L12: structure and function of forelimb joints

simple joint

joint has articulations between 2 articulating bones

compound joint

joint has more than 2 articulating bones

what are the further classifications of fibrous joints?

1. syndesmosis

2. sutures

3. gomphosis

syndesmosis joint

ligamentous joint united by fibrous tissue that permits only slight movement

where are syndesmosis joints present?

1. coastal cartilage on coastal arch

2. between radius and ulna

sutures joint

fibrous joint between bones of the skull

gomphosis joint

specialized articulation in the teeth with the mandible and maxilla

what are the types of cartilagenous joints?

1. synchrondosis

2. symphyses

what type of cartilage makes up synchrondosis joints?

hyaline cartilage

what is an example of a synchrondosis joint?

growth plate

what cartilage makes up symphyses joint?

fibrocartilage

where can symphyses joints be found in the body?

1. between pelvic bone and pelvic symphisis

2. mandibular symphysis

3. between vertebra

what is only type of joint with a joint cavity?

synovial joint

what is the only joint that is freely moveable?

synovial joint

what is another name for the elbow joint?

cubital

what is another name for the metocarpophalangeal joint?

fetlock

what is another name for the proximal interphalangeal joint?

pastern

what is another name for the distal interphalangeal joint?

coffin

MCQ: how are joints in dogs primarily classified?

function and structure

MCQ: what is an example of a fibrous joint in dogs?

sutures of the skull

what is 1?

cannon bone

what is 2?

lateral splint bone

what is 3?

proximal sesamoid bone

what is 4?

proximal phalanx (long pastern bone)

what is 5?

middle phalanx (short pastern bone)

what is 6?

distal phalanx (coffin bone)

what type of joint attaches the forelimb to the trunk?

synsarcosis

which limb bears more weight and is involved more in the animal landing?

forelimb

reflex angle

more than 180 degrees

how do muscles prevent overextension or overflexion of a limb>

via equilibrium of flexors and extensors

what structure in the limb prevents the opposite action?

ligaments

what will ligaments on the flexor surface prevent?

hyperextension of the limb

active range of motion (AROM)

the movement a joint can perform when the animal moves it voluntarily using their own muscles

passive range of motion (PROM)

movement achieved when an external force (vet or therapist) moves the joint without muscle effort from the animal

what bones are involved with the shoulder joint?

1. glenoid cavity of scapula

2. head of proximal humerus

what type of joint is the shoulder joint?

simple synovial ball and socket joint

glenoid lip

fibrocartilaginous rim along the articular cartilage that deepens and widens the glenoid cavity

where does the joint cavity of the shoulder joint extend?

extends medially and laterally

bicipital bursa

extension of the shoulder joint in dogs

what is the clinical significance of the bicipital bursa?

due to connection to shoulder, you can inject into shoulder joint and it will reach bicep bursa

where is the joint cavity of the shoulder joint?

from the glenoid lip to the neck of the humerus

what are the ligaments of the shoulder joint?

1. transverse humeral ligament

2. lateral and medial glenohumeral ligaments

what is the function of the transverse humeral ligament?

hold the tendon of the bicep in the intertubercular groove

what are movements of the shoulder joint in quadrupeds limited to?

flexion and extension due to muscles surrounding shoulder joint

what movement helps with shock absorption of the shoulder?

gliding of glenoid cavity and humeral head

what is the function of the active ligaments of the shoulder

provide stability

what assists the active ligaments of the shoulder laterally?

teres minor

what assists the active ligaments of the shoulder medially?

teres major

what makes up the active ligaments of the shoulder>

tendons of the:

1. subscapularis muscle

2. supraspinatus muscle

3. infraspinatus muscle

what causes sweeny shoulder in horses?

damage to the suprascapular nerve

which shoulder muscles atrophy during sweeny shoulder?

1. infraspinatus muscles

2. supraspinatus muscles

MCQ: what feature is always present in all synovial joints?

articular capsule

MCQ: which is an additional feature of a synovial joint?

ligament

what bones are involved with the cubital joint?

1. distal humerus

2. proximal radius and ulna

what type of joint is the cubital joint?

compound synovial condylar joint

what are the component articulations of the cubital joint?

