Flexors and Extensors of the Antebrachium Flashcards
Extensor carpi radialis m.
O: Lateral supracondylar crest of humerus (2 heads in the cat)
I: Dorsal surface of base of metacarpals II and II (long tendon on MC II and short tendon on MC III in cats)
N: Radial n.
A: Extend carpus
Common digital extensor m.
O: Lateral epicondyle of humerus
I: Extensor process of distal phalanx of digits 2-5
N: Radial n.
A: Extend carpus, extend metacarpophalangeal joints of digits 2-5
Lateral digital extensor m.
O: Dog - lateral epicondyle of humerus; Cat - lateral supracondylar ridge of humerus
I: Extensor process of distal (and middle) phalanx of digits 3-5 in the dog and digits 2-5 in cats
N: Radial n.
A: Extend carpus, extend metacarpophalangeal and interphalangeal joints of digits 3-5 in dog; 2-5 in cat
Extensor carpi ulnaris m. (ulnaris lateralis)
O: Lateral epicondyle of humerus
I: Dog - lateral aspect of proximal end of metacarpal V and accessory carpal bone; Cat - metacarpal V
N: Radial n.
A: Abduct the carpus and support the carpus when extended to support weight
Long abductor of digit 1 (abductor policis longus, extensor carpi obliquus)
O: Lateral border and cranial surface of body of ulna, the interosseous membrane (arises from radius in cats)
I: Proximal end of metacarpal I
N: Radial n.
A: Abduct digit I and extend carpus
Supinator m.
O: Lateral epicondyle of humerus
I: Cranial surface of the proximal fourth of the radius
N: Radial n.
A: Rotate forearm laterally so that palmar side of paw faces medially (supination) and flex elbow
Brachioradialis m.
O: Dog - lateral supracondylar crest of humerus; Cat - middle fifth of humerus
I: Dog - distal fourth of radius; Cat - styloid process of radius
N: Radial n.
A: Rotate radius dorsolaterally (supinate)
Flexor carpi radialis m.
O: Medial epicondyle of humerus and medial border of radius
I: Palmar side of base of metacarpals II and III
N: Median n.
A: Flex carpus
Superficial digital flexor m.
O: Medial epicondyle of humerus
I: Palmar surface of PII of digits 2-5
N: Median n.
A: Flex carpus, flex metacarpophalangeal and proximal interphalangeal joints of digits 2-5
Flexor carpi ulnaris m.
O: Ulnar head - caudal border and medial surface of olecranon; Humeral head - medial epicondyle of humerus
I: Accessory carpal bone
N: Ulnar n.
A: Flex carpus
Deep digital flexor m.
O: Humeral head - medial epicondyle of humerus; Ulnar head - proximal 3/4’s of caudal border of ulna; Radial head - middle third of medial bone of radius
I: Palmar surface of P III of digits 1-5
N: Median and ulnar nn.
A: Flex carpus; flex metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of digits 1-5
Pronator teres m.
O: Medial epicondyle of humerus
I: Medial border of the radius between proximal and middle thirds
N: Median n.
A: Rotate forearm medially so that palmar side of paw faces the ground (pronation) and flex elbow
Pronator quadratus m.
O: Ulnar surface apposed to radius
I: Radial surface apposed to ulna
N: Median n.
A: Pronate forepaw
Interossei m.
O: Proximal metacarpals II-V and joint capsule of carpus
I: Proximal sesamoid bones, base of proximal P I, common digital extensor tendon
N: Ulnar n.
A: Flex metacarpophalangeal joints 2-5
Flexor manica
Sleeve that covers the SDF and the DDF on the palmar aspect of the carpus, prevents displacement of those muscles when stepping with paw
Carpal canal
Located on palmar side of carpus. Formed by:
-Flexor retinaculum
-Accessory carpal bones
-Palmar carpal ligament
Structures that course through it:
-DDF and SDF
-Median a. and v.
-Caudal interosseus
-Palmar brs. of radial a. and v.
-Median, musculocutaneous, ulnar nn.
Palmar annular ligaments
Located at level of metacarpophalangeal joints, superficial to flexor manica
One at each metacarpophalangeal joint
Hold each SDF and DDF tendons in place
Digital annular ligaments - proximal and distal
Located proximal and distal to proximal interphalangeal joints
Hold SDF and DDF tendons in place
