Department of Cell Biology and Human Anatomy, University of California, School of Medicine, Davis, California, United States.
Folia Morphol (Warsz). 2023;82(4):957-962. doi: 10.5603/FM.a2022.0109. Epub 2022 Dec 27.
Accessory thoracic muscles in humans are relatively common and it is important to draw awareness to their variable presentations and potential clinical implications owing to their close association with the axilla. Here we report four cases of accessory thoracic muscle variations identified in the ethnically diverse whole- -body donation population in Northern California (4 out of 48 donors, 8.3%). Of these, combined presentations of thoracic accessory muscles were observed in two of the donors, one involving bilateral axillary arches and a pectoralis quartus on the left and the other a unilateral axillary arch on the left and bilateral pairs of pectoral fascicles. In the former, the proximal ends of the left axillary arch and pectoralis quartus joined to form a common aponeurosis which inserted onto the deep tendon of the pectoralis major; in the latter, the pectoral fascicles originated from the surface of the ribs and inserted into the deep surface of the pectoralis major muscle. In the other two donors, unilateral axillary arches were observed. Our observations illustrate that accessory thoracic muscles, in isolated as well as combined forms, are commonplace in the general population. We also describe the proposed embryonic origins of these accessory muscles, which may reflect their frequent occurrence, and potential clinical implications of these muscles, as discussed in literature.
人类的辅助性胸肌较为常见，由于其与腋窝密切相关，因此需要注意其不同的表现形式及其潜在的临床意义。在此，我们报告了在加利福尼亚北部的种族多样化的整体捐赠人群中发现的 4 例辅助性胸肌变异（48 名捐赠者中的 4 例，占 8.3%）。其中，有 2 名捐赠者表现出了胸肌辅助肌的联合表现，一例是左侧腋弓和胸小四头肌双侧存在，另一例是左侧腋弓单侧存在，双侧存在胸肌束。在前一例中，左侧腋弓和胸小四头肌的近端连接形成一条共同的腱膜，插入到胸大肌的深部肌腱；在后一例中，胸肌束起源于肋骨表面，插入胸大肌的深部表面。在另外 2 名捐赠者中，观察到单侧腋弓。我们的观察结果表明，辅助性胸肌，无论是单独存在还是联合存在，在普通人群中都很常见。我们还描述了这些辅助性肌肉的胚胎起源，这可能反映了它们的频繁发生，以及文献中讨论的这些肌肉的潜在临床意义。
