Help to get element under one TR

Help to get element under one TR

not sure what is wrong, when I tried to get the below element
 
<tr id='123'>.....<span class='userstatus'....
<tr id='124'>.....<span class='userstatus'....
<tr id='125'>.....<span class='userstatus'....
 
I tried $('#123 .userstatus'), I expect it return one element, but it returns 3, any idea how I get the userstatus span under a special tr?
 
Thanks