Morphological Variation of the Soleus Muscle: Determining General Patterns and Characteristics of the Connective Tissue Architecture Project ID: 000533526 Public

4 Media · 1 Specimen · Creator: Keanna G Theobalt · Managed by: KEANNA THEOBALT

Introduction: Injuries to the calf muscle complex require accurate identification of anatomical structures to reassure proper prognostic outcomes including recovery timeframes and treatment responses. Soleus strains commonly involve the myotendinous (MTJ) or myofascial (MFJ) junctions, but due to the complexity of the muscle itself, little is known about these connective tissue architectures. This study aims at identifying variations in the soleus’ tendinous structures as a starting point to understanding the distribution of connective tissue and its relationship to injury susceptibility and further anatomical classification. Methods: Forty (n=40) soleus muscles, representing both left and right sides from twenty (n=20) formalin-embalmed cadavers (average age 78 years old; 10 males, 10 females) were dissected in-situ and then removed for measurements of connective tissues. Muscles were cut in cross-section at three locations: proximal, middle, and distal, to follow, measure, and compare each MTJ and MFJ through the course of the muscle. The anterior surfaces were subsequently visualized and reconstructed in three dimensions using an Artec Space Spider. Results: The lateral connective tissue components displayed a more consistent pattern when determining relationships to the lateral portion of the anterior aponeurosis compared to the medial side, at each location. On average, the lateral intramuscular tendon (iLOT) decreased in size from proximal to distal; however, the medial intramuscular tendon (iMOT) was widest at the middle location. At the proximal and middle locations, there was a statistically significant positive correlation between the iLOT and the total width of the lateral anterior aponeurosis. In contrast, the medial compartment displayed a statistically significant positive correlation between the medial origin tendon and the total width of the medial anterior aponeurosis. Discussion: Most injuries tend to occur at the either the MTJ or MFJ therefore knowledge of the connective tissue architecture is useful to identify different patterns of injury. Understanding the variations of these connective tissues at multiple locations will allow for more accurate regional diagnosis of the soleus on imaging and better determination of adequate courses of treatment.