Howdy,
Would you be able to attacher the image again in a different format.
I cannot open zip files on my computer unfortunately.
But without seeing the image I c an still make some comments based on your excellent description.
Firstly the elbow:
If there is a haemarthrosis after trauma as you describe, the likelihood of a fracture is very high and must be investigated with plain radiographs. The most common fracture following a fall is a radial head / neck fracture and this must be investigated. If the plain radiographs are normal, cross sectional imaging may be required.
You can indeed tell the RCL from the ECRB sonographically. If you scan the CEO in long axis and line up the radial head with the humeral capitellum you will observe 3 layers of collagen. The most superficial layer looks more linear and this is the Extensor digitorum (compartment 4) fibres. The deepest layer, which is about 2mm thick is the RCL. In between the superficial and deep layers is other collagen of the CEO, but not pure ECRB. If you see fluid between the radial head and capitellum tracking proximally under the CEO it is highly suggestive of a RCL tear. This also works in the short axis with the collagen closest to the radial head belonging to the annular ligament and the collagen closest tot he lateral epicondyle belonging to the RCL
If you scan in the long axis as described and slide the transducer slightly towards the roof you will see the radial head starting to disappear from view. Stop when you have the slightest bit of radial head still in view and you have lined up pure ECRB, In fact you can see the tendon tracking into the muscle belly. This is nice in the short axis also.
You can see this technique in the fundmentals of the elbow presentation.
Now the wrist:
Again if you have a haemarthrosis a fracture needs exclusion first and foremost. Colles and scaphoid fractures are most common after falling.
Once a fracture is excluded, fluid between the radius and lunate is simply radoiocarpal joint fluid and it is non specific. It does NOT indicate there is a TFCC injury as so many things can cause fluid in this location. TFCC injuries in my view are not reliably seen with ultrasound and if it is suggested an MRI should be undertaken.
Flow in the meniscus homologue area is simply radoiocarpal joint synovitis and this can certainly be associated with trauma.
It is interesting that you are seeing haemarthrosis in DRUL and also 1st CMC joint as these are seperate from the radoiocarpal joint. You can see fluid in the DRUJ by looking around extensor compartment 5 (EDM) Passing over the cartilage of the ulna head and looking for fluid deep to the EDM tendon.
The 1st CMC is a classic OA site and fluid here may be from the trauma or just pre existing OA.
As for PRP,
First exclude a fracture.
Give it some time and see if it settles,
If it is recalcitrant then PRP would be a possible option
Send me those images again and I will follow up with more comments.
Steve.