Extrinsic Muscles Of The Thoracic Limb

Question 1

> > Origin – the first 2 sternebrae and usually part of the third

> > Insertion – the whole crest of the greater tubercle

> > Action – to adduct the limb when it is not bearing weight or to prevent the limb from being abducted when bearing weight

> > Innervation – Cranial pectoral nerves (C7, C8)

Answer 1

Superficial pectoral

Question 2

Origin of Superficial pectoral

Answer 2

the first 2 sternebrae and usually part of the third

Question 3

**Insertion of Superficial pectoral

Answer 3

the whole crest of the greater tubercle

Question 4

**Action of Superficial pectoral

Answer 4

• to adduct the limb when it is not bearing weight
• to prevent the limb from being abducted when bearing weight

Question 5

Innervation of Superficial pectoral

Answer 5

Cranial pectoral nerves (C7, C8)

Question 6

Origin – the ventral part of the sternum and the fibrous raphe between fellow muscles; the deep abdominal fascia in the region of the xiphoid cartilage.

Answer 6

Deep pectoral

Question 7

Insertion – the major portion partly muscular, partly tendinous on the lesser tubercle of the humerus; an aponeurosis to the greater tubercle and its crest; the caudal part to the medial brachial fascia.

Answer 7

Deep pectoral

Question 8

Action – to pull the trunk cranially when the limb is advanced and fixed; to extend the shoulder; to draw the limb caudally when it is not supporting weight

Question 9

Innervation – caudal pectoral nerves (C8, T1)

Answer 9

Deep pectoral

Question 11

Action – to advance the limb; to extend the shoulder and draw the neck and head to the side.
Innervation – accessory nerve, and ventral branches of cervical nerves.

Answer 11

Braciocephalicus (3 muscles)

Question 12

• muscle distal to the clavicular tendon and attaches to the arm

Answer 12

Cleidobrachialis

Question 13

• Attached to the skull
• attached to the clavicular tendon

Answer 13

Cleidocephalicus pars mastoideus

Question 14

• more lateral in orientation
• Much more superficial
• extends from the clavicular tendon to the dorsum of the neck

Answer 14

Cleidocephalicus pars cervicalis

Question 15

Origin – the first sternebrae or manubrium

Answer 15

Sternocephalicus (4 muscles)

Question 16

Insertion – the mastoid part of the temporal bone and the nuchal crest of the occipital bone.

Answer 16

Sternocephalicus (4 muscles)

Question 17

Action – to draw head and neck to the side.

Answer 17

Sternocephalicus

Question 18

Innervation – accessory nerve and the ventral branches of cervical nerves.

Answer 18

Sternocephalicus

Question 19

Attachment – the distal end of the spine of scapula; cranially, the wing of the atlas.
Action – to advance the limb or flex the neck laterally.
Innervation – accessory nerve

Answer 19

Omotransversarius

Answer 20

Trapezius (divided into 2 muscles)