Novakov Stoyan S, Yotova Nina I, Petleshkova Tsvetanka D, Muletarov Spas M
Department of Anatomy, Histology and Embryology, Medical University, Plovdiv, Bulgaria.
Folia Med (Plovdiv). 2008 Apr-Jun;50(2):63-6.
One important variant of the panniculus carnosus remnants--a superficial muscle layer in the thoracic region typical for lower mammals, is an often found variation known by the name of sternalis muscle. It was discovered for the first time by Cabrolius in 1604 and identified precisely in 1726 by Du Puy. Even today, the variation is still an object of description and attempted to be classified and defined. We found an abnormal muscle band known as sternalis muscle (m. sternalis). The variation was accompanied by a partial bilateral agenesia of the pars sternocostalis of the pectoralis major muscle. Although m. sternalis was first described 3 centuries ago, its origin is still unclear. Some authors suggest that it originates from adjacent muscles such as the sternocleidomastoid muscle, pectoralis major muscle, rectus abdominis muscle, etc. Kadanov considers the muscle a remnant of panniculus carnosus, a muscle layer located immediately under the skin in lower mammals. Our case confirms the hypothesis of the pectoral origin of m. sternalis. It is not only a rare variation of interest to morphologists, but also a structure which is important for clinicians. The location of the muscle makes it essential for general and plastic surgeons as well as for the specialists in imaging diagnostics. In conclusion we consider that this anomaly belongs to the group of the rudimentary structures in human beings, which appear to be more variable. The suggestion of its development as a possible phylogenic regularity in the evolution makes it all the more important for the morphological science and medical practice.
腹直肌残余的一个重要变体——一种在胸部区域存在的、对低等哺乳动物而言典型的浅表肌肉层，是一种常被发现的变异，名为胸骨肌。它于1604年首次被卡布罗利乌斯发现，并于1726年由迪皮精确识别。即便在今天，这种变异仍是描述的对象，并试图对其进行分类和定义。我们发现了一条被称为胸骨肌（m. sternalis）的异常肌带。这种变异伴有胸大肌胸肋部的部分双侧发育不全。尽管胸骨肌在3个世纪前就首次被描述，但其起源仍不清楚。一些作者认为它起源于相邻肌肉，如胸锁乳突肌、胸大肌、腹直肌等。卡达诺夫认为该肌肉是腹直肌的残余，腹直肌是低等哺乳动物中紧邻皮肤下方的一层肌肉。我们的病例证实了胸骨肌起源于胸部的假说。它不仅是形态学家感兴趣的一种罕见变异，也是对临床医生而言很重要的一种结构。该肌肉的位置对普通外科医生、整形外科医生以及影像诊断专家来说都至关重要。总之，我们认为这种异常属于人类中发育不全结构的范畴，这类结构似乎更具变异性。其作为进化中一种可能的系统发育规律的发育假说，使其对形态科学和医学实践而言更加重要。
