture of the sagittal band, without rupture of the oblique and transverse bands, may not lead to tendon dislocation. 28 Fibrosis in chronic sagittal band injuries may also stabilize the extensor tendon.…”