Flashcards in Upper Extremity Bones / Joints Deck (14):
Order of carpal bones
Some lovers try positions that they can't handle
Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate
Which is most commonly fractured carpal bone?
Mechanism of scaphoid fracture
•Mechanism – scaphoid is bent across the rim of the radius during a FOOSH.
4 reasons scaphoid fractures don't heal well
•Scaphoid is almost completely intra-articular and covered in cartilage so it doesn’t get nutrients from surrounding muscle.
•Little / no callus formation and no periosteum to contribute to healing cells.
•Only one blood vessel, which flows from distal to proximal, so proximal fractures have highest non-union rate.
•Scaphoid fractures are mechanically unstable due to providing a link b/w proximal and distal rows. Motion at fracture site inhibits direct bone healing.
What is most common fracture in hand / wrist?
How well does it heal?
•Characteristic dinner fork deformity.
•Heals very well due to being extra-articular and covered by lots of muscle.
How well does it heal?
Angulated fractures of 5th metacarpal.
Extra-articular and surrounded by hypothenar muscle so it heal swell.
Does casting work?
•Intra-articular fracture of 1st metacarpal (thumb).
•Caused by an axial force against a flexed metacarpal, usually from punching. Usually displaced and involves the articular surface.
•Usually unstable. Cast does NOT work. Free articular fragment is held in place by ligaments.
•Metacarpal is adducted by the adductor and pulled proximally by Abductor Pollicis Longus (KNOW THIS, TEST QUESTION).
Bony skier's thumb
Ulnar collateral ligament of thumb MCP joint pulls away its distal bony insertion from the rest of the proximal phalanx. Ligament avulsion.
What type of mallet finger is worse?
Dorsal triquetral fracture
Dorsal triquetrum is pinched b/w the ulnar styloid and hamate via FOOSH.
Is scaphoid or radius weaker in young vs old people?
Young: scaphoid is weaker than radius
Old: radius is weaker than scaphoid
Type of injury
Site of pain
Which tendon is involved?
•Enthesopathy (should be called epicondylosis b/c it is degenerative rather than inflammatory)
•Histology shows abnormal collagen and matrix production (neuropeptides, non-inflammatory). Densely cellular regions reveal angiofibroplastic hyperplasia and cells permeating the tendon in linear clefts / clusters.
•Pain at lateral epicondyle of distal humerus.
•Mainly involves the extensor carpi radialis brevis tendon
• Conservative: stretching, counterforce bracing, and night wrist splinting
• Others: pulsed US, acupuncture, steroid injection (may make things worse), platelet rich plasma injections, prolotherapy (dextrose injection, modulates pain).
• Goal is to stimulate growth of new collagen fibers
• Surgery – cut degenerative tendon origin and drill / remove outer cortex of lateral epicondyle.
What do fusiform swelling and boggy motion suggest?