Brachialis insertion measurement: an anatomic cadaver study for plate fixation of the coronoid process fracture.

Detailed assessment of the proximity of the brachialis insertion to the anterior bundle of the medial collateral ligament and its potential influence on plate application for the treatment of the coronoid process fracture has not been reported previously. The purpose of this study was to describe the anatomic interval used for coronoid plate and the measurement of the brachialis insertion to confirm partial release of the insertion site may be required during plate fixation of the coronoid process fracture. After eight fresh-frozen cadaveric elbows were dissected, the interval between the brachialis insertion and the attachment of the anterior bundle of medial collateral ligament was identified, and the gross morphological characteristics of the brachialis insertion were also recorded. The average width of the interval was 4.14 mm, and the brachialis was found to be consisted of a superficial head and a deep head, and insertion of the deep head was composed of three units: a medial aponeurosis, a lateral aponeurosis, and muscle fibers inserted directly into the ulna. The interval between the brachialis insertion and the attachment of the anterior bundle of medial collateral ligament can be used for placement of the coronoid plate regardless of the plate type. Partial release of the brachialis insertion is necessary during the operation, while the width of the plate is larger than that of the interval. This study may provide some useful information on plate application for the treatment of the coronoid process fracture.