He is doing special exercises to strengthen his intercostal muscles.

He is doing special exercises to strengthen his mentalis muscle.

He is doing special exercises to strengthen his caninus muscle.

His long talk is just like 'a hundred days of sermonizing without a fart.'

He explained in detail about the structure of the sphenoid bone.

He slipped and hit his coccyx.

He fractured his intermediate cuneiform bone in his foot.

He fractured his medial cuneiform bone.

He stepped wrong and fractured his lateral cuneiform bone.

She slipped and hit her coccyx.