CEA Human Anatomy & Biomechanics 3 — Questions and Answers
Question 1: Which carpal bones are most commonly involved in carpal tunnel syndrome?
- The tunnel is formed by carpal bones and the flexor retinaculum, not specific carpal bones alone (Correct answer)
- Only the scaphoid and lunate
- Only the hamate and pisiform
- The trapezoid and capitate exclusively
Correct answer: The tunnel is formed by carpal bones and the flexor retinaculum, not specific carpal bones alone
The carpal tunnel is an anatomical passageway bounded by eight carpal bones on three sides and the transverse carpal ligament (flexor retinaculum) on the palmar surface.
Question 2: A task requires a worker to maintain the arm elevated 90° for extended periods. Which structure is MOST at risk for impingement?
- Ulnar nerve at the elbow
- Supraspinatus tendon under the acromion (Correct answer)
- Long head of the biceps at the glenoid
- Infraspinatus muscle at the teres minor
Correct answer: Supraspinatus tendon under the acromion
Sustained shoulder abduction to 90° compresses the supraspinatus tendon in the subacromial space, leading to impingement syndrome.
Question 3: In biomechanics, 'static loading' of muscles differs from 'dynamic loading' because:
- Static loading generates more power output
- Static loading impairs blood flow and accelerates fatigue faster (Correct answer)
- Dynamic loading is always more harmful to tendons
- Static loading increases joint lubrication
Correct answer: Static loading impairs blood flow and accelerates fatigue faster
Static muscle contractions compress blood vessels, reducing oxygen delivery and metabolite removal, causing faster fatigue than rhythmic dynamic contractions.
Question 4: The lumbar vertebrae differ structurally from cervical vertebrae in that lumbar vertebrae have:
- Transverse foramina for vertebral arteries
- Bifid spinous processes
- Much larger and wider vertebral bodies (Correct answer)
- Smaller intervertebral discs relative to body size
Correct answer: Much larger and wider vertebral bodies
Lumbar vertebrae bear the greatest compressive load and therefore have the largest, widest vertebral bodies in the spinal column.
Question 5: Grip strength is generally reduced when the wrist is held in which position?
- Neutral (0°)
- Slight extension (15-30°)
- Flexion or extreme extension (Correct answer)
- Radial deviation
Correct answer: Flexion or extreme extension
Wrist flexion shortens the finger flexors beyond their optimal length-tension relationship, and extreme extension overstretches them, both reducing grip force.
Question 6: Which anatomical structure transmits force from the Achilles tendon to the foot during standing and walking?
- Tibialis anterior
- Plantar fascia
- Calcaneus (heel bone) (Correct answer)
- Navicular bone
Correct answer: Calcaneus (heel bone)
The Achilles tendon attaches directly to the posterior surface of the calcaneus, which absorbs and transmits ground reaction forces.
Question 7: When analyzing a pushing task, the mechanical advantage of using a long-handled tool instead of a short one is that it:
- Reduces the lever arm and therefore the torque
- Increases the moment arm, reducing the force needed to achieve the same torque (Correct answer)
- Eliminates all shoulder involvement
- Increases the velocity of the load
Correct answer: Increases the moment arm, reducing the force needed to achieve the same torque
A longer handle increases the moment arm from the pivot point, allowing the same torque with less applied force (F = T/d).
CEA Human Anatomy & Biomechanics 3
Which carpal bones are most commonly involved in carpal tunnel syndrome?