Ulnar collateral nerve is?

Ans. is 'b' i.e., Branch of radial nerve supplying medial head of bicepsMedial muscular branch of radial nerve supplies medial head of triceps.This branch accopmponies ulnar nerve in lower third of arm and is, therefore, called as ulnar collateral nerve.Branches of radial nerve Radial nerve is the largest branch of brachial plexus and is the continuation of posterior cord (root value C5_8 T1). The various branches of radial nerve are :-Before spiral groove :- Medial muscular branches to the long and medial head of triceps. Here triceps also gives posterior cutaneous nerve of arm.In the spiral groove :- Posterior muscular branch to lateral & medial head of triceps and direct branch to anconeus. Sensory branches in this area are posterior cutaneous nerve of forearm and lateral cutaneous nerve of arm.At lower end of spiral groove (before elbow) : - Muscular branches to Branchioradialis, Extensor carpi radialis longus.After crossing the elbow, before piercing the supinator :- Extensor carpi radialis brevis and the supinator.After piercing the supinator :- Extensor digitorum, extensor digiti minimi, Extensor Carpi ulnaris, Abductor pollicis longus, extensor pollicis brevis, Extensor pollicis longus, extensor indicis.Among these muscles, radial nerve directly supplies triceps, anconeus, brachioradialis, and extensor carpi radialis longus. All the other muscles are supplied by deep branch of radial nerve, Le., posterior interosseous nerve.