Service d'orthopédie et traumatologie pédiatrique (Pr P.-Journeau), hôpital d'enfants de Brabois, CHU de Nancy, Nancy, France.
Orthop Traumatol Surg Res. 2013 Sep;99(5):543-7. doi: 10.1016/j.otsr.2013.04.002. Epub 2013 Aug 2.
Various studies have found that 6.6 to 31% of supracondylar elbow fractures in children have nerve-related complications. One-third of these are cases of anterior interosseous nerve (AIN) palsy that usually result in a deficit of active thumb and index flexion. The goal of this cadaver study was to describe the course of the AIN to achieve a better understanding of how it may get injured.
On 35 cadaver specimens, the median nerve and its collateral branches destined to muscles were dissected at the elbow and forearm levels. The distance at which the various branches arose was measured relative to the humeral intercondylar line. Interfascicular dissection of the AIN was used to map its distribution within the median nerve.
The AIN arises at an average of 45 mm from the humeral intercondylar line. Before emerging from the median nerve, the AIN fascicles were always found in the dorsal part of the median nerve. After emerging, the AIN was divided into two zones. Zone 1 was the transitional portion from its exit point until its entrance into the interosseous space, where it changes direction. Zone 2 was the interosseous portion between the radius and ulna that comes into contact with the anterior interosseous membrane to which it is attached over its entire length until it ends in the pronator quadratus (PQ) muscle. The muscle branches of the AIN destined for the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) muscles mostly originated in Zone 1, which is the transitional portion between the median nerve and the fixed Zone 2. The branches destined to the pronator teres (PT) and flexor carpi radialis (FCR) originating from the median nerve are more proximal and superficial.
The injury mechanisms leading to selective AIN palsy secondary to supracondylar elbow fracture in children are probably the result of two factors: direct contusion of the posterior aspect of the median nerve, and thereby the AIN fascicles, by the proximal fragment; stretching of AIN in Zone 1, which has less ability to withstand stretching than the median nerve and its other branches because the AIN is fixed in Zone 2.
Details about the origin and course of the AIN can explain the high percentage of AIN palsy in supracondylar elbow fractures in children.
Level IV. Anatomic study.
多项研究发现，儿童髁上肘骨折中有 6.6%至 31%与神经相关并发症。其中三分之一为正中神经骨间前神经（AIN）麻痹，通常导致拇指和食指主动屈曲功能丧失。本尸体研究旨在描述 AIN 的走行，以更好地理解其受伤机制。
在 35 具尸体标本上，在肘部和前臂水平解剖正中神经及其向肌肉发出的侧支。测量各个分支与肱骨髁间线的距离。使用束间解剖法描绘 AIN 在正中神经内的分布。
AIN 平均距离肱骨髁间线 45mm 处发出。在从中正神经发出之前，AIN 束总是位于正中神经的背侧。穿出后，AIN 分为两个区。第 1 区为从中止点到进入骨间空间的过渡区，在此处改变方向。第 2 区为桡骨和尺骨之间的骨间部分，与附着于全长的前骨间膜接触，止于旋前方肌（PQ）。支配拇长屈肌（FPL）和指深屈肌（FDP）的 AIN 肌支主要发自第 1 区，即正中神经和固定的第 2 区之间的过渡区。发自正中神经的支配旋前圆肌（PT）和桡侧腕屈肌（FCR）的分支更靠近近端和表浅。
儿童髁上肘骨折导致选择性 AIN 麻痹的损伤机制可能是两个因素的结果：近端骨折块直接挫伤正中神经及其 AIN 束；在 AIN 固定于第 2 区的情况下，第 1 区的 AIN 拉伸，该区伸展能力较正中神经及其其他分支差。
AIN 的起源和走行的细节可以解释儿童髁上肘骨折中 AIN 麻痹的高比例。
IV 级。解剖学研究。
