因背包引起神經麻痺之生物力學研究

田文政

《體育學報》 9期 (1987/12) Pp. 201-211

https://doi.org/10.6222/pej.0009.198712.1613

摘要

目前對因背包引起神經麻痺症狀，認為是由於手臂神經叢或胸部長形神經受到壓迫及牽引過度所致。然而，對其正確之架構尚未完全廓清，在本研究中，試就背包所引起的神經麻痺之力學基礎加以解釋。為了瞭解這種現象，進行了一項實驗，希望達到：(1)借助X光射線分析背包肩帶之確實位置。(2)測量背包肩帶下方之承受壓力。(3)對受壓迫區域之神經束做解剖學上的分析研究。
經研究結果發現，在休止狀態中肩帶內側之邊緣，從鎖骨之中心部移至肋骨之旁側，最後向下移至腋窩內部。然而在運動中，肩帶內側之邊緣移至鎖骨側面，而肩帶之中央部份則移至肩胛骨之肩峯和肱骨之頭部。因此，背負背包行走時，肩帶都在肩部區域之內移動，而且，肩胛骨在背負背包行走時會向身體正中間位移。
在受壓實驗中發現：(1)最大的負荷係落在身體軀幹之上，亦卽上肩胛部位和鎖骨部位。(2)肩帶之內側邊緣部份較其中心部份產生更強的壓力。
依解剖學上分析，顯示肌肉承受壓力過高或身體表面承受壓力情況下，手臂神經叢會受到強大壓力。
根據以上研究結果，手臂神經麻痺係由於背包之荷重形成一種牽引性外力，作用於鎖骨和頸部神經上，它並且成為一股外力作用於從喙突至腋下神經。另外，長形胸神經麻痺是由於第二肋骨之鋸肌前方神經受到壓迫與牽引所致。

並列摘要

The rucksack paralysis is currently considered to be caused by the compression or hypertraction of brachical plexus or long thoracic nerve. However, its precise mechanism has not yet been fully clarified. In the present study, we attempted to explain the mechanisms of rucksack paralysis. For this purpose, three sets of studies were performed:
(1)examinations on the exact localization of shoulder straps with the aid of radiographic analysis (2)measurements of the compression under the straps with load cell, and (3)an-atomical studies on the nerve pathway under the compressed area.
In the experimental subjects, the inside edge of the strap at rest was found to run from area around the center of clavicle to the lateral side of the ribs. Finally, it went down to the inner part of the exilla. However, on tread-mill walking the position of inside edge of strap shifted to the lateral part of the clavicle and the central part of it moved to both the acromion of the scapula and the head of the humerus. Thus, during the actual walking with rucksack, the strap was considered to move within these areas. In addition, we found that carrying a rucksack displaced the scapulae toward the median.
From the measurements of the compression under the strap subjects, we found(1)the heaviest load was upon the upper part of the body trunk, i. e. supra scapular region and clavicular region, and(2)the edge of the strap produced stronger compression than its center did.
Anatomical studies the brachial plexus might be strongly compressed in the case of muscular hypertonicity or body surface compression.
From these results, the paralysis of the brachial plexus is caused by the load of rucksack working as a tractive external force on the nerves between the clavicle and neck, while it acts as a compressive external force on the nerves from coracoid processes to the axillary region. On the other hand, the paralysis of the long thoracic nerve seems to occur due to hyper traction of or compression over the tuberosity of the serratus anterior muscle of the second rib.