OTC Orthopaedic Technologist Certified Upper Extremity Casting 4 — Questions and Answers
Question 1: The proper wrist position for a cock-up (wrist extension) splint is approximately:
- 0 degrees (neutral)
- 20–30 degrees of extension (Correct answer)
- 45 degrees of extension
- 10 degrees of flexion
Correct answer: 20–30 degrees of extension
A cock-up splint places the wrist at 20–30 degrees of extension to relieve carpal tunnel pressure and support the wrist functionally.
Question 2: When applying cast padding (Webril), each layer should overlap the previous layer by approximately what percentage?
- 10–15%
- 25–30%
- 50% (Correct answer)
- 75%
Correct answer: 50%
Cast padding is applied with approximately 50% overlap to ensure even, consistent padding thickness without gaps or bunching.
Question 3: A Muenster cast differs from a standard long arm cast primarily because it:
- Includes finger immobilization
- Extends only to just proximal to the elbow restricting pronation/supination less
- Locks the elbow at 90 degrees with full forearm rotation restriction (Correct answer)
- Uses only fiberglass material
Correct answer: Locks the elbow at 90 degrees with full forearm rotation restriction
A Muenster cast extends above the elbow and contours tightly around the medial and lateral epicondyles, restricting forearm rotation while allowing limited elbow flexion.
Question 4: Which nerve is at greatest risk for compression in the region of the ulnar styloid when casting?
- Median nerve
- Radial nerve
- Ulnar nerve (Correct answer)
- Anterior interosseous nerve
Correct answer: Ulnar nerve
The ulnar nerve passes near the ulnar styloid and pisiform and is vulnerable to direct pressure from inadequately padded cast edges.
Question 5: For a pediatric torus (buckle) fracture of the distal radius, the preferred immobilization is typically:
- Long arm cast for 8 weeks
- Short arm cast or removable splint for 3–4 weeks (Correct answer)
- Surgical fixation
- No immobilization needed
Correct answer: Short arm cast or removable splint for 3–4 weeks
Torus fractures are stable impaction injuries that heal well with short arm casting or a removable splint for 3–4 weeks.
Question 6: The '3-point pressure' principle in fracture casting refers to:
- Applying three strips of plaster for reinforcement
- Molding the cast to apply corrective forces at three specific anatomical points (Correct answer)
- Using three layers of fiberglass for strength
- Checking neurovascular status at three time intervals
Correct answer: Molding the cast to apply corrective forces at three specific anatomical points
Three-point pressure molding applies directional force at the fracture site and two counter-pressure points to maintain reduction while the cast sets.
Question 7: A patient reports their arm cast smells foul and has a wet area on the surface. The most likely cause is:
- The cast is drying out and cracking
- Skin breakdown or wound infection beneath the cast (Correct answer)
- Normal perspiration accumulation
- The stockinette is too tight
Correct answer: Skin breakdown or wound infection beneath the cast
A foul odor with moisture on the cast surface strongly suggests underlying skin breakdown, wound drainage, or infection requiring urgent cast removal.
OTC Orthopaedic Technologist Certified Upper Extremity Casting 4
The proper wrist position for a cock-up (wrist extension) splint is approximately: