typedef struct _CM_KEY_NODE
{
     WORD Signature;
     WORD Flags;
     LARGE_INTEGER LastWriteTime;
     ULONG Spare;
     ULONG Parent;
     ULONG SubKeyCounts[2];
     union
     {
          struct
          {
               ULONG SubKeyLists[2];
               CHILD_LIST ValueList;
          };
          CM_KEY_REFERENCE ChildHiveReference;
     };
     ULONG Security;
     ULONG Class;
     ULONG MaxNameLen: 16;
     ULONG UserFlags: 4;
     ULONG VirtControlFlags: 4;
     ULONG Debug: 8;
     ULONG MaxClassLen;
     ULONG MaxValueNameLen;
     ULONG MaxValueDataLen;
     ULONG WorkVar;
     WORD NameLength;
     WORD ClassLength;
     WCHAR Name[1];
} CM_KEY_NODE, *PCM_KEY_NODE;

Windows Vista Kernel Structures