Casteel Andrew T, McNees Braden R, Iwanaga Joe, Tubbs R Shane, Hill Steven M
Neurosurgery, Tulane University School of Medicine, New Orleans, USA.
Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, USA.
Cureus. 2025 Jul 25;17(7):e88743. doi: 10.7759/cureus.88743. eCollection 2025 Jul.
The anconeus epitrochlearis muscle (AEM) is an anatomical variant found in various animal species and some humans, believed to be evolutionarily linked to climbing behavior. It typically spans from the medial epicondyle of the humerus to the olecranon and is innervated by the ulnar nerve. While most AEMs appear as a single-headed muscle, this case report describes a rare three-headed AEM identified during routine cadaveric dissection of an 82-year-old female. On the right side, the AEM showed a typical single-headed structure. On the left side, however, the muscle had three distinct heads, with the proximal head located deep to the ulnar nerve, an unusual configuration not previously documented. All measurements were made using microcalipers. Clinically, the AEM has been associated with cubital tunnel syndrome due to potential ulnar nerve compression. However, some studies suggest it might protect the ulnar nerve compared to the more rigid Osborne's ligament. Variants of the AEM are rare, and to our knowledge, this case of a three-headed AEM is likely the first such report in the literature, contributing new anatomical knowledge with potential clinical relevance.
肱三头肌内侧头（AEM）是在各种动物物种和一些人类中发现的一种解剖变异，据信在进化上与攀爬行为有关。它通常从肱骨内上髁延伸至鹰嘴，并由尺神经支配。虽然大多数AEM表现为单头肌，但本病例报告描述了在一名82岁女性的常规尸体解剖中发现的罕见三头AEM。右侧的AEM呈现典型的单头肌结构。然而，左侧的肌肉有三个明显的头，近端头位于尺神经深部，这种异常构型此前未有记录。所有测量均使用微型卡尺。临床上，AEM因可能压迫尺神经而与肘管综合征有关。然而，一些研究表明，与更坚韧的奥斯本韧带相比，它可能会保护尺神经。AEM的变异很少见，据我们所知，这种三头AEM病例可能是文献中首例此类报告，为具有潜在临床相关性的新解剖学知识做出了贡献。
