Week 1: Muscles of the Thoracic Limb (Origins, Insertions, Actions)

Question 1

Two parts of the superficial pectoral

Answer 1

pectoralis transversus

pectoralis descendens

Question 2

Origin of the superficial pectoral (2)

Answer 2

First three sternebrae

median fibrous raphe at the ventral midline

Question 3

Insertion of the superficial pectoral

Answer 3

Crest of the greater tubercle of the humerus

Question 4

Action of the superficial pectoral (2)

Answer 4

Adduct limb (non-weight bearing)
prevent abduction of limb (weight bearing)

Question 5

Origin of the deep pectoral (2)

Answer 5

Ventral part of the sternum

Median fibrous raphe at the ventral midline

Question 6

Insertion of the deep pectoral (2)

Answer 6

Lesser tubercle of the humerus (major portion of insertion)

Greater tubercle and crest of the humerus via aoneurosis

Question 7

Action of the deep pectoral (3)

Answer 7

Pull trunk cranially when limb is advanced and fixed
Extend shoulder
Draw limb caudally when not supporting weight

Question 8

Two parts of brachiocephalicus

Answer 8

cleidobrachialis and cleidocephalicus

Question 9

Two parts of the cleidocephalicus

Answer 9

cleidomastoideus and cleidocervalicus

Question 10

Brachiocephalicus origin

Answer 10

clavicular intersection

Question 11

Brachiocephalicus insertion (3)

Answer 11

Distal end of cranial humerus
Middorsal fibrous raphe of the neck
Mastoid process of the temporal bone

Question 12

Brachiocephalicus action (3)

Answer 12

Advance the limb
Extend the shoulder
Draw head to the side of the neck

Question 13

Lymph node associated with the omotransversarius

Answer 13

The superficial cervical lymph node

also called the pre-scapular lymph node

Question 14

Omotransversarius origin

Answer 14

Wing (transverse process) of the atlas (cervical vertebrae 1)

Question 15

Omotransversarius insertion

Answer 15

Distal end of the spine of the scapula

Question 16

Omotransversarius action (2)

Answer 16

Advance the limb

Flex the neck laterally

Question 17

Two parts of the trapezius

Answer 17

Cervical trapezius

Thoracic trapezius

Question 18

Trapezius origin (2)

Answer 18

Median fibrous raphe of the neck

Supraspinous ligament

Question 19

Trapezius insertion

Answer 19

Spine of the scapula

Question 20

Trapezius action (2)

Answer 20

elevate and abduct limb

Question 21

Three parts of the rhomboideus

Answer 21

rhomboideus capitis
rhomboideus cervicis
rhomboideus thoracis

Question 22

Rhomboideus origin (3)

Answer 22

Base of skull (nuchal crest of occipital bone)
Median fibrous raphe of neck
Spinous processes of thoracic vertebrae

Question 23

Insertion of rhomboideus

Answer 23

Dorsal border of the scapula

Question 24

Action of the rhomboideus (2)

Answer 24

Elevate limb

Draw scapula against trunk

Question 25

Latissimus dorsi origin (2)

Answer 25

Thoracolumbar fascia

Last few ribs

Question 26

Latissimus dorsi insertion

Answer 26

Teres major tuberosity of the humerus via the teres major tendon

Question 27

Latissimus dorsi action (2)

Answer 27

draw the limb caudally

Flex shoulder

Question 28

Serratus ventralis can be referred to as what kind of muscle

Answer 28

sling muscle

Question 29

Origin of the serratus ventralis (2)

Answer 29

Ribs

Transverse processes of cervical vertebrae

Question 30

Insertion of serratus ventralis

Answer 30

Serrated face of the scapula

Question 31

Action of the serratus ventralis (2)

Answer 31

Support trunk

Depress scapula

Question 32

Origin of the deltoideus

Answer 32

Spine and acromion of the scapula

Question 33

Insertion of the deltoideus

Answer 33

Deltoid tuberosity of the humerus

Question 34

Action of the deltoideus

Answer 34

Flex shoulder

Question 35

Infraspinatus muscle has what bursa associated with it?

Answer 35

Subtendinous synovial bursa

Question 36

Infraspinatus origin

Answer 36

infraspinous fossa of the scapula

Question 37

Infraspinatus insertion

Answer 37

lateral side of the greater tubercle of the humerus

Question 38

Infraspinatus action (4)

Answer 38

Laterally stabilizes the shoulder (prevents medial rotation while weight bearing)
Abduct and laterally rotate shoulder
Assists other muscles in the extension or flexion of the shoulder