Prince Philip pulled out of his royal engagements Friday because he is suffering stiffness from a trapped nerve in his neck, Buckingham Palace said.
The husband of Queen Elizabeth II, who turns 85 next month, had a busy day of visits scheduled. The queen would carry out the visits on her own, the palace said.
"He has a trapped nerve and is unable to move his neck," said a palace spokeswoman, speaking on condition of anonymity in keeping with palace policy.
"He's receiving treatment at Buckingham Palace ."
Philip had been due to visit the site where Heathrow Airport 's Terminal 5 is being built and tour nearby Brunel University and the center of Hayes, west London .
The last time he canceled an engagement was eight weeks ago when he was suffering from flu.
The palace said Philip has no engagements over the weekend and is expected to be fit by next week.
With age, the cartilage disks between one spinal bone and the next get narrower. Bony scarring can also develop in the area. Nerves from the spinal cord can easily get trapped, causing pain and limiting movement. The ailment is usually treated with physiotherapy, reports the AP.
The troops of the Southern and Western military districts will begin to return from Russia's southern borders to the points of their permanent deployment starting April 23