Anatomy - flexors and extensors of the antebrachium, carpus, and digits

Question 1

what is the origin, insertion, action, and innervation of the extensor carpi radialis

Answer 1

- origin: the lateral supracondylar crest (distal lateral end of humerus)
- insertion: small tuberosities on the dorsal surface of the base of metacarpals 2 &3
- action: extend the carpal joints
- innervation: radial nerve

Question 2

what is the origin, insertion, action, and innervation of the common digital extensor

Answer 2

- origin: lateral epicondyle of the humerus
- insertion: extensor process of the digital phalanges of digits 2,3,4, and 5
- action: extend the joints of the four principal digits and the carpus
- innervation: radial nerve

Question 3

what is the origin, insertion, action, and innervation of the lateral digital extensor

Answer 3

- origin: lateral epicondyle of the humerus
- insertion: proximal ends of all the phalanges of digits 3, 4, 5
- action: extend the carpal joints of the carpus and digits 3,4, and 5
- innervation: radial nerve

Question 4

what is the origin, insertion, action, and innervation of the ulnaris lateralis

Answer 4

- origin: lateral epicondyle of the humerus
- insertion: lateral aspect of the proximal end of metacarpal 5 and the accessory carpal bone
- action: extend carpus, abduct carpus
- innervation: radial nerve

Question 5

what is the origin, insertion, action, and innervation of the supinator

Answer 5

- origin: lateral epicondyle of the humerus
- insertion: cranial surface of the proximal fourth of the radius
- action: rotate the forearm laterally so that the palmar side of the paw faces medially (supination); to flex elbow joint
- innervation: radial nerve

Question 6

what is the origin, insertion, action, and innervation of the abductor digiti I longus (abductor pollicis longus/ extensor carpi obliquus)

Answer 6

- origin: lateral border and cranial surface of the body of the ulna; the interosseous membrane
- insertion: proximal end of metacarpal 1
- action: abduct the first digit or pollex and extend the carpal joints
- innervation: radial nerve

Question 7

what is the origin, insertion, action, and innervation of the pronator teres

Answer 7

- origin: medial epicondyle of the humerus
- insertion: medial border of the radius
- action: rotate the forearm medially so that the palmar side of the paw faces the ground (pronation); to flex the elbow
- innervation: median nerve

Question 8

what is the origin, insertion, action, and innervation of the flexor carpi radialis

Answer 8

- origin: medial epicondyle of the humerus and the medial border of the radius
- insertion: palmar side of the base of metacarpals 2 and 3
- action: flex the carpal joints
- innervation: median nerve

Question 9

what is the origin, insertion, action, and innervation of the superficial digital flexor

Answer 9

- origin: medial epicondyle of the humerus
- insertion: palmar surface of the base (proximal end) of the middle phalanges of digits 2, 3, 4, and 5
- action: flex the carpal, metacarpophalangeal, and proximal interphalangeal joints of digits 2, 3, 4, 5
- innervation: median nerve

Question 10

what is the origin, insertion, action, and innervation of the flexor carpi ulnaris

Answer 10

- origin: ulnar head - caudal border and medial surface of the olecranon; humeral head - medial epicondyle of the humerus
- insertion: accessory carpal bone
- action: flex carpus
- innervation: ulnar nerve

Question 11

what is the origin, insertion, action, and innervation of the deep digital flexor

Answer 11

- origin: humeral head - medial epicondyle of the humerus; ulnar head - caudal border of the ulna; radial head - medial border of radius
- insertion: flexor tubercle on the palmar surface of the distal phalanx of each digit
- action: flex the carpal and metacarpophalangeal joints of the digits
- innervation: median and ulnar nerves