**Exhibit 21****SUBSIDIARIES OF THE REGISTRANT**               State of       Incorporation or Name Assumed Names  Organization ARC Development Corporation     TennesseeARC Dry Creek, Inc.     TennesseeARC Financial Services Corporation     TennesseeARC of Bellingham, L.P.     TennesseeARC of Georgia, LLC     TennesseeARC Worcester Center, L.P. ARC Worcester Center Limited Partnership (MA) TennesseeASC of Hammond, Inc.     DelawareASC of New Albany, Inc.     IndianaAmbulatory Resource Centres Investment Company, Inc.     WashingtonAmbulatory Resource Centres of Florida, Inc.     FloridaAmbulatory Resource Centres of Massachusetts, Inc.     TennesseeAmbulatory Resource Centres of Texas, Inc.     TennesseeAmbulatory Resource Centres of Washington, Inc.     TennesseeAmbulatory Resource Centres of Wilmington, Inc.     TennesseeAmbulatory Surgery Center of Cool Springs, LLC     TennesseeAmbulatory Surgery Center of Worcester, LLC     DelawareAnimas Surgical Hospital, LLC     DelawareBayside Endoscopy Center, LLC     Rhode IslandBirmingham Surgery Center, LLC     DelawareCape Coral Ambulatory Surgery Center, LLC     FloridaCardinal Sleep Centers of St. Charles, LLC     IllinoisCentral Austin Ambulatory Surgery Center, L.P.     TennesseeChesterfield Spine Center, LLC     DelawareCMMP Surgical Center, L.L.C.     MissouriCSS Services, LLC     South CarolinaCypress Surgery Center, LLC     DelawareDeLand Surgery Center, Ltd. DeLand Surgery Center (FL) FloridaDry Creek Imaging, LLC     DelawareDry Creek Surgery Center, LLC     ColoradoDSC Anesthesia, LLC     FloridaEast Houston Surgery Center, Ltd.     TexasFairview Maple Grove Surgery Center, LLC     DelawareHMFW Surgery Center, L.P.     TexasHouston PSC — I, Inc.     TexasJacksonville Beach Surgery Center, L.P. Jacksonville Beach Surgery Center (FL) TennesseeKent, LLC     Rhode IslandLakeside Women’s Center of Oklahoma City, LLC     OklahomaLargo Endoscopy Center, L.P. Tampa Bay Regional Surgery Center (FL) TennesseeLargo Surgery, LLC West Bay Surgery Center (FL) FloridaLubbock SurgiCenter, Inc.     Texas
 

 
               State of       Incorporation or Name Assumed Names  Organization MediSphere Health Partners Management of Tennessee, Inc.     TennesseeMediSphere Health Partners — Oklahoma City, Inc.     TennesseeNSC Edmond, Inc.     OklahomaNew Albany Outpatient Surgery, L.P.     DelawareNortheast Baptist Surgery Center, LLC     TexasNorth River Surgical Center, LLC     DelawareNorthStar Surgical Center, L.P.     TexasNovi Surgery Center, LLC     DelawareOne Nineteen ASC, LLC     DelawareOrange City Surgical, LLC     DelawareOrlando Surgery Center II, Ltd. Orlando Surgery Center (FL) FloridaOrthopaedic Surgery Center of Asheville, L.P.     TennesseePSC Development Company, LLC     DelawarePSC Operating Company, LLC     DelawarePSC of New York, L.L.C.     DelawarePhysicians of Edmond, LLP     OklahomaPhysicians Surgery Center, LLC Lee Island Coast Surgery Center (FL) DelawarePhysicians Surgical Care, Inc.     DelawarePhysicians Surgical Specialty Hospital, LLC     LouisianaPickaway Surgery Center, Ltd.     OhioPremier Ambulatory Surgery of Duncanville, Inc.     DelawareQuahog Holding Company, LLC     DelawareRecovery Care, L.P.     IllinoisRecovery Care, Inc.     IllinoisSARC/Asheville, Inc.     TennesseeSARC/Circleville, Inc.     TennesseeSARC/Columbia, Inc.     TennesseeSARC/DeLand, Inc.     TennesseeSARC/Ft. Myers, Inc.     TennesseeSARC/FW, Inc.     TennesseeSARC/Georgia, Inc.     TennesseeSARC/Jacksonville, Inc.     TennesseeSARC/Kent, LLC     TennesseeSARC/Knoxville, Inc.     TennesseeSARC/Largo, Inc.     TennesseeSARC/Largo Endoscopy, Inc.     TennesseeSARC/Metairie, Inc.     TennesseeSARC/Providence, Inc.     TennesseeSARC/San Antonio, LLC     TennesseeSARC/Savannah, Inc.     TennesseeSARC/St. Charles, Inc.     TennesseeSARC/Vincennes, Inc.     TennesseeSARC/West Houston, LLC     TennesseeSARC/Worcester, Inc.     TennesseeSavannah Outpatient Anesthesia, LLC     DelawareSavannah Outpatient Foot and Ankle Surgery, LLC     Delaware
 

