Table 5. Image quality of foreign bodies in various regions observed via ultrasonography.

Ultrasonography	Visibility on bone	Visibility in muscle	Visibility in air∗
Metal	+++	++++	0
Glass	+++	++++	0
Wood	++	+++	0
Stone	+++	+++	0
Acrylic	++	+	0
Graphite	+++	+++	0
Bakelite	+	+++	0

∗It is not possible to evaluate the foreign bodies' visibility in the air with ultrasonography.