Internal Medicine/Family Practice Department

Benjamin Beers, MD
Dr. Beers is board certified in Internal Medicine. He graduated from medical school at the University  of Virginia in 2007 and completed residency in Internal Medicine at the University of Pittsburgh Medical in 2010. 

Jennifer Clem, MD
Dr. Clem is board certified in Family Practice.  She graduated from medical school at the University of Alabama in 2006, and completed her residency in Family Medicine at the University of Michigan in 2009.

Paul Cremer, MD
Dr. Cremer is board certified in Internal Medicine.  He graduated from Harvard Medical School in 2007 and completed residency in Internal Medicine at the Massachusetts General Hospital in 2010.

Mary Evans, MD
Dr. Evans is board certified in Internal Medicine.  She graduated from Uniformed Services University of Health Sciences in 2007 and completed residency in Internal Medicine at Boston University Medical Center in 2010.

Martha Geisheker, APN
Mattie is a nationally Certified Adult and Women’s Health Care Nurse Practitioner. She completed her BSN in 1991 from Oregon Heath Sciences University and completed her training as an APN and MSN from OHSU in 1998.


Aaron Kobernick, MD
Dr. Kobernick is a board certified in Internal Medicine and Pediatrics.  He graduated from medical school at Tulane University in 2006 and completed his residency in Internal Medicine and Pediatrics at Tulane in 2010.

Melissa Lee, MD
Dr. Lee is board certified in Pediatrics and Internal Medicine.  She graduated from Yale Medical School in 2001 and completed residency in Internal Medicine and Pediatrics at the Harvard Medicine and Pediatrics Program in 2005.

David Loft, MD
Dr. Loft is board certified in Internal Medicine. He graduated from medical school at the University of Cincinnati in 1976 and completed his residency in New York City. 

Scott McGarvey, MD
Dr. McGarvey is board certified in Pediatrics and Internal Medicine.  He graduated from University of Chicago Pritzker School of Medicine in 2001 and completed his residency in Internal Medicine and Pediatrics at the Harvard Med-Peds Program in 2005.
John Perchalski, MD
Dr. Perchalski is board certified in Family Medicine.  He graduated from University of Florida College of Medicine and served his residency in Internal Medicine at Baptist Memorial Hospital in Memphis, Tennesee.


Eva Presnall, FNP
Eva is  board certified Family Nurse Practitioner. She received her BSN, MSN-FNP, and MPH degrees from Johns Hopkins University in Baltimore, Maryland. Eva is a medical provider for the Adult and Pediatric Outpatient as well as our satellite Adolescent Health Clinic. 



Catherine Rountree, APN
Cathy is a board certified Family Nurse Practitioner.  She completed her BSN in 1984 from Indiana University and completed her training as a FNP and MSN from University of New Mexico in 1996.  Cathy has worked at the Chinle Service Unit since 1984.

Joseph Salay, MD
Dr. Salay is a board certified Family Physician.  He graduated from medical school in 1985 from Rutgers University and completed his residency in Family Medicine at Brown University in 1988.

Steven Williams, MD
Dr. Williams is board certified in Internal Medicine. He graduated from University of Connecticut School of Medicine in 1979 and completed his residency in Internal Medicine at the Montefiore Hospital University in 1986.


Kristin Yeoman, MD
Dr. Yeoman is board certified in Internal Medicine.  She graduated from the George Washington University School of Medicine in 1999 and completed her residency in Internal Medicine at University of Colorado in 2002.

Ali Zakir, MD
Dr. Zakir is board certified in Pediatrics and Internal Medicine.  He graduated from medical school at University of Texas Galveston in 2003 and completed his residency in Internal Medicine and Pediatrics at UT Galveston in 2007.

Adam Zivony, MD
Dr. Zivony is board certified in Internal Medicine.  He graduated from medical school at Medical College of Georgia in 2006 and completed his residency in Internal Medicine at the University of Virginia Health Science Center in 2010.