On the form, Smith's symptoms were described as 'headache, dizziness, feeling slowed down, feeling in a fog, doesn't feel right, drowsiness'.
Smith was not wearing the additional neck guard on his helmet that came into use following the death of Phillip Hughes after his former Australia teammate was hit by a bouncer in a 2014 domestic Sheffield Shield match in Sydney. "I've got to be able to train a couple of days out and then face fast bowling to make sure my reaction time is in place", Smith also said.
And, while the Australians maintain that Smith's injury on Saturday afternoon was handled correctly, Dr Barry O'Driscoll, the former medical adviser to the International Rugby Board, told Sportsmail he was "shocked" Smith had been allowed to resume his innings after having a concussion medical check in the dressing room.
His half-century at Lord's followed the 30-year-old Smith's superb scores of 144 and 142 in Australia's 251-run win in the series opener at Edgbaston last week - his first Test since he completed a 12-month ban for his role in a ball-tampering scandal in South Africa that cost him the Australia captaincy.
"One of the biggest disappointments for me was the crowd", said Johnson.
The build-up to this match had seen Australia coach Justin Langer question whether Archer had the stamina required for Test cricket, as opposed to one-dayers where bowlers are restricted to a maximum of 10 overs per match.
"I asked him over and over, privately two or three times and in front of the group, the medical team cleared him and he said he was ready to go". "Steve's fitness will be assessed on an ongoing basis".
'Steve will undergo a precautionary scan on his neck on Sunday.
"Despite the unfortunate nature of what has happened, the positive is that the concussion protocol, including the availability of the concussion substitute, which has been recently brought in has served its goal".
During his innings of 92 but before he was felled by the ball to the neck, Smith copped a nasty blow to his left forearm that stopped play for a lengthy amount of time as he was assessed by team medicos. However, in an intense passage of play, Jofra Archer found some great rhythm and managed to hit Smith twice with sharp bounders.
"He won't have any fear because it's just what you do every day".