Zara Tindall was "left distressed" over Princess Anne's injuries, according to sources, which saw the royal in hospital for five nights.
The Princess Royal's accident is said to have left her "worried" daughter "shaken to the core" following many years of worrying about her mother.
The 73-year-old was taken to hospital after being struck by a horse at her Gloucestershire estate last week.
The Princess Royal's husband, Vice Admiral Sir Timothy Laurence, has since praised the medical staff who looked after her at Southmead Hospital.
Zara Tindall 'shaken to the core' over Princess Anne's horse incident
PA
Sir Timothy confirmed that Anne is "recovering slowly" following the accident.
However, this has not stopped Zara, 43, from worrying about her mother, a source has claimed.
A source claimed: "This is exactly what Zara's been worried about happening for years now, but her mum hasn't had a chance to slow down with everyone else falling apart.
"It's really shaken Zara to the core and she's desperately hoping this memory is temporary."
Zara Tindall visited Princess Anne during her five-night stay in hospital
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The source continued to tell Woman's Day Magazine: "This has been a huge wake-up call for everyone in the family and they're rightfully distressed."
Zara was seen visiting her mother in hospital shortly after the incident became public news.
The sister of King Charles will now rest at home and follow standard concussion protocols, according to reports.
She is expected to return to public duties when doctors advise that it's safe to do so.
Princess Anne suffered minor head injuries after a horse-related accidentGettyLATEST ROYAL NEWS:
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GWRPrincess Anne's incident happened before King Charles hosted the Emperor and Empress of Japan at Buckingham Palace as part of a three-day State Visit.
It is not the first time the late Queen Elizabeth II's daughter has suffered from a horse-related incident.
In 1976, during the Olympics in Montreal, her horse Goodwill failed to make one of the jumps on the course which caused her to fall.
In 2008, Princess Anne was spotted using a walking stick after being kicked by a horse at her home.