Injuries to the adductor longus commonly occur in the proximal part of the muscle tendon unit, close to the insertion site on the pubic bone. Ultrasonography, magnetic resonance imaging (MRI) and surgery have been helpful in localising the lesions, but the exact anatomy of the musculotendinous junction (MTJ) and insertion of the muscle remain unclear. We studied the anatomical features of the MTJ and measured the dimensions of the tendinous insertion into the pubic bone on 37 cadavers: 18 men and 19 women. The medial boundaries were the longest part of the tendon bilaterally in women, while the lateral aspect of the left muscle was greater in men. Tendinous fibres were predominantly found on the anterior surface, while the posterior surface consisted mainly of muscle tissue. The MTJ was clearly demarcated. There were several types of anomalies present which partially explains the difficulty in localising the site of injury and highlights the importance of individualized treatment.