Tendon and neurovascular bundle displacement in the palm with hand flexion and extension: An MRI and gross anatomy correlative study

Abstract

This study evaluated the correlative use of MRI methods and gross anatomy to monitor tendon displacement in the central region of the palm at rest and during flexion and extension of the metacarpophalangeal and interphalangeal joints with respect to the corresponding neurovascular bundles (NVBs). In all of the samples the neutral and extended positions showed the NVB to be palmar with respect to the flexor tendons, while during flexion tendon displacement caused the NVB to be dorsal to both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons. T1-weighted MR images correlated with gross anatomical slides demonstrated that significant changes occur in the relative positions of the flexor tendons and associated NVBs of the palm upon flexion and extension. MOST FUNCTIONAL ANATOMIC STUDIES of tendon and nerve displacement in the hand (1-3) have focused on biomechanical stresses and dynamic alterations in wrist anatomy. One of the main focuses of these studies is carpal tunnel syndrome (2). In this regard, noninvasive magnetic resonance imaging (MRI) methods have been used to illustrate palmar anatomy with the hand in the neutral (resting) position (4). Dynamic anatomic changes that occur in the palm, in particular, in terms of the positioning of the palmar tendons and neurovascular bundles (NVBs; palmar digital artery and nerve) as a function of flexion and extension of the hand have not been fully investigated by an MRI and gross anatomy correlative study.Aside from the basic interest attached to defining this functional anatomy, such studies may contribute to our understanding of lacerations that occur in the central region of the palm, known as zone III (5), the area of the lumbrical origin between the distal margin of the transverse carpal ligament and the beginning of the critical area of pulleys or first annulus. Lacerations that occur just proximal to the head of the metacarpals are among the most commonly encountered injuries to the hand. The structures that are most readily damaged in such injuries are those that are the most superficial.Accordingly, in this study we used MRI to evaluate tendon displacement in zone III of the palm (Fig. 1) with respect to the corresponding NVBs at rest and during flexion and extension. MATERIALS AND METHODS CadaversExperiments were performed on 10 non-embalmed cadaveric right arms (from five males and five females; mean age at death ϭ 65 years) that were disarticulated at the humerus. A custom-made device (Fig. 2) was used to ensure reproducible positioning and standardized grip force. The donors were free of known musculoskeletal pathologies. Images were acquired for all samples with the hand in the resting position. Four hands were then imaged in flexion and extension. Differences observed during flexion were later confirmed by analysis of four additional specimens in flexion. For all images the arm was secured by a bone screw inserted through the wrist that allowed movement of the distal and proximal interphalangeal and metacarpophalangea...

Deformation of the median nerve at different finger postures and wrist angles

“…The present study demonstrates that finger flexor tendon gliding during wrist flexion causes the highest deformation of the MNCSA, followed by wrist extension. This may be caused by the tendon and dorsal-palmar displacement of the median nerve in the carpal tunnel at wrist flexion and extension which deviates from that in the neutral position ( Canuto et al, 2006 ; Mogk & Keir, 2008 ).…”

“…The displacement of finger flexor tendons during finger motions happens in proximo-distal, radial-ulnar, and dorsal-palmar directions. Individual or multi-finger motions cause geometric displacement of the finger flexor tendons which leads to deformation of the median nerve ( Ugbolue et al, 2005 ; Canuto et al, 2006 ; Yoshii et al, 2008 ). In addition, intrusion of lumbrical muscles into carpal tunnel during forceful finger flexion may lead to median nerve deformation ( Cartwright et al, 2014 ).…”

Effects of grip force on median nerve deformation at different wrist angles

“…MRI studies have suggested that wrist flexion/extension can decrease the volume of the carpal tunnel when compared to neutral wrist postures ( Mogk & Keir, 2008 ; Mogk & Keir, 2009 ). Furthermore, wrist flexion and extension movements cause three-dimensional displacement of the median nerve and finger flexor tendons, namely proximal-distal, radial-ulnar, and dorsal-palmar displacements ( Canuto et al, 2006 ; Wang et al, 2014 ; Yoshii et al, 2008 ; Yoshii et al, 2013 ). Subsequently, changes in wrist posture and finger movements can also influence finger flexor tendons geometry within the carpal tunnel ( Keir & Wells, 1999 ; Martin et al, 2013 ).…”

A near infrared technique for tendon imaging in human hand

“…Theo một nghiên cứu cho thấy, chấn thương bàn tay chiếm 14% -30% các chấn thương trong các phòng cấp cứu, trong đó, chấn thương liên quan đến gân chiếm 29%, đứng thứ 2 so với các chấn thương liên quan đến bàn tay [1,2]. Sau khi khám lâm sàng, các phương pháp y học hỗ trợ chẩn đoán hiện đại hơn như siêu âm, chụp cắt lớp vi tính và chụp cộng hưởng từ đã được chứng minh là công cụ chẩn đoán quan trọng [3][4][5] [7,8], chẩn đoán của phù não [9,10] và cũng chụp nhũ ảnh [11,12]. Kỹ thuật này cũng được sử dụng để xác định hình ảnh tĩnh mạch [6,[10][11][12] hay để nghiên cứu hình ảnh lòng bàn tay [13].…”