Morphological Variability of the Thigh Muscle Traps in an Ultrasound That Awaits Clinicians

Abstract

Objectives: Muscles and their tendons present a considerable diversity of morphological variations. The aim of this study was to explore variants of muscles and tendons from compartments of the thigh and to raise awareness about potential problems during ultrasound examination. Materials and Methods: This comprehensive review of the literature was created on the basis of scientific articles sourced from PubMed. The search included all relevant papers related to the topic, ensuring that the most up-to-date studies were incorporated. In order to achieve these results, we created the exclusion criteria and extracted papers that did not meet the requirements of our review. Relevant papers were incorporated, and tracking of citations was fulfilled. The described method allowed for a broad yet detailed understanding, ensuring that the review of the literature covers all key aspects of the presented research. Results: Various aspects of thigh muscle anomalies were already undertaken; however, as this study has shown, current knowledge, while valuable, is insufficient to draw definitive conclusions regarding the prevalence and clinical implications of these muscle variations. A more robust body of ultrasound-based research is essential to accurately characterize these anomalies, establish their frequency, and assess their impact on clinical decision-making, including diagnostic accuracy, surgical planning, and therapeutic interventions. Conclusions: Numerous anatomical variations of the thigh muscles and tendons that were described in literature over the years might have clinical implications and could lead to mistakes during diagnosis by ultrasound imaging.

Keywords: adductor muscles; biceps femoris; imaging study; morphological variations; quadriceps femoris; sartorius; semimembranosus; semitendinosus; tensor fasciae suralis; tensor of the vastus intermedius; ultrasound.

Figure 4

Type IIID of the QF by Olewnik et al. [25]. SVL: superficial part of the vastus lateralis. IVL: intermediate part of the vastus lateralis. VI: vastus intermedius. VM: vastus medialis. 5: fifth head. 6: sixth head. 7: seventh head. 8: eighth head.

Figure 1

Schematic summary of the method used during preparation of the presented review of the literature.

Figure 2

Schematic representation of the variable sartorius muscle reported by Kim et al. [7]. ASIS: anterior superior iliac spine. SM: sartorius muscle. L: lateral head of the sartorius muscle. M: medial head of the sartorius muscle. Ac: accessory sartorius muscle.

Figure 3

Typical position of the TVI. TVI tensor of the vastus intermedius. SVL: superficial part of the vastus lateralis. IVL: intermediate part of the vastus lateralis. VI: vastus intermedius. VM: vastus medialis.

Figure 5

Schematic presentation of the variable pectineus muscle presented by Kim et al. [37]. The tendon of the superficial layer is indicated by an asterisk (*). PM: pectineus muscle. AL: adductor longus muscle. IP: iliopsoas muscle. SM: sartorius muscle. FV: femoral vein. FA: femoral artery. DFA: deep femoral artery. DFV: deep femoral vein. FN: femoral nerve. (*) the tendon of the superficial layer.

Figure 6

Variation of Pes Anserinus by Olewnik et al. [47]. IhVM: lateral head of the vastus lateralis. mhVM: medial head of the vastus medialis. RF: rectus femoris muscle. P: patella. PT: patellar tendon. S: sartorius muscle. ST: semitendinosus tendon. G: gracilis muscle. GT: gracilis tendon. STM: semitendinosus muscle. GM: gastrocnemius muscle. abSTT: accessory band of the semitendinosus tendon. SM: soleus muscle. fSM: fascia of the soleus muscle.

Figure 7

Schematic presentation of a fusion between semitendinosus muscle and long head of biceps femoris. ST: semitendinosus muscle. BFL: long head of biceps femoris. SM: semimembranosus muscle. (*) fusion between BFL and SM.

Figure 8

Schematic presentation of the tensor fasciae suralis reported by Olewnik et al. [2]. TFS: tensor fascia suralis. PS: popliteal surface of the femur. DF: deep fascia.