- Above the Level of the Pectoralis:
- frx above level of pectoralis allows proximal frag to abduct & rotate internally, owing to action of rotator cuff;
- pectoralis has greatest influence on shaft segment & tends to displace it medially and anteriorly;
- Above the Deltoid:
- deltoid pulls the lower fragment outward, while the pectoralis major, Latissimus, & Teres Major pull proximal fragment inward;
- supraspinatus, infraspinatus, and teres minor each insert on greater tuberosity, and externally rotate the humeral head
- opposing subscapularis inserts on lesser tuberosity and internally rotates the humeral head;
- Below the Deltoid:
- deltoid & coracobrachialis draw upper fragment outward & forward while lower fragment is drawn upward;
- it is common for frx ends to displace & override;
- these frx may be amenable to hanging cast