diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 7e6c284423..775e9dee8d 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -431,12 +431,12 @@ type mspan struct {
 	// indicating a free object. freeindex is then adjusted so that subsequent scans begin
 	// just past the newly discovered free object.
 	//
-	// If freeindex == nelem, this span has no free objects.
+	// If freeindex == nelems, this span has no free objects.
 	//
 	// allocBits is a bitmap of objects in this span.
 	// If n >= freeindex and allocBits[n/8] & (1<<(n%8)) is 0
 	// then object n is free;
-	// otherwise, object n is allocated. Bits starting at nelem are
+	// otherwise, object n is allocated. Bits starting at nelems are
 	// undefined and should never be referenced.
 	//
 	// Object n starts at address n*elemsize + (start << pageShift).