Due to the anatomic relationship of the radial nerve with the humeral shaft at the lateral supracondylar ridge
, the radial nerve palsy is the most common nerve injury following humeral shaft fractures .
The upper head originated from the lateral supracondylar ridge and oblique popliteal ligament, a little above the origin of lateral head of gastrocnemius (Type 1 origin).
In the third case, the upper belly originated from the lateral supracondylar ridge alone (Not corresponding to any of the above type) and the lower one corresponding to type 5.
(3) Extensor carpi radialis longus attaches to the lateral supracondylar ridge
of the humerus, not the lateral epicondyle, and thus is not involved in LE.
It arose from the lower end of lateral lip of linea aspera above the origin of lateral head of gastrocnemius muscle (from lateral supracondylar ridge
The lateral approach involves elevating the extensor carpi radialis longus and brachioradialis from the lateral supracondylar ridge
. Distally, the interval between the extensor carpi radialis longus and extensor carpi radialis brevis or the interval between the extensor carpi radialis brevis and extensor digitorum communis is developed.
Brachioradialis muscle (Supinator longus) is also a flexor of forearm and arises from upper two-third of lateral supracondylar ridge
of humerus and lateral intermuscular septum normally.