Upper Extremity Orthotics Flashcards

After reduction of a posterior elbow dislocation, an orthosis typically restricts which motion to prevent re-dislocation?

Answer: Terminal extension

Restricting terminal elbow extension prevents the humeral-ulnar joint from re-dislocating posteriorly while allowing functional range of motion.

For a patient with radial nerve palsy, a dynamic wrist orthosis typically supports the wrist in approximately how many degrees of extension?

Answer: 30–45 degrees

Positioning the wrist in 30–45 degrees of extension optimizes tenodesis and power grip function in radial nerve palsy.

A 'lumbrical bar' component added to an orthosis addresses which deformity?

Answer: Intrinsic minus (claw hand) deformity

A lumbrical bar blocks MCP joint hyperextension, counteracting the intrinsic minus claw hand deformity seen in ulnar or combined nerve injuries.

To maximize mechanical efficiency in a dynamic finger extension orthosis, the outrigger should be positioned so the line of pull is at what angle relative to the middle segment of the finger?

Answer: 90 degrees

A 90-degree angle of pull to the proximal segment of the finger being mobilized generates maximum rotational force with minimal translational force.

A static progressive orthosis differs from a dynamic orthosis primarily because it:

Answer: Uses inelastic components that are manually adjusted at treatment intervals

Static progressive orthoses use non-elastic components (screws, straps, hinges) that are incrementally adjusted as tissue lengthens, delivering a sustained low-load stretch.

Which orthosis design is most appropriate for a patient with median nerve injury at the wrist presenting with thenar muscle weakness?

Answer: Opponens orthosis

An opponens orthosis positions the thumb in palmar abduction and opposition to compensate for thenar muscle paralysis from median nerve injury.

Compared to a volar wrist orthosis, a dorsal wrist orthosis design primarily benefits patients by:

Answer: Leaving the palm free for sensory tasks and object manipulation

A dorsal design leaves the volar surface of the hand unobstructed, preserving palmar sensation and the ability to perform tactile discrimination tasks.