Sanchez-Urgelles Pablo, Diez Sánchez Blanca, Sanchez-Sotelo Joaquin
Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
Upper Limb Surgery Unit, Orthopaedics and Traumatology Department, La Paz University Hospital, Madrid, Spain.
JSES Rev Rep Tech. 2025 Feb 28;5(2):170-181. doi: 10.1016/j.xrrt.2025.01.011. eCollection 2025 May.
Paralysis of the serratus anterior (SA) is most frequently caused by dysfunction of the long thoracic nerve (LTN). Although this condition presents with classic physical examination findings, it is occasionally missed. The purpose of this study is to review the etiology, diagnosis, and treatment options for SA palsy.
This study summarizes the anatomy of the SA and LTN, most common causes of SA palsy, physical examination findings, utility of diagnostic tests, the natural history of this condition, and all treatment options that can be contemplated.
SA palsy should be suspected in patients with weak forward flexion and abnormal prominence of the medial edge of the scapula with weakness in shoulder protraction. The diagnosis can be confirmed with electromyography and nerve conduction studies. Magnetic resonance may show neurogenic fatty infiltration or atrophy. Although most patients benefit from conservative treatment (mostly physical therapy) for the first 12 months, many patients experience persistent weakness with various degrees of severity. For patients with disabling symptoms, nerve release or transfers have been reported to lead to SA reinnervation with functional improvements. However, long-standing palsy is best managed with a split pectoralis major transfer of the sternal head to the inferior pole of the scapula. Scapulothoracic arthrodesis is an uncommon procedure for patients in whom a previous tendon transfer has failed.
LTN dysfunction leading to SA palsy can be typically diagnosed with certain physical examination findings and confirmed using electromyogram with nerve conduction studies. Although spontaneous recovery can occur, patients with persistent serratus weakness may be considered for neurolysis, nerve transfer, or tendon transfer. Currently, direct transfer of the sternal head of the pectoralis major to the inferior pole of the scapula is our management of choice for patients with disabling symptoms and no improvement despite a good program of physical therapy.
前锯肌（SA）麻痹最常见的原因是胸长神经（LTN）功能障碍。尽管这种情况在体格检查时有典型表现，但偶尔也会被漏诊。本研究的目的是回顾前锯肌麻痹的病因、诊断和治疗选择。
本研究总结了前锯肌和胸长神经的解剖结构、前锯肌麻痹的最常见原因、体格检查结果、诊断性检查的作用、这种情况的自然病程以及所有可考虑的治疗选择。
对于前屈无力且肩胛骨内侧缘异常突出伴肩外展无力的患者，应怀疑前锯肌麻痹。可通过肌电图和神经传导研究确诊。磁共振成像可能显示神经源性脂肪浸润或萎缩。尽管大多数患者在最初12个月受益于保守治疗（主要是物理治疗），但许多患者仍会出现不同程度的持续无力。对于有致残症状的患者，据报道神经松解或神经移位可导致前锯肌重新获得神经支配并改善功能。然而，对于长期麻痹，最好采用胸大肌胸骨头转移至肩胛骨下极的方法。肩胛胸壁关节固定术是一种用于先前肌腱转移失败患者的不常见手术。
导致前锯肌麻痹的胸长神经功能障碍通常可通过特定的体格检查结果诊断，并通过肌电图和神经传导研究确诊。尽管可能会自发恢复，但对于持续存在前锯肌无力的患者，可考虑进行神经松解、神经移位或肌腱转移。目前，对于有致残症状且尽管进行了良好的物理治疗方案仍无改善的患者，我们首选的治疗方法是将胸大肌胸骨头直接转移至肩胛骨下极。
