Exhibit 4.1SUPPLEMENTAL INDENTURE          This Supplemental Indenture, dated as of May 17, 2006 (this “Supplemental Indenture”or “Guarantee”), among the subsidiary guarantors named in Annex A hereto (the“Guarantors”), Manor Care, Inc. (together with its successors and assigns, the“Company”), each other then existing Subsidiary Guarantor under the Indenture referred tobelow, and U.S. Bank National Association (as successor to Wachovia Bank, National Association), asTrustee under the Indenture referred to below.W I T N E S S E T H:          WHEREAS, the Company, the Subsidiary Guarantors and the Trustee have heretofore executed anddelivered an Indenture, dated as of August 1, 2005 (as amended, supplemented, waived or otherwisemodified, the “Indenture”), providing for the issuance of an aggregate principal amount of$400.0 million of 2.125% Convertible Senior Notes due 2035 of the Company (the“Securities”);          WHEREAS, Section 3.3 of the Indenture provides that the Company is required to causeeach Subsidiary (other than a Subsidiary that does not Guarantee obligations under the SeniorCredit Obligations, the 2006 Notes, the 2008 Notes, the 2013 Notes or the 2023 Notes) created oracquired by the Company or one or more of its Subsidiaries or any Subsidiary that Guarantees thepayment of Debt of the Company to execute and deliver to the Trustee a supplemental indenturepursuant to which such Subsidiary will unconditionally Guarantee, on a joint and several basis withthe other Subsidiary Guarantors, the full and prompt payment of the principal of and interest andAdditional Interest, if any, on the Securities on a senior basis; and          WHEREAS, pursuant to Section 9.1 of the Indenture, the Trustee and the Company areauthorized to execute and deliver this Supplemental Indenture to amend the Indenture, without theconsent of any Securityholder, to add to the covenants of the Company for the benefit of theHolders and to add Guarantees with respect to the Securities;          NOW, THEREFORE, in consideration of the foregoing and for other good and valuableconsideration, the receipt of which is hereby acknowledged, the Guarantor, the Company, the otherSubsidiary Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefitof the Holders of the Securities as follows:ARTICLE IDefinitions               SECTION1.1. Defined Terms. As used in this Supplemental Indenture, terms defined in the Indentureor in the preamble or recital hereto are used herein as therein defined, except that the term“Holders” in this Guarantee shall refer to the term “Holders” as defined in the Indenture and theTrustee acting on behalf or for the benefit of such Holders. The words “herein,” “hereof” and“hereby” and other words of similar import used in this Supplemental Indenture refer to this SupplementalIndenture as a whole and not to any particular section hereof.
 

 
ARTICLE IIAmendments to Indenture               SECTION2.1. Agreement to be Bound. The Guarantor hereby becomes a party to the Indenture as aSubsidiary Guarantor and as such will have all of the rights and be subject to all of theobligations and agreements of a Subsidiary Guarantor under the Indenture. The Guarantor agrees tobe bound by all of the provisions of the Indenture applicable to a Subsidiary Guarantor and toperform all of the obligations and agreements of a Subsidiary Guarantor under the Indenture.               SECTION2.2. Guarantee. The Guarantor fully, unconditionally and irrevocably Guarantees to eachHolder of the Securities and the Trustee the Obligations pursuant to Article X of theIndenture on a senior basis.               SECTION 2.3. Amendment. Section 12.2(f) of the Indenture is hereby amended byinserting the phrase “(but without giving effect to the Fundamental Change 105% Exception)”immediately following the word “Change” in the third line thereof.ARTICLE IIIMiscellaneous               SECTION3.1. Notices. All notices and other communications to the Guarantor shall be given asprovided in the Indenture to the Guarantor, at its address set forth below, with a copy to theCompany as provided in the Indenture for notices to the Company.               SECTION3.2. Parties. Nothing expressed or mentioned herein is intended or shall be construed togive any Person, firm or corporation, other than the Holders and the Trustee, any legal orequitable right, remedy or claim under or in respect of this Supplemental Indenture or theIndenture or any provision herein or therein contained.               SECTION3.3. Governing Law. This Supplemental Indenture shall be governed by, and construed inaccordance with, the laws of the State of New York.               SECTION3.4. Severability Clause In case any provision in this Supplemental Indenture shall be invalid, illegal orunenforceable, the validity, legality and enforceability of the remaining provisions shall not inany way be affected or impaired thereby and such provision shall be ineffective only to the extentof such invalidity, illegality or unenforceability.               SECTION3.5. Ratification of Indenture; Supplemental Indentures Part of Indenture. Except asexpressly amended hereby, the Indenture is in all respects ratified and confirmed and all theterms, conditions and provisions thereof shall remain in full force and effect. This SupplementalIndenture shall form a part of the Indenture for all purposes, and every Holder of Securitiesheretofore or hereafter authenticated and delivered shall be bound hereby. The Trustee makes norepresentation or warranty as to the validity or sufficiency of this Supplemental Indenture.
 

 
               SECTION3.6. Counterparts. The parties hereto may sign one or more copies of this SupplementalIndenture in counterparts, all of which together shall constitute one and the same agreement.               SECTION3.7. Headings. The headings of the Articles and the sections in this Guarantee are forconvenience of reference only and shall not be deemed to alter or affect the meaning orinterpretation of any provisions hereof.               IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be dulyexecuted as of the date first above written.         AMERICAN REHABILITATION GROUP, INC.  COMMONWEALTH PHYSICAL THERAPY AND     REHABILITATION, INC.  MANOR CARE OF FLORIDA, INC.,