Latissimus dorsi and teres major tendons: separate or conjoint tendons?

Latissimus dorsi and teres major are used for tendon transfer about the shoulder in treating weakness that results from brachial plexus palsy. Anatomy textbooks describe separate insertion sites for these two tendons. During a surgical procedure, which included releasing these two tendons off the humerus from a posterior approach, they appeared to be joined together. Cadaver shoulders were subsequently dissected to determine if the tendons had conjoint or separate insertions. We found that although the two tendons do have separate insertion sites, they were joined to one another and difficult to separate. For this reason, when performing releases or transfers with these muscles, surgeons should consider the two as one structure in order to avoid damage to the important surrounding neurovascular structures (axillary and radial nerves, posterior humeral circumflex artery).