Most of the time, I have heard this differentiation in context of Humerus bone only. In that context, have a look at the wiki pages on the anatomical and the surgical necks.
From this, and what I remember from anatomy class, this distinction is more a _functional; practical_ distinction rather than that based on strictly defined criteria. Surgical neck denotes the **most commonly fractured region** of the bone, and also the region **most likely to damage the axillary nerve** passing nearby, and hence would have the greatest representation in an orthopedic clinic. The anatomical neck, on the other end, is the classical distinction based on the **centers of ossification** and the **insertion of the capsular ligament of the adjacent shoulder joint** , which gives a greater weightage to its origin and to the anatomical relations (insertions, etc).