- 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;
