What is the primary anatomical site where acute hematogenous osteomyelitis typically initiates in growing long bones of children?

Explanation:
Acute hematogenous osteomyelitis typically begins in the metaphysis of growing long bones. This is due to the unique vascular anatomy in children, where sluggish blood flow in the metaphyseal venous sinusoids (where terminal arterial branches make sharp hairpin turns) creates a favorable environment for bacterial seeding and proliferation. Reference: Tachdjian's Pediatric Orthopaedics, 6th Edition.