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Orthopedic Nurse Certification (ONC®) Exam
| 2025/2026 Edition Complete Study Guide
with 100% Verified Questions & Answers |
Covers Anatomy, Fractures, Joint
Replacement, Postoperative Care, Pain
Management, Pharmacology, Rehab & More |
Graded A+ | La
1. A patient sustains a fracture that disrupts the blood supply to
the femoral head. Which artery is most likely injured?
A. Lateral circumflex femoral artery
B. Medial circumflex femoral artery
C. Superior gluteal artery
D. Obturator artery
,Page 2 of 138
Answer: B. Medial circumflex femoral artery
Rationale: The medial circumflex femoral artery supplies the
femoral head and neck. Disruption (e.g., femoral neck fracture) can
lead to avascular necrosis.
2. Which structure in the knee is most commonly injured in a non-
contact pivoting injury?
A. Posterior cruciate ligament (PCL)
B. Medial collateral ligament (MCL)
C. Anterior cruciate ligament (ACL)
D. Lateral collateral ligament (LCL)
Answer: C. Anterior cruciate ligament (ACL)
Rationale: The ACL is commonly torn during sudden deceleration,
pivoting, or hyperextension. It prevents anterior translation of the
tibia on the femur.
3. A patient with a rotator cuff tear would most likely have
weakness in which motion?
,Page 3 of 138
A. Shoulder adduction
B. Shoulder external rotation
C. Shoulder internal rotation
D. Elbow flexion
Answer: B. Shoulder external rotation
Rationale: The infraspinatus and teres minor (external rotators) are
part of the rotator cuff. Tears commonly cause weakness in
external rotation and abduction.
4. Which nerve is at greatest risk during a total hip arthroplasty
via a posterior approach?
A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Superior gluteal nerve
, Page 4 of 138
Answer: C. Sciatic nerve
Rationale: The posterior approach places the sciatic nerve at risk
due to retraction. Damage can cause foot drop and sensory loss.
5. The primary blood supply to the scaphoid bone enters distally.
A fracture through the proximal pole is at high risk for:
A. Nonunion and avascular necrosis
B. Rapid healing
C. Compartment syndrome
D. Infection
Answer: A. Nonunion and avascular necrosis
Rationale: The scaphoid has a retrograde blood supply from distal
to proximal. A proximal pole fracture disrupts blood flow, leading
to high rates of AVN and nonunion.
6. Which ligament of the knee prevents posterior translation of
the tibia relative to the femur?
A. Anterior cruciate ligament (ACL)
Orthopedic Nurse Certification (ONC®) Exam
| 2025/2026 Edition Complete Study Guide
with 100% Verified Questions & Answers |
Covers Anatomy, Fractures, Joint
Replacement, Postoperative Care, Pain
Management, Pharmacology, Rehab & More |
Graded A+ | La
1. A patient sustains a fracture that disrupts the blood supply to
the femoral head. Which artery is most likely injured?
A. Lateral circumflex femoral artery
B. Medial circumflex femoral artery
C. Superior gluteal artery
D. Obturator artery
,Page 2 of 138
Answer: B. Medial circumflex femoral artery
Rationale: The medial circumflex femoral artery supplies the
femoral head and neck. Disruption (e.g., femoral neck fracture) can
lead to avascular necrosis.
2. Which structure in the knee is most commonly injured in a non-
contact pivoting injury?
A. Posterior cruciate ligament (PCL)
B. Medial collateral ligament (MCL)
C. Anterior cruciate ligament (ACL)
D. Lateral collateral ligament (LCL)
Answer: C. Anterior cruciate ligament (ACL)
Rationale: The ACL is commonly torn during sudden deceleration,
pivoting, or hyperextension. It prevents anterior translation of the
tibia on the femur.
3. A patient with a rotator cuff tear would most likely have
weakness in which motion?
,Page 3 of 138
A. Shoulder adduction
B. Shoulder external rotation
C. Shoulder internal rotation
D. Elbow flexion
Answer: B. Shoulder external rotation
Rationale: The infraspinatus and teres minor (external rotators) are
part of the rotator cuff. Tears commonly cause weakness in
external rotation and abduction.
4. Which nerve is at greatest risk during a total hip arthroplasty
via a posterior approach?
A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Superior gluteal nerve
, Page 4 of 138
Answer: C. Sciatic nerve
Rationale: The posterior approach places the sciatic nerve at risk
due to retraction. Damage can cause foot drop and sensory loss.
5. The primary blood supply to the scaphoid bone enters distally.
A fracture through the proximal pole is at high risk for:
A. Nonunion and avascular necrosis
B. Rapid healing
C. Compartment syndrome
D. Infection
Answer: A. Nonunion and avascular necrosis
Rationale: The scaphoid has a retrograde blood supply from distal
to proximal. A proximal pole fracture disrupts blood flow, leading
to high rates of AVN and nonunion.
6. Which ligament of the knee prevents posterior translation of
the tibia relative to the femur?
A. Anterior cruciate ligament (ACL)
