This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
Which muscle causes adduction of wrist joint? 
Select and explain. 
A. Flexor carpi radialis, B. Flexor carpi ulnaris, C. Flexor pollicis longus, D. Flexor digitorum profundus
B: Flexor carpi ulnaris
Answer: B: Flexor carpi ulnaris 
Explanation: Flexor carpi ulnaris Humeral head Ulnar head origin Medial epicondyle of humerus Medial aspect of olecranon process and posterior border of ulna inseion Pisiform bone , inseion prolonged to hook of hamate and base of fifth metacarpal bone nerve supply Ulnar nerve Actions Flexes and adducts the hand at the wrist. Reference page no 107,108- BD chauriasia- upper limb & thorax