Thoracic Limb Extrinsic Muscles

Question 1

What are the two functions of the thoracic limb?

Answer 1

1. Weight Bearing

2. Propulsion

Question 2

What sits in the inter tubercular groove?

Answer 2

The biceps brachia tendon

Question 3

Which is bigger: the lateral epicondyle or the medial epicondyle?

Answer 3

Medial

Question 4

Which species does not have the supratrochlear foramen and what does it have instead? What passes through this?

Answer 4

• The cat
• supracondylar formamen
• brachial artery and the median nerve

Question 5

The trochlea is (Medial/lateral) and articulates with what? The capitulum is (Medial/lateral) and articulates with what?

Answer 5

• Medial, radius and ulna

- Lateral, articulates with radius

Question 6

Which structures of the radius are in charge of weight support?

Answer 6

Head, trochlea, and styloid process

Question 7

What is the function of the ulna?

Answer 7

Muscular attachment

Question 8

Which parts of the ulna are prone to fracture?

Answer 8

• anconeal process

- medial and lateral coronoid processes

Question 9

The _____ ______ is the projection on the distal end of the ulna.

Answer 9

Styloid Process

Question 10

What are the four anatomic areas of the manus?

Answer 10

1. Carpal bones (proximal carpal (radial, ulnar accessory) and distal carpal (first, second, third, fourth))
2. Metacarpal bones (first, second, third, fourth, fifth)
3. 5 digits (each with three phalanges: Proximal, middle, distal)
4. Sesamoid bones (Between metacarpal bones and phalanges)

Question 11

The middle phalanx is absent in digit ____.

Answer 11

one

Question 12

_____ ______ are small bones embedded in tendons or joints that reduce friction during movement.

Answer 12

-Sesamoid bones

Question 13

The distal phalanx is composed of the _____ ____ (a thin shelf, circle around the base), the ____ _____ (conical extension of the distal phalanx), and the _____ ____, which is the dorsal part of the base.

Answer 13

• Ungual crest
• Ungual process
• Extensor process

Question 14

The extensor process is the insertion site for the _____ ____ ____ muscle on digits two through five.

Answer 14

common digital extensor

Question 15

The _____ _____ of the ______ is the longitudinal fibrous septum between the right and left epaxial muscles. It serves as an attachment site for many ____ muscles.

Answer 15

• Median Raphne of the Neck

- Cervical

Question 16

The ____ ____ is the deep fascia of the trunk. It arises from the ______ ligaments and spines of the ____ and ____ vertebrae. It covers the _____ of the vertebrae and serves as an attachment site for many _____.

Answer 16

• Thoracolumbar fascia
• supraspinous
• thoracic
• lumbar
• muscles
• muscles

Question 17

Extrinsic muscles of the of the thoracic limb join to the trunk by _____, not by the conventional joint. What is the clinical significance of this?

Answer 17

• Synsarcosis

- Amputation of the forelimb is performed by simply transecting the extrinsic muscles to remove the limb

Question 18

The superficial pectoral muscle is innervated by the ____ ____ nerve. What are the two components? What is their function?

Answer 18

• cranial pectoral

- Composed of the descending pectoral muscle and the transverse pectoral muscle, which function in adduction

Question 19

The deep pectoral muscle is innervated by the _____ ____ nerve. What is its function?

Answer 19

• Caudal pectoral

- To pull the trunk cranially

Question 20

The brachiocephalicus muscle is innervated by the what nerve(s). What is this muscle’s function?

Answer 20

• accessory
• ventral branches of the cervical spinal
• To advance the limb

Question 21

What are the parts of the brachiocephalicus muscle? What is the intersection called?

Answer 21

• Cleidobrachialis
• Cleidocervicalis (pars cervicalis and the pars mastoideus)
• Clavicular Intersection

Question 22

The sternocephalicus is innervated by what nerve(s). What is this muscle’s functions? What are the two parts?

Answer 22

• Accessory
• Cervical spinal
• Draws the head and neck to the side
• Composed of the mastoid and occipital parts

Question 23

The omotransversarius is innervated by what nerve(s). What is its function?

Answer 23

• Accessory

- Advance the limb

Question 24

The trapezius is innervated but what nerve(s). What are its parts and functions?

Answer 24

• Accessory
• Composed of the cervical and thoracic parts
• Elevates/abducts the limb

Question 25

The rhomboideus is innervated by what nerve(s). What are its parts and functions?

Answer 25

• cervical and thoracic spinal
• Capitis, cervicis, and thoracic parts
• Elevates the limb

Question 26

The _____ muscle lies beneath the trapezius.

Answer 26

Rhomboideus

Question 27

The lattisimus Dorsi is innervated by what nerve(s). What is its function?

Answer 27

• Thoracodorsal

- Digging

Question 28

The serratus ventralis muscle is innervated by what nerve(s). What are its parts and functions?

Answer 28

• Ventral branches of the cervical spinal
• long thoracic
• Two parts: cervicis and thoracis
• Depress the scapula

Question 29

THe _____ _____ is not an extrinsic muscle, it is a thin sheet of muscle underlying the skin and covering the walls of the thorax and abdomen. It is innervated by the _____ _____ nerve and what is its function?

Answer 29

• Cutaneous trunci
• Lateral thoracic
• Twitches the skin

Question 30

What is the clinical relevance of learning the thoracic extrinsic muscles?

Answer 30

It allows you to perform amputation of the thoracic limb