CCEP Anatomy & Biomechanics of Extremities 5 — Questions and Answers
Question 1: The acromioclavicular joint is reinforced primarily by which ligaments that provide vertical and horizontal stability respectively?
- Coracoacromial and glenohumeral ligaments
- Coracoclavicular and acromioclavicular ligaments (Correct answer)
- Sternoclavicular and costoclavicular ligaments
- Coracoacromial and coracohumeral ligaments
Correct answer: Coracoclavicular and acromioclavicular ligaments
The coracoclavicular ligaments (trapezoid and conoid) provide vertical stability, while the acromioclavicular ligaments provide horizontal (anteroposterior) stability.
Question 2: The Q-angle of the knee is measured between the line of pull of the quadriceps and which other line?
- The long axis of the fibula
- The line from the tibial tubercle through the center of the patella to the ASIS (Correct answer)
- The anatomical axis of the femur
- The line from the patella to the lateral femoral condyle
Correct answer: The line from the tibial tubercle through the center of the patella to the ASIS
The Q-angle is the angle between the quadriceps force vector (ASIS to patellar center) and the patellar tendon line (patellar center to tibial tubercle); normal is approximately 10–18°.
Question 3: The interosseous membrane of the forearm primarily transfers axial loads from which bone to which bone?
- Radius to ulna (proximal to distal) (Correct answer)
- Ulna to radius
- Radius to ulna (distal to proximal)
- Equally between radius and ulna
Correct answer: Radius to ulna (proximal to distal)
The fibers of the interosseous membrane run obliquely, transferring compressive loads from the radius (which receives ~80% of wrist forces) proximally to the ulna.
Question 4: Which extensor tendon compartment of the wrist contains the extensor pollicis longus, and its abrupt change in direction around Lister's tubercle predisposes it to what complication?
- First compartment; de Quervain's tenosynovitis
- Third compartment; spontaneous rupture (Correct answer)
- Second compartment; intersection syndrome
- Fourth compartment; extensor tendinopathy
Correct answer: Third compartment; spontaneous rupture
The EPL occupies the third compartment and wraps around Lister's tubercle, which acts as a pulley; this sharp change in direction can cause attritional or spontaneous rupture.
Question 5: When assessing ankle dorsiflexion range of motion with the knee extended versus knee flexed, a restriction only with knee extended suggests tightness in which structure?
- Anterior joint capsule
- Peroneal tendons
- Gastrocnemius muscle (Correct answer)
- Soleus muscle
Correct answer: Gastrocnemius muscle
Because the gastrocnemius crosses the knee joint, dorsiflexion restriction that improves when the knee is flexed (taking tension off the gastrocnemius) indicates gastrocnemius, not soleus, tightness.
Question 6: The femoral neck angle of inclination (coxa vara vs. coxa valga) directly influences which mechanical parameter at the hip?
- Acetabular version
- Abductor muscle moment arm and joint reaction force (Correct answer)
- Iliofemoral ligament tension
- Femoral anteversion
Correct answer: Abductor muscle moment arm and joint reaction force
The neck-shaft angle determines the moment arm of the abductors; coxa vara shortens the abductor moment arm, requiring greater muscle force and increasing joint reaction force.
Question 7: The 'Boutonnière deformity' of the finger involves which combination of joint positions?
- PIP hyperextension and DIP flexion
- PIP flexion and DIP hyperextension (Correct answer)
- MCP flexion and PIP extension
- MCP hyperextension and DIP flexion
Correct answer: PIP flexion and DIP hyperextension
Boutonnière deformity involves PIP flexion with DIP hyperextension, caused by disruption of the central slip allowing lateral bands to migrate volarly at the PIP.
CCEP Anatomy & Biomechanics of Extremities 5
The acromioclavicular joint is reinforced primarily by which ligaments that provide vertical and horizontal stability respectively?