Sentence:  For example , arrow 17 in Figure 3 portrays the proximal radial epiphysis for boy 34 , whereas the same <WSD>epiphysis</WSD> for girl 2 is portrayed by arrow 18 in Figure 4 . 
Meaning of the word marked with <WSD> tags:  the end of a long bone; initially separated from the main bone by a layer of cartilage that eventually ossifies so the parts become fused