Practical topic 15

Question 1

Give the carpal extensors of the forelimb

Answer 1

1. M. Extensor carpi radialis
2. M. Extensor carpi ulnaris (ulnaris lateralis)
3. M. Extensor digitorum communis
4. M. Abductor digiti 1 longus
5. M. Extensor digitorum lateralis

Question 2

Give the digital extensors of the forelimb

Answer 2

1. Extensor digitorum communis
2. Extensor digitorum lateralis
3. Extensor digiti 1 et 2
4. Abductor digiti 1 (policis) longus

Question 3

M. Extensor carpi radialis

Answer 3

Origin: Crista epicondylus lateralis of humerus

Insertion: Tuberositas ossis metacarpalis 2-3 (dorsal surface of metacarpals base)

Action: Strongest extensor of the carpal joint

Innervation:N. radialis

Blood supply:

• A. interossea cranialis
• A. brachialis
• A. medianus

Question 4

M. Extensor digitorum communis

Answer 4

Origin: Epicondylus lateralis of humerus.

Insertion: Processus extensorius of distal phalanx of digits 2-5.

Action: Extends carpus and joints of digits 2-5.

Innervation: N. radialis

Blood supply:

• A. interossea cranialis
• A. medialis
• A. brachialis

Question 5

M. Extensor digitorum lateralis

Answer 5

Origin:

• Epicondylus lateralis of humerus
• Ligamentum collaterale laterale

Insertion:

• Goes to digits 3-5. At the level of the first digit it unites with tendons from m. Extensor digitorum communis and interosseus muscles.
• Inserts on proximal ends of all the distal phalanges of digits 3-5, mainly on processus extensorius of the distal phalanges

Action: Extends the carpal joint and digits 3-5.

Innervation: N. radialis

Blood supply

• A. interossea cranialis
• A. mediana
• A. brachialis

Question 6

M. Abductor digiti 1 (pollicis) longus

Answer 6

Origin: Adjacent lateral surface of radius and ulna, and from the interosseus membrane.

Insertion: Mc 1 base medially

Action:

• Abducts the first digit (pollex)
• Extends the carpal joint.

Innervation: N. Radialis

Blood supply: A. brachialis superficialis

Question 7

M. extensor carpi ulnaris

Answer 7

Origin: Epicondylus lateralis (behind collateral ligament)

Insertion:

• Lateral aspect of mc 5 base.
• Attaches with a short and strong tendon to accessory carpal bone.

Action:

• Supports carpus when extended to bear weight.
• Helps in flexion
• Abducts and lateral rotation of carpal joint since its attachemnt to os carpi accessorium.

Innervation: N. radialis

Blood supply:

• A. interossea cranialis
• A. brachialis
• A. ​medianus

Question 8

M. Extensor digiti 1 et 2 (pollicis et indicis)

Answer 8

Origin:

Middle third of ulna, laterally. (Adjacent to m. Abductor to m. Abductor digiti 1 longus).

Insertion

• Pollicis:
  
  • Head of Mc 1
• Indicis:
  
  • Unites with m. Extensor digitorum communis.

Together inserts on distal phalanx of digit 2.

Action:

• Extends digits 1-2.
• Indicis adducts dew claw (which is not in contact with the ground)

Innervation: N. radialis

Blood supply:

• A. interossea cranialis
• A. medialis
• A. brachialis

Question 9

Give the brances of n. radialis

Answer 9

• N. radialis superficialis
  
  • Runs along with v. cephalica
• N. radialis profundus

Question 10

Where does n. radialis arise from?

Answer 10

C7-T1(2) spinal nerves

Question 11

What type of nerve is n. radialis

Answer 11

Motor nerve

Question 12

Where does the n. radialis run?

Answer 12

Caudally to a. brachialis (along with n. mediana and n. ulnaris)

→ enters space between m. triceps brachii and humerus (distal to m. teres major)

Runs on m. brachialis (follows sulcus brachialis), goes over lateral side

Question 13

Which muscles in innervated by n. radialis?

Answer 13

• All extensors of the elbow (m. triceps brachii)
• Carpal and phalageal extensors (the extensors in the topic)

Question 14

Which vessels belong to the superficial venous system?

Answer 14

• V. cephalica
  
  • V. axillobrachialis
  • V. mediana cubiti
  • V. cephalica accessoria

Question 15

Which vessel anastomoses with v. axillborachialis

Answer 15

V. circumflexa humerale caudale

Question 16

Which vessel anastomoses with v. mediana cubiti

Answer 16

V. brachialis superficialis → v. brachialis

Question 17

V. cephalica accessoria

1. Arise from
2. Becomes

Answer 17

1. V. cephalica
2. V. digitalis dorsalis communis 3

Question 18

Craniolateral

Answer 18

1. M. extensor carpi radialis
2. M. extensor digitorum communis
3. M. extensor digitorum lateralis
4. M. ulnaris lateralis
5. M. brachioradialis
6. M. abductor pollicis longus
7. Extensor retinaculum

Question 19

Answer 19

1. M. extensor digitorum communis
2. M. extensor digitorum lateralis
3. M. extensor carpi radialis
4. M. ulnaris lateralis
5. M. anconeus

• * Lateral epicondyle of humerus

Question 20

Answer 20

1. V. cephalica
2. V. jugularis externa
3. V. axillobrachialis
4. M. deltoideus
   
   • Reflected
5. V. omobrachialis
   
   • From v. omobrachialis

• * M. cleidobrachialis

Question 21

Lateral view of the brachium and antebrachium

Answer 21

1. N. radialis
2. M. triceps brachii
   
   • Innervated by n. radialis
   • N. radialis divides into deep and superficial branches
3. N. radialis profundus
   
   • Innervating craniolateral antebrachial muscles
4. N. radialis, medial branch
   
   • Supply skin of the cranial antebrachium and dorsal manus
5. N. radialis, latral branch
   
   • Supply skin of the cranial antebrachium and dorsal manus
6. A. brachialis superficialis

• * M. brachialis