The Long Head of the Biceps Myotendinous Junction Is Located 1.14 Centimeters Distal to the Proximal Border of the Pectoralis Major Tendon: An Anatomic Study

To describe the proportional anatomic relationship of the long head of the biceps tendon (LHBT) myotendinous junction (MTJ) to pectoralis major tendon (PMT) and to provide an up-to-date review of the current literature. Ten fresh frozen cadaveric specimens were used. A deltopectoral approach was used for exposure and anatomical location of the MTJ as well as the proximal and distal borders of the PMT were identified by 2 fellowship-trained shoulder and elbow surgeons. The longitudinal length of the PMT, the distance from the long head of the biceps (LHB) MTJ to the proximal border of the PMT (pMTJ), and the distance from the LHB MTJ to the distal border of the PMT (dMTJ) were recorded. The relationship between the pMTJ and the PMT length was then reported as a ratio. The PMT was found to have a length of 5.16 ± 0.64 cm (4.1-6.1 cm). The pMTJ was 1.14 ± 0.52 cm (0.5-1.9 cm), and the dMTJ was 4.02 ± 0.91 cm (2.5-5.3 cm). The pMTJ/PMT ratio was 0.23 ± 0.11 (0.10-0.39). We found the average length of the PMT footprint to be 5.16 cm with the LHB MTJ beginning 1.14 cm distal to its proximal border. It is important to understand the LHBT and its relationship to surgically relevant surrounding anatomy to allow for appropriate tensioning and improved patient outcomes in the treatment of LHBT shoulder pathology.