Pectoralis Major Tendon as Landmark for Proximal Humerus Surgery: A Cadaveric Study on the Adult Filipino Population

Abstract

Objective. It is common to get lost during a comminuted proximal humerus surgery, and the pectoralis major insertion is always a constant. Therefore, this study aimed to do a cadaveric study on the Filipino population to assess the distance from the pectoralis major tendon to the top of the humeral head (PMT) as a reference during proximal humerus surgery.

Methods. This study dissected the shoulders of cadavers. The distance from the pectoralis major tendon insertion to the top of the humeral head (PMT) was measured using a caliper. This PMT distance was also correlated to the cadaver's height and sex.

Results. This study dissected 110 shoulders (55 cadavers | 24 females, 31 males). The median PMT was 5.40 cm for males and 4.90 cm for females, with a combined value of 5.40 cm overall. There was a direct and moderate correlation between the PMT with overall height. Height and PMT of both the left and right shoulder were significantly longer among males compared to females. The study showed that for every centimeter increase in the height of males, there was a corresponding 0.02 cm increase in the PMT, adding the constant factor of 1.83. A corresponding 0.04 cm increase in the PMT for females added the constant factor of -0.81.

Conclusion. The pectoralis major tendon insertion is a consistent landmark that can accurately restore humeral length when reconstructing complex proximal humerus fractures where landmarks are otherwise lost because of comminution.