The Spine is part of the NHS Care Records Service and the central database where electronic patient records known as summary care records are stored.
Find out more about the 10 key NHS IT projects
♦  NHS Care Records Service
♦  Choose and Book
♦  The Electronic Prescription Service
♦  N3 national broadband network
♦  Picture Archiving and Communications System (Pacs)
♦  The Spine
♦  The Quality Management and Analysis System
♦  GP2GP record transfer
♦  NHSmail- a central email and directory service for the NHS
♦  Secondary Uses Service
Only NHS staff, equipped with smart cards and pin numbers, will be able to access information on the Spine.
A messaging system directs requests for patient details to the various parts of the Spine where the information is held, and retrieves the details.
What progress so far?
About 172,000 summary care records have now been uploaded to the Spine, less than 0.5 per cent of all UK medical records.
Earlier this year CfH said it would halt the rollout of summary care records beyond five early adopter trusts until it considered concerns over the way trusts asked for people's permission before uploading their records electronically.
In September this year, CfH changed the way patients could opt out of having their records uploaded to the summary care record system – so every patient now has to give permission before their records are viewed.
There are more than 516,000 smart card holders who are registered and approved for access to the Spine. Access to the data is strictly controlled, based on a member of staff's role and need.