Forelimb Musculoskeletal Structure

Question 1

What muscle is the clavicle embedded in?

Answer 1

Embedded in the brachiocephalicus muscle, cranial to the shoulder joint

Question 2

glenoid cavity

Answer 2

• distal end of the scapula
• articulates with the head of the humerus

Question 3

scapular spine

Answer 3

ends at the acromion
- lateral surface of the scapula

Question 4

acromion

Answer 4

a process of the distal end of the spine
- NOT PRESENT in horse & pig

Question 5

supraspinous fossa*

Answer 5

cranial to the spine

Question 6

infraspinous fossa*

Answer 6

caudal to the spine

Question 7

scabscapular fossa*

Answer 7

most of the medial surface

Question 8

supraglenoid tubercle*

Answer 8

process near the cranial aspect of the glenoid cavity

Question 9

infraglenoid tubercle*

Answer 9

process near the caudal aspect of the glenoid cavity

Question 10

greater tubercle*

Answer 10

large process craniolateral to the head

Question 11

lesser tubercule*

Answer 11

process on the medial side of the head

Question 12

intertubercular groove

Answer 12

between and the greater & lesser tubercule

Question 13

deltoid tuberosity*

Answer 13

large tuberosity on the the lateral side of the humerus

Question 14

humeral condyle

Answer 14

the entire distal extremity of the humerus
- includes trochlea & capitulum

Question 15

olecranon fossa*

Answer 15

the caudal aspect that receives the olecranon of the ulna

Question 16

radial fossa*

Answer 16

cranial aspect that receives the head of the radius

Question 17

trochlea*

Answer 17

medial portion of the condyle (larger); articular surface

Question 18

capitulum*

Answer 18

the lateral portion of the condyle (smaller); the articular surface

Question 19

supratrochlear foramen

Answer 19

the hole between the olecranon fossa & radial fossa
- found in the dog

Question 20

supracondylar foramen

Answer 20

• opening in the medial epicondyle of the CAT
• median nerve & brachial artery ass through it

Question 21

styloid process of the ulna*

Answer 21

pointed distal end of the ulna

Question 22

styloid process of the radius*

Answer 22

the distal end, medial of the radius

Question 23

olecranon

Answer 23

the proximal part of the ulna forms the “point” of the elbow
- attachment site of the triceps brachii muscle

Question 24

trochlear notch

Answer 24

articulates with the trochlea of the humerus
- proximal end, half-moon shaped, concave articular surface

Question 25

anconeal process

Answer 25

proximal end of the trochlear notch

Question 26

coronoid process

Answer 26

distal end of the trochlear notch - medial & lateral divisons

Question 27

interosseous space

Answer 27

between the ulna & radius

Question 28

where does the extensors and flexor muscles of the forearm attach to the humerus?

Answer 28

extensor muscles attach -> lateral epicondyle flexor muscles attach -> medial epicondyle

Question 29

what species of animal has a supracondylar foramen?

Answer 29

cat

Question 30

what species of animal has a supratrochlear foramen?

Answer 30

dog

Question 31

what species of animal has an intermediate tubercle?

Answer 31

horse shin splints*

Question 32

difference between pronation & supination? why are horses and ruminants not capable of either?

Answer 32

pronation: to rotate outward (thumbs go inward to downward) supination: to rotate inward (thumbs go inward to outward)

Question 33

the typical carpal pattern of the 8 bones? What is the difference between species?

Answer 33

carpal bones: 1. proximal row: radial, intermediate, ulnar, accessory 2. distal row: 1st, 2nd, 3rd, 4th carpal bones - 7 small, irregular bones (carnivore), fused radio intermediate bone - pig = 8 bones - horse = 7 - 4 in proximal row - 3 in distal row

Question 34

what are the carpal structures that form the border of the carpal canal?

Answer 34

- accessory carpal bone (laterally) - other carpal bones (dorsally) - flexor retinaculum (palmar)

Question 35

what 2 nerves run through the carpal canal?

