diff --git a/man4/sd.4 b/man4/sd.4
index e4ba4850a..fcc8e47fa 100644
--- a/man4/sd.4
+++ b/man4/sd.4
@@ -71,7 +71,7 @@ The following
 .IR ioctl s
 are provided:
 .TP
-HDIO_GETGEO
+.B HDIO_GETGEO
 .RS
 Returns the BIOS disk parameters in the following structure:
 .RS
@@ -106,14 +106,14 @@ If the geometry information is not available, zero will be returned for all
 of the parameters.
 .RE
 .TP
-BLKGETSIZE
+.B BLKGETSIZE
 Returns the device size in sectors.
 The
 .BR ioctl (2)
 parameter should be a pointer to a
 .IR long .
 .TP
-BLKRRPART
+.B BLKRRPART
 Forces a re-read of the SCSI disk partition tables.
 No parameter is needed.
 
diff --git a/man4/st.4 b/man4/st.4
index 45e3cfe0a..2409d1025 100644
--- a/man4/st.4
+++ b/man4/st.4
@@ -307,7 +307,9 @@ A special case is available for some HP
 autoloaders.
 If
 .I mt_count
-is the constant MT_ST_HPLOADER_OFFSET plus a number, the number is
+is the constant
+.B MT_ST_HPLOADER_OFFSET
+plus a number, the number is
 sent to the drive to control the autoloader.
 .IP MTLOCK
 Lock the tape drive door.