spiral ligament - nonskeletal?

[cmungall]

[Term] id: MA:0001192 name: spiral ligament is_a: MA:0003004 ! nonskeletal ligament relationship: part_of MA:0000243 ! cochlear duct

the FMA def of nonskeletal ligament is:

"Ligament organ that primarily consists of dense connective tissue aggregated into fasciculi which may be admixed with smooth muscle. Examples: ligament of liver, ovarian ligament."

does the spiral ligament satisfy this?

http://en.wikipedia.org/wiki/Spiral\_ligament says it's periosteum (but this is a stub article lifted from an ancient gray's)

snomed classifies it as bony:

...is_a SCTID:314778000 ! Bony cochlea structure ....is_a SCTID:279770008 ! Cochlear canal structure .....is_a SCTID:14596009 ! Spiral cochlear ligament structure ......is_a SCTID:279840005 ! Entire spiral cochlear ligament ***

Original comment by: cmungall

Original Ticket: obo/mouse-anatomy-requests/57

[cmungall]

• assigned_to: nobody --> hayamizu

Original comment by: tfhayamizu

[cmungall]

Actually, SNOMED classifies it as a "Bony cochlea structure" -- that is, it is a structure that is part of the Bony cochlea; i.e. not all parts of a "bone" are themselves "bony".

note: According to BioPortal, SNOMED "Spiral cochlear ligament structure" is also a "Non-skeletal ligament structure"

From the various sources I have been looking at, it appears that the spiral ligament is derived from or is a thickening of the periosteum (which, according to the FMA, is a "membranous layer of organ wall") of the bony cochlea

So then, is it a "ligament"? The FMA definition says that it should (1) be an organ, (2) primarily consist of dense connective tissue and (3) be sggregated into fasciculi.

It appears that the spiral ligament does consist of dense connective tissue, but it is unclear whether there is a fascicular organization. (Most likely not.) Furthermore, as always, I am not sure precisely what it takes to be an "organ".

Consequently, by these criteria, I would have to say that the spiral ligament is NOT a ligament. I will have to consider further about how it should best be re-classified.

Original comment by: tfhayamizu

[cmungall]

• status: open --> open-accepted

Original comment by: tfhayamizu

[cmungall]

I agree.

This paper was used by CL to classify the 5 different fibrocytes of the spiral ligament: http://www.ncbi.nlm.nih.gov/pubmed/18353863

nothing to suggest it's a ligament in the FMA sense...

Original comment by: cmungall

[cmungall]

• status: open-accepted --> closed-accepted

Original comment by: tfhayamizu