Lecture 11: Brachium and Elbow

Question 1

The brachium is portion of thoracic limb between

Answer 1

Shoulder girdle and elbow

Question 2

Movement of the arm is achieved by muscles that move the _____

Answer 2

Gleno-numeral joint`

Question 3

What muscles extend the GH joint

Answer 3

Triceps brachi, supraspinatus, brachiocephalicus

Question 4

What muscles flex the GH joint

Answer 4

Biceps brachii, teres major, teres minor, latissimus dorsi, pectoralis profundus

Question 5

What muscles abduct the GH joint

Answer 5

Infraspinatus

Question 6

What muscles adduct the GH joint

Answer 6

Pectoral muscles, coracobrachialis, subscapularis

Question 7

What are the three joints of the elbow

Answer 7

Humero-radial, humero-ulnar, radio-ulnar

Question 8

What does the trochlea of the humerus sit on

Answer 8

Ulna

Question 9

What does capitulum of humerus sit on

Answer 9

Radius

Question 10

What ligaments support the elbow

Answer 10

Medial and lateral collateral ligaments, annular ligament of radius, oblique ligament

Question 11

Flexion and extension of the elbow is permitted along a Sagittal plane via what joints

Answer 11

Humero-radial and humero-ulnar

Question 12

Role of collateral ligaments

Answer 12

Prevent excessive abduction and adduction

Question 13

Role of oblique ligament

Answer 13

Prevents over-extension of elbow

Question 14

Pronation/supination

Answer 14

Distal radius around the ulna and requires rotation of numeral head around proximal radio-ulnar joint

Question 15

Role of annular ligament of radius

Answer 15

Permits pronation and supination

Question 16

What artery supplies the flexor compartment of the arm

Answer 16

Brachial

Question 17

What nerve innervate the flexor compartment of the arm

Answer 17

Musculocutaneous

Question 18

What are the flexor muscles of the arm

Answer 18

Biceps brachii, brachialis

Question 19

What is the artery that supplies the extensors of the arm

Answer 19

Deep brachial artery

Question 20

What nerve innervates the extensor compartment of the arm

Answer 20

Radial

Question 21

What muscles are in the extensor compartment of the arm

Answer 21

Triceps brachii (long, lateral, medial, and accessory), tensor fascia antebrachium, and anconeus

Question 22

OINA for long head of triceps brachii

Answer 22

O:infraglenoid tubercle
I: olecranon process of ulna
N: radial
A: extend arm and forearm

Question 23

OINA for lateral head of triceps brachii

Answer 23

O: space between teres minor and deltoid
I: olecranon process of ulna
N: radial
A: extend arm and forearm

Question 24

OINA for medial head of triceps brachii

Answer 24

O: space between coracobrachialis and teres minor
I: olecranon process of ulna
N: radial
A: extend arm and forearm

Question 25

OINA for accessory head of triceps brachii

Answer 25

O: caudal aspect of humerus I: olecranon process of ulna N: radial A: extend arm and forearm

Question 26

What is the result of avulsion fracture of olecranon

Answer 26

Detachment of triceps, lose ability to extend elbow, dropped elbow appearance

Question 27

OINA for Biceps Brachii

Answer 27

O: Supraglenoid tubercle I: two insertions: 1. Deep insertion: radial tuberosity and medial ulnar, 2: superficial insertion: antebrachium fascia (lacertus fascia) N: musculocutaneous A: flex arm and forearm

Question 28

OINA for brachialis

Answer 28

O: caudal aspect of proximal humerus I: ulnar tuberosity N: musculocutaneous A: flex arm and forearm

Question 29

What is the fibrous band ion horse that joints the tendons of origin and insertion of biceps brachii

Answer 29

Internal tendon/central tendon

Question 30

What is the role of internal/central tendon

Answer 30

At faster gaits the force necessary for rapid protraction of forelimb is beyond power of muscle so central tendon enables the muscle to store energy when stretched during support phase and then is rapidly released to accelerate forward movement of limb

Question 31

What is the lacertus fibrosus

Answer 31

Tendon that splits away from internal/central tendon

Question 32

What muscles protect the brachial plexus well

Answer 32

Serratus ventralis and pectoral muscles

Question 33

Where does the radial nerve originate

Answer 33

C7-T1

Question 34

What muscles does the radial nerve innervate

Answer 34

Triceps brachii, aconeus and tensor fascia antebrachium

Question 35

What is the path of the radial nerve

Answer 35

Runs distally within the arm, caudal to brachial artery. Dives between long and medial head of triceps and follows groove of humerus. Enters the cranial lateral aspect of limb

Question 36

Where does the musculocutaneous nerve originate

Answer 36

C7-C8

Question 37

What muscles does the musculocutaneous innervate

Answer 37

Biceps brachii, brachialis, coracobrachialis

Question 38

What is the path of musculocutaneous nerve in dogs

Answer 38

Gives proximal branch to coracobrachialis, communicating branch passes distocaudally to median nerve in distal third of arm. Nerve passes under terminal part of biceps and divides into branch to brachialis and medial cutaneous nerve of forearm

Question 39

What is the musculocutaneous path in ungulates

Answer 39

Nerve loops around the axillary artery to join median nerve, in brachium separates from median

Question 40

What is the path of musculocutaneous nerve in horses

Answer 40

Cutaneous branch extends beyond carpus to metacarpophalangeal joint/fetlock

Question 41

Where does median nerve originate

Answer 41

C8-T1

Question 42

What muscles does the median nerve innervate

Answer 42

Flexor muscles carpus and digits

Question 43

What is path of median nerve in dogs

Answer 43

Travels does the medial surface of the arm caudal to the axillary and then brachial artery. Enters the forearm over the medial collateral ligament of the elbow joint

Question 44

Where does the ulnar nerve originate

Answer 44

C8-T1

Question 45

What muscles does the ulnar nerve innervate

Answer 45

Most of the flexor muscles of the carpus and digits

Question 46

What is the path of the ulnar nerve

Answer 46

Travels down the brachium beside or united with median nerve. Splits off towards olecranon to cross the caudal aspect of the elbow joint-wraps around medial epicondyle of humerus