This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Extremity, Subject name: Anatomy
An 11-year-old boy falls down the stairs. A physician examines a radiograph of the boy's shoulder region. If the structure indicated by the letter B is fractured, which of the following structures is most likely injured? 
Select and explain. 
A. Musculocutaneous nerve, B. Radial nerve, C. Deep brachial artery, D. Posterior humeral circumflex artery
D: Posterior humeral circumflex artery
Answer: D: Posterior humeral circumflex artery 
Explanation: (d) Fracture of the surgical neck of the humerus occurs commonly and damages the axillary nerve and the posterior humeral circumflex artery.