Answer 35

ulnar & median nerves

Question 36

which digits are weighting bearing for the horse & pig?

Answer 36

digits III & IV

Question 37

what is the skeletal structure of the horses' forelimbs?

Answer 37

WORK ON THIS ONE - fetlock joint - pastern joint - coffin joint - navicular bursa

Question 38

what ligaments are responsible for keeping claws retracted in cats?

Answer 38

Dorsal ligaments (3, carnivores): keep the claw retracted in cats

Question 39

what ligaments prevent abnormal separation of the two digits in cattle?

Answer 39

Proximal/distal interdigital ligaments (cow): prevents abnormal separation of the two digits

Question 40

difference between extrinsic & intrinsic muscles?

Answer 40

extrinsic muscles: Muscles that attach the forelimb to some other part of the body (head, neck or trunk) intrinsic muscles: Muscles having both attachments on the limb

Question 41

What superficial muscle originates on the spine of the scapula and inserts on the dorsal neck/thorax?

Answer 41

trapezius muscle

Question 42

What superficial muscle originates on the spine of the scapula and extends to the atlas? Is it proximal or distal to the trapezius?

Answer 42

Omotransversarius: - proximal to the trapezius muscle

Question 43

What long flat superficial muscle extends from the head/neck to the arm? What are the 2 divisions of this muscle (as demarcated by the clavicular insertion)?

Answer 43

Brachiocephalicus i. Cleidobrachialis (2’) ii. Cleidocephalicus (2)

Question 44

What extrinsic muscle of the shoulder originates on the dorsal border of the scapula and inserts on the dorsal neck/thorax/skull?

Answer 44

rhomboideus

Question 45

What extrinsic muscle of the shoulder supports the weight of the trunk?

Answer 45

Serratus ventralis

Question 46

What two muscles make up the “brisket” in beef cattle?

Answer 46

Deep pectoral & superficial pectoral

Question 47

Is the teres major on the caudal or cranial aspect of the limb?

Answer 47

Caudal aspect of the limb i. Flexes the shoulder

Question 48

Is the subscapularis on the lateral or medial aspect of the limb?

Answer 48

Medial aspect i. Abducts the shoulder

Question 49

What are the 4 heads of the triceps brachii? What is its action on the elbow?

Answer 49

Extends the elbow/flexes the shoulder i. Caput longum ii. Caput laterale iii. Caput mediale iv. Caput accessorium

Question 50

Is the biceps brachii on the cranial or caudal aspect of the humerus? What is its action on the elbow?

Answer 50

Proximocaudal surface of the humerus. And it flexes the elbow

Question 51

Where do the extensor muscles of the carpus and digit originate?

Answer 51

Originate on/near the lateral epicondyle of the humerus

Question 52

What is the most medial of the dorsolateral muscles of the forearm?

Answer 52

Extensor carpi radialis

Question 53

Where does the common digital extensor insert?

Answer 53

Long muscle from the humerus to the digital phalanges (tendon for each digit)

Question 54

Where does the lateral digital extensor insert?

Answer 54

From the proximal radius to the middle phalanges

Question 55

Where do the flexor muscles of the carpus and digit originate? Are they caudal or craniolateral?

Answer 55

Originate the lateral epicondyle of the humerus i. craniolateral

Question 56

Which of the caudal antebrachial muscles are innervated by the median nerve and is the most medial of the group?

Answer 56

Flexor carpi radialis i. Flex the carpus & digits

Question 57

Know the structures of the stay apparatus of the equine forelimb. Know how they function to stabilize the limb.

Answer 57

a. Collateral ligaments b. Tendon of the extensor carpi radialis muscle c. Prevent hyperextension of the fetlock & pastern d. Biceps brachii has more connective tissue i. Lacertus fibrosus

Question 58

where are the extensors and flexor muscles of the forearm attached to the humerus?

Answer 58

extensor muscles -> sternum to the humerus flexor muscles ->