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
Which of the following structure passes through the triangular interval of the arm? 
Select and explain. 
A. Radial nerve, B. Axillary nerve, C. Median nerve, D. Ulnar Nerve
A: Radial nerve
Answer: A: Radial nerve 
Explanation: Ans. is 'a' i.e., Radial nerve RegionBoundariesContentsUpper triangular space of armSuperior: Teres minorInferior : Teres majorLateral: Long head of tricepsCircumflex scapular arteryLower triangular space of armSuperior: Teres majorMedial: Long head of tricepsLateral; Shaft of humerusRadial nerveProfunda brachii vesselsQuadrangular space of armSuperior: Teres minor, subscapularis, joint capsuleInferior :Teres majorMedial: Long head of tricepsLateral: Surgical neck of humerusAxillary nervePosterior circumflex humeral vessels