As well as old leases, you should keep anything that documents the landlord-tenant relationship or supports the items you report on your tax return. If the IRS audits your tax return and you cannot produce the correct verification documents, you may be liable for additional tax and penalties.
The facet joints link the vertebrae together and give them the flexibility to move against each other. The facets are the bony knobs that meet between each vertebra. There are two facet joints between each pair of vertebrae, one on each side.
The thoracic vertebrae are the rib bearing vertebrae. In order to simplify the mechanics of expanding the chest to breath, the thoracic spine is designed to remain stiff and straight no matter what the body is doing. Spinal nerve emerges above the seventh cervical vertebra; spinal nerve emerges below it.