Forelimb Musculoskeletal Structure Flashcards
What muscle is the clavicle embedded in?
Embedded in the brachiocephalicus muscle, cranial to the shoulder joint
glenoid cavity
- distal end of the scapula
- articulates with the head of the humerus
scapular spine
ends at the acromion
- lateral surface of the scapula
acromion
a process of the distal end of the spine
- NOT PRESENT in horse & pig
supraspinous fossa*
cranial to the spine
infraspinous fossa*
caudal to the spine
scabscapular fossa*
most of the medial surface
supraglenoid tubercle*
process near the cranial aspect of the glenoid cavity
infraglenoid tubercle*
process near the caudal aspect of the glenoid cavity
greater tubercle*
large process craniolateral to the head
lesser tubercule*
process on the medial side of the head
intertubercular groove
between and the greater & lesser tubercule
deltoid tuberosity*
large tuberosity on the the lateral side of the humerus
humeral condyle
the entire distal extremity of the humerus
- includes trochlea & capitulum
olecranon fossa*
the caudal aspect that receives the olecranon of the ulna
radial fossa*
cranial aspect that receives the head of the radius
trochlea*
medial portion of the condyle (larger); articular surface
capitulum*
the lateral portion of the condyle (smaller); the articular surface
supratrochlear foramen
the hole between the olecranon fossa & radial fossa
- found in the dog
supracondylar foramen
- opening in the medial epicondyle of the CAT
- median nerve & brachial artery ass through it
styloid process of the ulna*
pointed distal end of the ulna
styloid process of the radius*
the distal end, medial of the radius
olecranon
the proximal part of the ulna forms the “point” of the elbow
- attachment site of the triceps brachii muscle
trochlear notch
articulates with the trochlea of the humerus
- proximal end, half-moon shaped, concave articular surface
anconeal process
proximal end of the trochlear notch
coronoid process
distal end of the trochlear notch
- medial & lateral divisons
interosseous space
between the ulna & radius
where does the extensors and flexor muscles of the forearm attach to the humerus?
extensor muscles attach -> lateral epicondyle
flexor muscles attach -> medial epicondyle
what species of animal has a supracondylar foramen?
cat
what species of animal has a supratrochlear foramen?
dog
what species of animal has an intermediate tubercle?
horse
shin splints*
difference between pronation & supination? why are horses and ruminants not capable of either?
pronation: to rotate outward (thumbs go inward to downward)
supination: to rotate inward (thumbs go inward to outward)
the typical carpal pattern of the 8 bones? What is the difference between species?
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
what are the carpal structures that form the border of the carpal canal?
- accessory carpal bone (laterally)
- other carpal bones (dorsally)
- flexor retinaculum (palmar)
what 2 nerves run through the carpal canal?
ulnar & median nerves
which digits are weighting bearing for the horse & pig?
digits III & IV
what is the skeletal structure of the horses’ forelimbs?
WORK ON THIS ONE
- fetlock joint
- pastern joint
- coffin joint
- navicular bursa
what ligaments are responsible for keeping claws retracted in cats?
Dorsal ligaments (3, carnivores):
keep the claw retracted in cats
what ligaments prevent abnormal separation of the two digits in cattle?
Proximal/distal interdigital ligaments (cow):
prevents abnormal separation of the two digits
difference between extrinsic & intrinsic muscles?
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
What superficial muscle originates on the spine of the scapula and inserts on the dorsal neck/thorax?
trapezius muscle
What superficial muscle originates on the spine of the scapula and extends to the atlas? Is it proximal or distal to the trapezius?
Omotransversarius:
- proximal to the trapezius muscle
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)?
Brachiocephalicus
i. Cleidobrachialis (2’)
ii. Cleidocephalicus (2)
What extrinsic muscle of the shoulder originates on the dorsal border of the scapula and inserts on the dorsal neck/thorax/skull?
rhomboideus
What extrinsic muscle of the shoulder supports the weight of the trunk?
Serratus ventralis
What two muscles make up the “brisket” in beef cattle?
Deep pectoral & superficial pectoral
Is the teres major on the caudal or cranial aspect of the limb?
Caudal aspect of the limb
i. Flexes the shoulder
Is the subscapularis on the lateral or medial aspect of the limb?
Medial aspect
i. Abducts the shoulder
What are the 4 heads of the triceps brachii? What is its action on the elbow?
Extends the elbow/flexes the shoulder
i. Caput longum
ii. Caput laterale
iii. Caput mediale
iv. Caput accessorium
Is the biceps brachii on the cranial or caudal aspect of the humerus? What is its action on the elbow?
Proximocaudal surface of the humerus. And it flexes the elbow
Where do the extensor muscles of the carpus and digit originate?
Originate on/near the lateral epicondyle of the humerus
What is the most medial of the dorsolateral muscles of the forearm?
Extensor carpi radialis
Where does the common digital extensor insert?
Long muscle from the humerus to the digital phalanges (tendon for each digit)
Where does the lateral digital extensor insert?
From the proximal radius to the middle phalanges
Where do the flexor muscles of the carpus and digit originate? Are they caudal or craniolateral?
Originate the lateral epicondyle of the humerus
i. craniolateral
Which of the caudal antebrachial muscles are innervated by the median nerve and is the most medial of the group?
Flexor carpi radialis
i. Flex the carpus & digits
Know the structures of the stay apparatus of the equine forelimb. Know how they function to stabilize the limb.
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
where are the extensors and flexor muscles of the forearm attached to the humerus?
extensor muscles -> sternum to the humerus
flexor muscles ->
