Anatomical characteristics of the tibialis anterior tendon and clinical significance.

purposeTo describe the anatomical characteristics of the tibialis anterior tendon (TAT), and thereby to provide a reference for the precise anatomy of structures surrounding the ankle joint and the surgical repair of tendon-related injuries.

methodsA total of 100 human lower limbs were prepared and the tibialis anterior muscles (TAMs) were dissected. All anatomical specimens were perfused and preserved with 10% formalin solution, and the specimens were unpaired samples. The lengths of the TAT and muscle belly, the thickness and width of TAT at its insertion, as well as the thickness and width of the muscle-tendon junction (MTJ) were measured. Statistical analyses were performed using Fisher's exact test, analysis of variance (ANOVA), and independent-samples t test, with P < 0.05 considered statistically significant.

results(1) The TAT was classified into the following types: Type I: the TAT consisted of two bundles of equal size; the anterior bundle inserted into the base of the first metatarsal bone and the posterior bundle into the medial cuneiform bone in 27 cases (27%). Type II: the TAT consisted of two bundles of unequal size; the larger portion inserted into the medial cuneiform bone and the smaller portion into the base of the first metatarsal bone in 55 cases (55%). Type III: The TAT consisted of two bundles of unequal size; the smaller portion inserted into the medial cuneiform bone and the larger portion into the base of the first metatarsal bone in 14 cases (14%). Type IV: The TAT consisted of deep and superficial layers; both of them inserted to the medial cuneiform and the base of the first metatarsal bones in 1 case (1%). Type V: the TAT consisted of two bundles of unequal size; the anterior bundle inserted into the mid-anterior portion of the first metatarsal bone, and the posterior bundle into the medial cuneiform bone and the first metatarsal bone in 2 cases (2%). Type VI: The TAT consisted of deep, middle and superficial layers; the superficial layer inserted into the base of the first metatarsal bone and the medial cuneiform bone, the middle layer into the base of the first metatarsal bone, and the deep layer into the medial cuneiform bone in 1 case (1%) (2) The width and thickness of the TAT at the insertion were 12.97 ± 4.45 mm and 1.91 ± 0.51 mm. There was a significant difference in the width of TAT insertion in the types of I~Ⅲ (P < 0.05). There was a significant difference in the muscle belly length of TAM between male and female (P < 0.05).

conclusionThe classification of TAT in this study complements the detailed anatomy of the ankle joint. Understanding the characteristics and variations of TAT aids in comprehending the mechanisms of foot and ankle injuries and provides important information for their diagnosis and treatment.