NCBTMB Anatomy and Kinesiology 4 — Questions and Answers
Question 1: Which structure forms the floor of the popliteal fossa?
- Semimembranosus and biceps femoris
- Popliteus and posterior capsule of the knee (Correct answer)
- Gastrocnemius and plantaris
- Soleus and posterior tibialis
Correct answer: Popliteus and posterior capsule of the knee
The floor of the popliteal fossa is formed by the popliteal surface of the femur, the posterior knee capsule, and the popliteus muscle.
Question 2: What is the open-pack (resting) position of the glenohumeral joint?
- Full abduction and external rotation
- 55° abduction and 30° horizontal adduction (Correct answer)
- 90° flexion and neutral rotation
- 0° adduction and full internal rotation
Correct answer: 55° abduction and 30° horizontal adduction
The resting (open-pack) position of the glenohumeral joint is approximately 55° of abduction with 30° of horizontal adduction, where the joint capsule is most lax.
Question 3: The sciatic nerve is formed by contributions from which spinal levels?
- L2–L4
- L4–S3 (Correct answer)
- L3–S2
- L5–S3
Correct answer: L4–S3
The sciatic nerve is the largest nerve in the body and is formed from spinal levels L4 through S3 via the sacral plexus.
Question 4: Which anatomical landmark is used to identify the level of the sternal angle (angle of Louis)?
- Rib 1 articulation
- Rib 2 articulation (Correct answer)
- Rib 3 articulation
- Rib 4 articulation
Correct answer: Rib 2 articulation
The sternal angle (angle of Louis) is the junction of the manubrium and body of the sternum and corresponds to the articulation of the second rib.
Question 5: Which muscle performs the action of 'unlocking' the fully extended knee to allow flexion to begin?
- Semimembranosus
- Biceps femoris
- Popliteus (Correct answer)
- Gastrocnemius
Correct answer: Popliteus
The popliteus unlocks the knee from its screwed-home position by internally rotating the tibia on the femur, initiating knee flexion.
Question 6: Which type of synovial joint allows the greatest range of motion in multiple planes?
- Hinge joint
- Condyloid joint
- Ball-and-socket joint (Correct answer)
- Pivot joint
Correct answer: Ball-and-socket joint
Ball-and-socket joints (e.g., hip and shoulder) allow multiaxial movement including flexion, extension, abduction, adduction, rotation, and circumduction.
Question 7: The anatomical snuffbox is bounded anteriorly by which tendon?
- Extensor pollicis longus
- Abductor pollicis longus and extensor pollicis brevis (Correct answer)
- Flexor pollicis longus
- Extensor carpi radialis longus
Correct answer: Abductor pollicis longus and extensor pollicis brevis
The anterior (radial) boundary of the anatomical snuffbox is formed by the tendons of the abductor pollicis longus and extensor pollicis brevis.
NCBTMB Anatomy and Kinesiology 4
Which structure forms the floor of the popliteal fossa?