Exhibit 3.310

CERTIFICATE OF INCORPORATION

OF

NATIONAL HEALTHCARE OF MT. VERNON, INC.

1. The name of the corporation is:

NATIONAL HEALTHCARE OF MT. VERNON, INC.

2. The address of its registered office in the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County of New Castle. The name of its registered agent at such address is The Corporation Trust Company.

3. The nature of the business or purposes to be conducted or promoted is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of Delaware.

4. The total number of shares of stock which the corporation shall have authority to issue is One Thousand (1,000) and the par value of each of such shares is One Dollar ($1.00) amounting in the aggregate to One Thousand Dollars ($1,000.00).

5. The board of directors is authorized to make, alter or repeal the by-laws of the corporation. Election of directors need not be by written ballot.

6. The name and mailing address of the incorporator is:

L. M. Custis

Corporation Trust Center

1209 Orange Street

Wilmington, Delaware 19801

I, THE UNDERSIGNED, being the incorporator hereinbefore named, for the purpose of forming a corporation pursuant to the General Corporation Law of Delaware, do make this certificate, hereby declaring and certifying that this is my act and deed and the facts herein stated are true, and accordingly have hereunto set my hand this 5th day of June, 1985.

/s/ L. M. Custis

L. M. Custis

State of Delaware

Secretary of State

Division of Corporations

ILLEGIBLE

FILED 09:00 AM 11/01/1994

944209846 – 2063507

CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED

OFFICE AND REGISTERED AGENT

OF

NATIONAL HEALTHCARE OF MT. VERNON, INC.

The Board of Directors of:

NATIONAL HEALTHCARE OF MT. VERNON, INC.

a Corporation of the State of Delaware, on this 25^th day of October, A.D. 1994, do hereby resolve and order that the location of the Registered Office of this Corporation within this State be, and the same hereby is:

1013 Centre Road, in the City of Wilmington, in the County of New Castle, Delaware, 19805.

The name of the Registered Agent therein and in charge thereof upon whom process against the Corporation may be served, is:

CORPORATION SERVICE COMPANY.

NATIONAL HEALTHCARE OF MT. VERNON, INC.

a Corporation of the State of Delaware, does hereby certify that the foregoing is a true copy of a resolution adopted by the Board of Directors at a meeting held as herein stated.

IN WITNESS WHEREOF, said corporation has caused this Certificate to be signed by Sara Martin-Michels, Assistant Secretary this 25^th day of October A.D. 1994.

/s/ Sara Martin-Michels

Authorized Officer

State of Delaware

Secretary of State

Division of Corporations

Delivered 11:47 AM 11/12/2003

FILED 10:00 AM 11/12/2003

SRV 030724188 – 2063507 FILE

CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED OFFICE

AND OF REGISTERED AGENT

It is hereby certified that:

1. The name of the corporation (hereinafter called the “Corporation”) is

NATIONAL HEALTHCARE OF MT. VERNON, INC.

2. The registered office of the Corporation within the State of Delaware is hereby changed to 9 East Loockerman Street, Suite 1B, City of Dover 19901, County of Kent.

3. The registered agent of the Corporation within the State of Delaware is hereby changed to National Registered Agents, Inc., the business office of which is identical with the registered office of the corporation as hereby changed.

4. The Corporation has authorized the changes hereinbefore set forth by resolution of its Board of Directors.

Signed on 11-4-03.

/s/ Sherry Connelly

Sherry Connelly

Asst. Secretary

State of Delaware

Secretary of State

Division of Corporations

Delivered 01:45 PM 09/24/2007

FILED 01:16 PM 09/24/2007

SRV 071044462 – 2063507 FILE

CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED OFFICE

AND OF REGISTERED AGENT

OF

NATIONAL HEALTHCARE OF MT. VERNON, INC.

It is hereby certified that:

1. The name of the corporation (hereinafter called the “corporation”) is:

NATIONAL HEALTHCARE OF MT. VERNON, INC.

2. The registered office of the corporation within the State of Delaware is hereby changed to 2711 Centerville Road, Suite 400, City of Wilmington 19808, County of New Castle.

3. The registered agent of the corporation within the State of Delaware is hereby changed to Corporation Service Company, the business office of which is identical with the registered office of the corporation as hereby changed.

4. The corporation has authorized the changes hereinbefore set forth by resolution of its Board of Directors.

Signed on September 11, 2007

/s/ Rachel A. Seifert
Name:	Rachel A. Seifert
Title:	Sr. Vice President & Secretary