George Christopher Nomikos MD, Abstract Co-Author: Nothing to Disclose

Mark E. Schweitzer MD, Abstract Co-Author: Nothing to Disclose

Laith Jazwari MD, Abstract Co-Author: Nothing to Disclose

Patricia Martina Cunningham MBBCH, Presenter: Nothing to Disclose

Wolff's law states that bone hypertrophies in response to stress. Classically, this hypertrophy is thought to occur from gravitational stress, which is fairly constant. This increases occurs primarily in trabecular bone. We hypothesized that the intermittent stress of pitching would result in perceptable changes in humeral cortical thickness.

Eleven varsity baseball pitchers were evaluated. Axial T2 weighted images through each distal humerus were evaluated for cortical thickness, blinded to whether it was the pitching or non-pitching arm. Measurements were obtianed 4 images proximal to the first image on which the tip of the olecranon was visible. The number of innings pitched over each subject's career was also obtained. The T-test was used to compare the pitching to the non-pitching arm.

Cortical thickness ranged from 2 to 6 mm (mean 3.5 mm). The range was 3-6 mm in the pitching arm and 2-5 mm in the non-pitching arm. In only one subject was the cortex thicker in the non-pitching humerus (p=0.009).

Baseball pitching leads to visible cortical hypertrophy in the humerus.

Nomikos, G, Schweitzer, M, Jazwari, L, Cunningham, P, Upper Extremity Stress Changes in the Throwing Athlete.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4417254.html