clavicle bone primordium

[cmungall]

[Term]
id: EHDAA2:0000254
name: clavicle bone primordium
namespace: human_developmental_anatomy
is_a: AEO:0000085  ! membrane bone  *********
is_a: AEO:0000213  ! bone condensation
relationship: develops_from EHDAA2:0000179 ! body-wall mesenchyme
relationship: ends_at CS20 ! CS20
relationship: part_of EHDAA2:0001420 ! pectoral girdle
relationship: starts_at CS18 ! CS18

This is dubious, as a primordium is not yet a bone. Maybe AEO:0000085 ! membrane bone should be renamed "membrane element" if the goal is to have a class the groups all temporal stages of the bone.

(I know the clavicle is an interesting case with bone membrane and endochondral aspects, but the issue reported here is orthogonal to this)

Spotted by @wdahdul in obophenotype/uberon#401

[cmungall]

Reply from JB:

n membrane bone the developmental process is as follows
1: uncondensed mesenchyme is present
2: “ is seen with a small area of condensations which spreads out
3: osteoid (bone matrix as yet unmineralised forms) where the inital condensation was, and spreads
4: mineralization then follows and eventually catches up to “almost the edge” - proliferation is in the unmineralised area

In the rat, processes 2-4 take 4 days (at most) in the mandible

In humans, CS18 last 5 days so my guess is that some mineralised bone is present by the end of the stage and it would be tricky to capture the full richness of change over CS18-20. I am not sure how to handle a change to the ontology - the question is which solution is least likely to give ambiguity when a bone is in the process of being formed.