Convert to ICD-10-CM: 
923.9 converts approximately to:
- 2015/16 ICD-10-CM S40.019A Contusion of unspecified shoulder, initial encounter
 ICD-9-CM Volume 2 Index entries containing back-references to 
923.9:
- Contusion (skin surface intact) 924.9  arm 923.9 arm 923.9
  upper extremity 923.9 upper extremity 923.9