Determination of entry point
The nail insertion site lies on the axis of the humeral shaft. It is located at the bone-cartilage junction of the humeral head. It is not more lateral on the greater tuberosity. Therefore, a supraspinatus split is necessary.
It is slightly anterior to the center of the greater tuberosity.
Be aware, that the correct entry point depends on the type and design of nail used.
Insert a K-wire through the correct entry point and confirm proper placement by image intensification.
Open the humerus
A cannulated awl is recommended for opening the proximal humerus. This awl can be inserted over the previously placed guide wire. It should be advanced into the proximal medullary canal.
Pitfall: hidden entry point
If the humeral head is abducted or externally rotated, the entry point is under the acromion. This is typical with varus malaligned fractures.
One has to reduce the humeral head before opening the humeral entry point. A joy-stick technique, as illustrated, is helpful. Alternatively, sutures though the rotor cuff can be used in order to manipulate the humeral head.