应用多层螺旋CT观察胸骨肌的发生率和解剖特点

Incidence and anatomical features of sternalis muscle with multidetector computed tomography

目的：采用多层螺旋CT（MDCT）研究普通人群中胸骨肌的出现率及解剖特点.方法：回顾性分析5000例无前胸壁疾患成人胸部MDCT轴位图像,统计胸骨肌出现率,单、双侧出现率及性别差异,并进一步分析其位置,形态,起、止及大小等解剖特点.结果：5000例成人中胸骨肌出现率为5.8%,男性（6.7%）高于女性（4.3%）.单、双侧分别为195、95例.单侧195例中左、右侧分别为71例、124例,单、双侧出现率男女性别差异无统计学意义.在CT轴位上胸骨肌位于胸骨两侧,胸大肌浅面,其断面呈扁平状或结节状,重建图上呈上下纵向走行扁梭形或条带状,部分可呈内上向外下走行.胸骨肌上缘起自第5肋软骨水平以上,附着于肋软骨、胸大肌、胸骨柄及体部、胸锁乳突肌肌腱,下缘止于第3～7肋软骨水平,附着于腹外斜肌腱、胸肌筋膜、肋软骨、胸骨体及剑突.胸骨肌形态变异大,平均长度（7.01±2.69）cm,平均厚度（0 50±0.20）cm,平均宽度（2.10±1.21）cm.结论：胸骨肌在正常人群中有较高出现率,MDCT轴位与三维重建结合能很好地显示其解剖特点.

Objective：To analyze the incidence and anatomical features of the sternalis muscles with multidetector computed tomography （MDCT）. Methods： The axial MDCT chest images of 5 000 adults without abnormal anterior chest wall were retrospectively investigated to find out the overall and gender frequency of the sternalis muscles. The frequency of unilateral or bilateral appearance, anatomical features including size, shape, location and attachment were also analyzed. Results： The sternalis muscle was present in 290 （5.8%） of the 5 000 adults. This muscle was more common in male （6.7%） than in female （4. 3%） adults with statistical significance. While distribution of unilateral or bilateral side in different gender had not statistically significance. Ninty-five adults （32.8%） showed bilateral sternalis muscles. Among 195 adults with unilateral sternalis muscles, 124 patients showed right sternalis muscles and 71 patients showed the left ones. The sternalis muscles on CT axial transverse images showed flat shape or nodular appearance superficial to major pectoral muscle. CT reconstruction images showed the muscles ran from the infra-clavicular regions to approximately the caudal aspect of the sternum with a parallel or oblique course to the sternum. The size of sternalis muscle was significantly variable. The average height, anteroposterior diameter and width were （7. 01 ±2.69）cm, （0. 50±0. 20）cm and （2.10±1.21）cm respectively. Conclusion： The sternalis muscle has a high incidence in normal adults. MDCT is an effective method to demonstrate this muscle in vivo.