Practical topic 21

Question 1

Give the tarsal flexors of the hindlimb

Answer 1

1. M. Tibialis cranialis
2. M. Peroneus longus
3. M. Peroneus brevis

Question 2

M. Tibialis cranialis

Answer 2

Origin:

• Condylus lateralis, cranial margin of tibia
• Crista tibiae

Insertion:

• Os tarsi 1, medial side
• Mt 1-2

Action:

• Flexes tarsus
• Rotate paw laterally (supinates)

Innervation: N. fibularis profundus

Blood supply: A. tibialis cranialis

Question 3

M. Peroneus longus

Answer 3

Origin:

• Condylus lateralis, cranial margin of tibia.
• Lateral collateral ligament: caput fibulae.

Insertion: First attaches to os tarsi 4+5 (on its plantar surface), then extends to all metatarsal bones, plantar base.

Action: Flexes tarsus

Innervation: N. fibularis profundus

Blood supply: A. tibialis cranialis

Question 4

M. Peroneus brevis

Answer 4

Origin:

• Laterally on distal third of fibula (and partly on tibia)
• From fibula below m. Peroneus longus and m. Extensor digitorum lateralis.

Insertion: Base of Mt 5.

Action: Flexes tarsus.

Innervation: N. fibularis profundus

Blood supply: A. tibialis cranialis

Question 5

Give the digital extensors of the hindlimb

Answer 5

1. M. Extensor digitorum longus
2. M. Extensor digitorum lateralis
3. M. Extensor digiti 1 (hallicus) longus
4. M. Extensor digitalis brevis

Question 6

M. Extensor digitorum longus

Answer 6

Origin: Fossa extensoria on condylus lateralis of femur.

Insertion: Extensor processus of distal phalanx of digits 2-5.

Action:

• Extends joint of digits.
• Flexes tarsus.

Innervation: N. fibularis profundus

Blood supply: A. tibialis cranialis

Question 7

M. Extensor digitorum lateralis

Answer 7

Origin: Proximal third of fibula

Insertion: Unites with long digital extensors tendon to reach digiti 5 distal phalanx.

Action: Extension and abduction of digit 5.

Innervation: Nn. fibulares superficialis et profundus

Blood supply: Aa. tibialis cranialis et dorsalis pedis

Question 8

M. Extensor digi 1 (hallicus) longus

Answer 8

Origin:

• Middle cranial border of fibula.
• Crural interosseus membrane.

Insertion:

• Radiates into fascia over metacarpophalangeal joint of digit 2.
• Small slit to dew claw

Action: Extends digit 2 (and digit 1 if present).

Question 9

M. Extensor digitalis brevis

Answer 9

Origin: Connective tissue over hock

Insertion: M. extensor digitorum longus

Action: To act as an auxillary extensor of the digits 2, 3 and 4

Innervation: N. fibularis profundus

Blood supply: Aa. tibialis cranialis et dorsalis pedis