 Spocks emotionless Vulcan nature had not yet been established,  therefore this is the only Trek episode where Spock (without any  alien influence) grins. Spock is also seen limping throughout the  film. Spocks limp was due to the battle on Rigel VII mentioned by  Capt. Pike in his conversation with Dr. Boyce in Pikes quarters.  Two other crew members, Lt. Jose Tyler and another unnamed landing  party member, were also wounded from the battle, wearing bandages on  the forearm and neck, respectively.