Department of Morphology, Biosciences Center, Laboratory of Anatomy, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
Department of Morphology, Biosciences Center, Laboratory of Anatomy, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
Morphologie. 2024 Mar;108(360):100609. doi: 10.1016/j.morpho.2023.100609. Epub 2023 Oct 26.
The quadriceps femoris muscle is present in the anterior region of the thigh and is classically described as a muscle with four heads: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. A few years ago, a "fifth head" was described and named the tensor of the vastus intermedius (TVI). The TVI belly is in line with the belly of the vastus lateralis, and its aponeurosis imposes considerable tension on the vastus intermedius, medializing its action, to play a significant role in knee extension.
To perform a study of the TVI incidence in a Brazilian population and describe its variations.
We dissected lower limbs from cadavers previously fixed in 10% formaldehyde, belonging to the Laboratory of Anatomy of the Department of Morphology of the Biosciences Center of the Federal University of Rio Grande do Norte.
Eighty-one lower limbs were analyzed with only 33 (40.74%) of them presenting TVI. All four types of TVI described by the literature were present in our sample with the following distribution: type 1 with 15.15%; type 2 with 9.1%; type 3 with 33.33%; type 4 with 42.42%.
Although the literature points to the TVI as a normal belly of the quadriceps, making it a "quinticeps", our analysis points to the TVI as a variation and probably a matter of regionality. However, the presence of TVI is not a rare case and cannot be disregarded, which makes this study important for anatomists, physiotherapists, physicians, and surgeons.
股四头肌位于大腿前区，经典地描述为具有四个头的肌肉：股直肌、股外侧肌、股内侧肌和股中间肌。几年前，描述并命名了股中间肌的“第五个头”——股中间肌肌腹（TVI）。TVI 肌腹与股外侧肌的肌腹在一条线上，其腱膜对股中间肌施加相当大的张力，使其向内侧化，在膝关节伸展中发挥重要作用。
在巴西人群中进行 TVI 发生率的研究，并描述其变异。
我们解剖了来自先前用 10%甲醛固定的尸体的下肢，这些尸体属于联邦大学北里奥格兰德州生物科学中心形态学系解剖实验室。
我们分析了 81 条下肢，只有 33 条（40.74%）下肢存在 TVI。我们的样本中存在文献中描述的所有四种类型的 TVI，分布如下：1 型 15.15%；2 型 9.1%；3 型 33.33%；4 型 42.42%。
尽管文献指出 TVI 是股四头肌的正常肌腹，使其成为“五头肌”，但我们的分析表明 TVI 是一种变异，可能是区域性的。然而，TVI 的存在并不是一个罕见的情况，不能被忽视，这使得这项研究对解剖学家、物理治疗师、医生和外科医生都很重要。