 
               State of       Incorporation or Name Assumed Names  Organization SI/Dry Creek, Inc     TennesseeSMBIMS 119, LLC     TennesseeSMBIMS Birmingham, Inc.     TennesseeSMBIMS Brooksville, Inc.     TennesseeSMBIMS Durango, LLC     TennesseeSMBIMS Florida I, LLC     TennesseeSMBIMS Greenville, LLC     TennesseeSMBIMS Kirkwood, Inc.     TennesseeSMBIMS Maple Grove, LLC     TennesseeSMBIMS Novi, LLC     TennesseeSMBIMS Orange City, LLC     TennesseeSMBIMS Steubenville, Inc.     TennesseeSMBIMS Tampa, LLC     TennesseeSMBIMS Temple, LLC     TennesseeSMBIMS Tuscaloosa, Inc.     TennesseeSMBIMS Wichita, LLC     TennesseeSMBISS Arcadia, LLC     TennesseeSMBISS Beverly Hills, LLC     TennesseeSMBISS Chesterfield, LLC     TennesseeSMBISS Encino, LLC     TennesseeSMBISS Irvine, LLC     TennesseeSMBISS Roswell, LLC     TennesseeSMBISS Sandy Springs, LLC     TennesseeSMBISS Thousand Oaks, LLC     TennesseeSpecialty Surgical Center, LLC     CaliforniaSpecialty Surgical Center of Arcadia, LLC     CaliforniaSpecialty Surgical Center of Arcadia, L.P.     CaliforniaSpecialty Surgical Center of Beverly Hills, L.P.     CaliforniaSpecialty Surgical Center of Encino, LLC     CaliforniaSpecialty Surgical Center of Encino, L.P.     CaliforniaSpecialty Surgical Center of Irvine, LLC     CaliforniaSpecialty Surgical Center of Irvine, L.P.     CaliforniaSpecialty Surgical Center of Thousand Oaks, LLC     CaliforniaSpecialty Surgical Center of Thousand Oaks, L.P.     CaliforniaSouth Shore Operating Company, L.L.C.     DelawareSurgery Center of Duncanville, L.P.     TexasSurgery Center of Edmond, LLC     OklahomaSurgery Center of Hammond, LLC     DelawareSurgery Center Partners, LLC     DelawareSurgiCare of Deland, Inc.     FloridaSymbion Ambulatory Resource Centres, Inc.     TennesseeSymbionARC Management Services, Inc.     TennesseeSymbionARC Support Services, LLC     TennesseeSymbion Imaging, Inc.     TennesseeThe Center for Special Surgery, LLC     DelawareThe Hand Surgery Center of Louisiana, L.P.     Tennessee
 

 
               State of       Incorporation or Name Assumed Names  Organization The Surgery Center, LLC     GeorgiaThe Surgery Center of Ocala, LLC     TennesseeThe Surgery Center of Temple, LLC     DelawareTexarkana Surgery Center GP, Inc.     TexasTexarkana Surgery Center, L.P.     DelawareTOSF, LLC     DelawareUniPhy Healthcare of Eugene/Springfield I, Inc.     TennesseeUniPhy Healthcare of Johnson City VI, LLC     TennesseeUniPhy Healthcare of Louisville, Inc.     TennesseeUniPhy Healthcare of Maine I, Inc.     TennesseeUniPhy Healthcare of Memphis I, LLC     TennesseeUniPhy Healthcare of Memphis II, Inc.     TennesseeUniPhy Healthcare of Memphis III, Inc.     TennesseeUniPhy Healthcare of Memphis IV, Inc.     TennesseeUniversity Ambulatory Surgical Center     TennesseeVASC, Inc.     IllinoisValley Ambulatory Surgery Center, L.P.     IllinoisValley Medical Inn, L.P.     IllinoisValley Sleep Centers, LLC     IllinoisValley Surgical Center, Ltd.     OhioVillage SurgiCenter, Inc.     DelawareVillage SurgiCenter, Limited Partnership     DelawareVincennes Surgery Center, L.P.     DelawareWilmington Surgery Center, L.P.     Tennessee