Equine Ortho: Carpus, Elbow, Shoulder Flashcards
Median and ulnar nerve block.
Occasionally performed in practice/hospital.
Ulnar nerve:
- approached from caudal aspect of the limb, proximal to accessory carpal bone.
Median nerve:
- on medial antebrachium just ventral to pectorals, caudal to radius.
- will desensitise tissues distal to distal radius.
Carpal joint blocks.
2 effective spaces:
- ABC (antebrachiocarpal).
- MC and CMC (metacarpal and carpometacarpal).
- but diffusion between these when blocking.
- need 5mins prompt assessment.
- dorsal and palmar approaches available.
How are dorsal carpi wounds often sustained by horses?
Trip and fall on roads.
Elbow joint blocks.
Finger on olecranon, other finger on back of olecranon, thumb triangulates with fingers to locate injection site just behind the lateral collateral ligament.
Lateral and caudal approaches.
Infrequent block.
Shoulder and bicipital bursa block.
Injection into bicipital bursa, proximal to biceps, at biceps origin, at proximal humerus.
Bicipital bursa is between biceps muscle and sheath that surrounds it.
Imaging of the carpus.
Radiographs:
- 5 standard views:
– lateromedial.
– dorsopalmar.
– dorsolatero-palmaromedial oblique.
– dorsomediopalmarolateral oblique.
– flexed lateral.
- Additional views:
– dorsoproximal dorsodistal flexed views (skylines).
–> angle depends on region of interest.
–> H&S as limb held with cassette under cannon bone.
Elbow radiographs.
2 views:
- Mediolateral.
– extended leg (?painful).
- craniocaudal.
– WB.
Should radiographs.
2 views.
- Mediolateral.
- Craniomedial caudolateral oblique.
Extend limb cranially.
What anatomical feature allows us to see the shoulder joint more clearly when superimposed with it?
Trachea.
- gas in trachea behind shoulder joint gives a good contrast to view shoulder joint.
- allows reduction of exposure and therefore less scatter and therefore a better quality radiograph.
Carpal osteoporosis.
Common - some cross over in aetiology between osteochondral and chip fractures.
2 populations:
- young racehorses.
– rest and intra-articular hyaluronic acid and steroids or arthroscopy.
- mature pleasure horses.
– rest, intra-articular hyaluronic acid and steroids or arthroscopy or NSAIDs.
Population of Arabs that get intercarpal ligament desmopathy.
- desmitis – distended and painful arthritic carpi.
Enostosis like lesions - radius (also cannon).
Can be incidental finding.
Increased intra-osseous pressure?
Show on nuclear scintigraphy.
Unsure if red herring or actually painful.
May block to median and ulnar nerve when in distal radius or high 4 point when in cannon.
Dx by exclusion.
Shoulder OCD…
1. presentation.
2. radiographic changes.
3. Tx options.
Shoulder osteochondral dissecans.
1. <1yr old w/ prominent lameness.
Muscle atrophy over shoulder, poss. club foot.
Pain on palpation and manipulation.
2. Loss of congruity of articular surfaces.
Flattening of humeral head/glenoid.
Irregular lucencies in subchondral bone with surrounding sclerosis.
Cystic lesions in glenoid.
3. Conservative (poor outcome).
Sx debridement - arthroscopy difficult.
OA a likely consequence.
- Carpal fracture types.
- Aetiology of carpal fractures?
- At which part of the carpus do most fractures occur?
- Chip fractures.
Slab fractures.
Accessory carpal bone fractures.
Comminuted fractures. - Chronic repetitive trauma.
Single episode overload. - Mid carpal joint (more than radiocarpal joint).
Medial aspect - radial carpal bone or 3rd carpal bone.
Presentation of carpal fractures.
Effusion.
Pain on flexion.
Crepitus/instability in severe/multiple fractures only.
Chips moderately lame at onset but ma improve rapidly.
Slabs severe and persistent.
If severe lameness, may do survey radiographs.
If clear, may need scintigraphy.
Carpal chip fractures.
Single articular surface involved.
Can get multiples/joint.
Usually dorsally.
Particularly from radial and 3rd carpal bones in midcarpal joint.