1. humeroradial joint

2. humeroulnar joint

3. proximal radioulnar joint

what is the olecranon tuberosity also known as?

point of the elbow

what are the components of the cubital joint capsule?

1. cranial joint capsule

2. lateral joint capsule

3. medial joint capsule

what are the ligaments of the cubital joint?

1. collateral ligaments

2. oblique ligament

3. annular ligament of the radius

4. olecranon ligament

what is the function of the collateral ligaments in the cubital joint?

1. stabilize elbow joint

2. prevent valgus and varus

what is the function of the oblique ligament of the cubital joint?

prevent overextension of elbow joint

what is the function of the annular ligament in the cubital joint?

hold radius and ulna together (absent in ruminants)

what is the function of the olecranon ligament of the cubital joint?

prevent overflexion of the elbow joint

what species is the olecranon ligament of the cubital joint present in?

small animals only

which collateral ligament of the cubital joint is branched in the horse?

medial collateral ligament

what is the lateral collateral ligament in the horse a component of?

the stay apparatus

MCQ: which ligament prevents bending of the cubital joint outward (laterally) or inward (medially)?

collateral ligaments

what lesions are associated with elbow dysplasia?

1. un-united anconeal process of the ulna

2. fragmentation of the medial coronoid process of ulna

3. osteochondrosis of medial aspect of humeral condyle

which ligament in any joint restrict the movement to extension and flexion only?

lateral and medial collateral ligaments

what are the functional digits in the pig?

2 and 3

what is the functional digit in bovine?

digits 3 and 4

what is the most stressed joint in the forelimb of horses?

fetlock

how many functional digits does the dog have?

4 (digits 2-5)

what bones are involved in the carpal joint of the dog?

1. distal ends of radius and ulna

2. 7 carpal bones

3. 5 metacarpal bones

what type of joint is the carpal joint?

compound synovial hinge joint

what bones are involved in the carpal joint of the horse?

1. distal end of radius

2. 7 carpal bones

3. 3 metacarpal bones

what are the joint articulations of the carpal joint?

1. antebrachiocarpal joint cavity

2. middle carpal joint cavity

3. carpometacarpal joint cavity

antebrachiocarpal joint

isolated joint cavity present between the antebrachium and carpus

which joint cavities communicate with one another in the carpus?

middle carpal joint cavity and carpometacarpal joint cavity

how many injections would be needed for the carpus?

2

synovial sheaths

protective layer around the tendon to reduce friction

what is the function of the acessory metacarpal ligaments?

stabilization of the accessory carpal bone

what is the function of the distal ligaments of the accessory carpal bone in horses?

stabilize accessory carpal bone against the pull exerted by carpal flexor muscle

what ligaments are present in the carpus of the horse?

1. collateral ligaments

2. intercarpal ligaments

antebrachiocarpal joint

most moveable joint meaning its cavity will open widest upon flexion

middle carpal joint cavity movement

very little movements

carpometacarpal cavity movements

no movements and cavity will not open at all

what is the function of the palmar carpal ligament?

to prevent overflexion of carpus joint

what is the function of the flexor retinaculum?

stabilize tendons of superficial and deep flexor muscles

what joints do you take fluid from for the carpus?

1. radiocarpal joint

2. middle carpal joint

what do we call the antebrachocarpal joint in the horse?

radiocarpal joint since horse lack ulna

what bones are involved in the fetlock joint?

1. distal end of cannon bone

2. proximal end of proximal phalanx

3. proximal sesamoid bone

what type of joint is the fetlock?

compound, synovial hinge joint

what structure will often be injured after the fetlock has been injured?

coffin joint

what side of the forelimb is the fetlock large and thick?

palmar side

where do the dorsal and palmar pouches of the fetlock project proximally between?

between the cannon bone and interosseus muscle on the palmar surface

where do the dorsal and palmar pouches of the fetlock project proximally below?

below the extensor tendons on the dorsal surface

what is pathological distension of the fetlock joint capsule known as?

1. articular windgalls

2. wind puffs

3. galls

what are the ligaments of the fetlock?

1. medial collateral ligament

2. lateral collateral ligament

3. proximal sesamoidean ligament

4. middle sesamoidian ligament

5. distal sesamoidean ligament

what makes up the proximal sesamoidean ligament?

interosseus muscle