Palmar Musculature | The Thenar Muscles

The video tutorial discusses the muscles controlling the wrist and hand, focusing on extrinsic muscles located in the forearm and intrinsic muscles within the hand. It highlights the role of intrinsic muscles in fine motor control and introduces the thenar muscles, which are responsible for thumb movements. The tutorial provides detailed explanations of the abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis muscles, including their origins, insertions, actions, and innervation by the median nerve's recurrent branch.

What is the primary function of extrinsic muscles of the hand?

• To flex the elbow

• To stabilize the shoulder

• To produce movements of the hand and fingers via the wrist joint

• To control fine motor skills

Which muscles are primarily responsible for fine grip and finger manipulations?

• Intrinsic muscles

• Extrinsic muscles

• Triceps brachii

• Biceps brachii

What is the main action of the abductor pollicis brevis muscle?

• Opposition of the thumb

• Abduction of the thumb

• Extension of the thumb

• Flexion of the thumb

Where does the abductor pollicis brevis muscle originate?

• On the scaphoid and trapezium bones

• On the ulna

• On the humerus

• On the radius

What is the primary function of the flexor pollicis brevis muscle?

• To abduct the thumb

• To extend the thumb

• To flex the thumb

• To oppose the thumb

Which nerve innervates the thenar muscles?

• Axillary nerve

• Median nerve

• Radial nerve

• Ulnar nerve

What is the action of the opponens pollicis muscle?

• To oppose the thumb

• To extend the thumb

• To abduct the thumb

• To flex the thumb