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4 Cards in this Set
- Front
- Back
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What muscle is innervated by branches of both the median and ulnar nerves? A. flexor carpi ulnaris B. flexor digitorum profundus C. flexor digitorum superficialis D. flexor pollicis longus E. pronator quadratus |
The median and ulnar nerve both innervate flexor digitorum profundus. Flexor carpi ulnaris is innervated by the ulnar nerve only. Flexor digitorum superficialis and flexor pollicis longus are innervated by the median nerve. Pronator quadratus is innervated by the anterior interosseus nerve, which is a branch of the median nerve. |
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Interruption of the median nerve in the cubital fossa affects what movement(s) of the thumb? a. Flexion b. Opposition c. Both d. Neither |
C. both: The recurrent branch of median n. innervates thenar compartment of hand. This includes: opponens pollicis, which opposes the thumb, and flexor pollicis brevis, which helps to flex the thumb. |
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Compression of the median nerve in the carpal tunnel affects which hand muscle(s)? a. Dorsal interossei b. Flexor pollicis brevis c. Flexor pollicis longus d. Opponens digiti minimi e. Palmar interossei |
B. flexor pollicis brevis. The recurrent branch of the median nerve innervates the thenar compartment of the hand, including flexor pollicis brevis, abductor pollicis brevis, and opponens pollicis. So, if the median nerve was compressed, all of these muscles might be affected. The dorsal interossei, palmar interossei, and opponens digiti minimi are all muscles of the hand which are innervated by the deep branch of the ulnar nerve. Flexor pollicis longus is innervated by the median nerve, but it is a forearm muscle which is proximal to the carpal tunnel. Therefore, it would not be affected by compressing the median nerve in the carpal tunnel. |
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Structures within the carpal tunnel include the: Radial bursa Ulnar bursa Both Neither |
The radial bursa and ulnar bursa are both found in the carpal tunnel. These bursae are complex synovial coverings that protect the flexor tendons. The carpal tunnel is formed where the flexor retinaculum spans from the scaphoid and trapezium to the hamate and pisiform, deep and slightly distal to the palmar carpal ligament. This creates a canal that covers the flexor digitorum superficialis tendons, the flexor digitorum profundus tendons, the tendon of flexor pollicis longus, and the median nerve. These tendons in the carpal tunnel are covered by the ulnar and radial bursae. The flexor digitorum superficialis and flexor digitorum profundus tendons are covered by the ulnar bursa, and the tendon of flexor pollicis longus is covered by the radial bursa. So, both bursae are in the carpal tunnel. |
