Anatomic factors related to the cause of tennis elbow.
BACKGROUND
The pathogenesis of lateral epicondylitis remains unclear. Our purpose was to study the anatomy of the lateral aspect of the elbow under static and dynamic conditions in order to identify bone-to-tendon and tendon-to-tendon contact or rubbing that might cause abrasion of the tissues.


METHODS
Eighty-five cadaveric elbows were examined to determine details related to the bone structure and musculotendinous origins. We identified the relative positions of the musculotendinous units and the underlying bone when the elbow was in different degrees of flexion. We also recorded the contact between the extensor carpi radialis brevis and the lateral edge of the capitellum as elbow motion occurred, and we sought to identify the areas of the capitellum and extensor carpi radialis brevis where contact occurs.


RESULTS
The average site of origin of the extensor carpi radialis brevis on the humerus lay slightly medial and superior to the outer edge of the capitellum. As the elbow was extended, the undersurface of the extensor carpi radialis brevis rubbed against the lateral edge of the capitellum while the extensor carpi radialis longus compressed the brevis against the underlying bone.


CONCLUSIONS
The extensor carpi radialis brevis tendon has a unique anatomic location that makes its undersurface vulnerable to contact and abrasion against the lateral edge of the capitellum during elbow motion.
Bunata
Robert E
RE
John Peter Smith Affiliated Orthopedic Residency Program, University of North Texas Health Science Center, Fort Worth, TX 76109, USA. rbunata@hsc.unt.edu
Brown
David S
DS
Capelo
Roderick
R
D001696:Biomechanical Phenomena; D002102:Cadaver; D004396:Coloring Agents; D004551:Elbow Joint / Q000473:pathology*; D006801:Humans; D006811:Humerus / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D011403:Pronation / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D013484:Supination / Q000502:physiology; D013710:Tendons / Q000473:pathology*; D013716:Tennis Elbow / Q000209:etiology*
D004396:Coloring Agents