Forces Displacing Humeral Fractures



- 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



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Saturday, June 23, 2012 5:28 pm