The morphology of this fracture is an incomplete basicervical fracture that does not break the contralateral cortex. Due to the very strong cortex, the typical torus and buckle fractures seen in other metaphyseal areas are very rare in this region.
This fracture usually occurs on the superior aspect of the base of the neck and is typically a low-energy injury. In children, this zone has a very thick periosteum (1-2 mm), and this injury rarely results in avascular necrosis (AVN).
Depending on the fracture level, this fracture can either be directly at the attachment of the capsule, or immediately outside the capsule. This determines the presence, or absence, of an intracapsular hemarthrosis.