Extrinsic Thoracic Limb Muscle Actions

Question 1

Superficial Pectoral m.

Answer 1

When not bearing weight - adduct the limb
When bearing weight - prevents limb from being abducted

Question 2

Deep Pectoral m.

Answer 2

When limb is advanced and fixed - pull the trunk cranially
When not bearing weight - draw the limb caudally
Adduct the limb
Support the trunk

Question 3

Brachiocephalicus m.

Answer 3

Advance the limb
Extend shoulder jt.
Draw the neck and head to the side

Question 4

Sternocephalicus m.

Answer 4

Draw neck and head to the side

Question 5

Sternohyoideus m.

Answer 5

Draw the tongue and larynx caudally

Question 6

Sternothyroideus m.

Answer 6

Draw the larynx and tongue caudally

Question 7

Omotransversarius m.

Answer 7

Advance the limb
Flex the neck laterally

Question 8

Trapezius m.

Answer 8

T. Cervicis - draw the scapula craniodorsally
T. Thoracis - draw the scapula caudodorsally
Acting together - elevate and abduct the limb

Question 9

Rhomboideus m.

Answer 9

Elevate the forelimb (scapula)
Draw the scapula against the trunk

Question 10

Latissimus dorsi m.

Answer 10

Draw the limb caudally
Flex the shoulder jt.

Question 11

Serratus ventralis m.

Answer 11

Support the trunk by slinging the body between forelimbs (along with deep pectoral m.)
Depress the scapula