Comparative Locomotion and Clinical Assessment

Question 1

Describe the structure of the metacarpals and fetlock in the cow, sheep and pig.

Answer 1

Metacarpal 3 and 4 are fused in the cow, sheep and pig. This leaves us with a kind of double fetlock joint, with 2 sets of phalanges articulating with a single fused metapodial in the centre.

Question 2

What is the clinical relevance of the bovine limb?

Answer 2

• Lameness on dairy farms is a major cause of welfare and production issues.
• Knowledge of the normal anatomy and how this changes around calving is important to understand the pathophysiology.
• Lameness is both and individual and herd level issue.

Question 3

What are the muscle differences between the cow and horse?

Answer 3

• Less covering over the rump compared to the horse as there are no vertebral heads of the hamstrings. So can palpate more of the pelvis.
• Fibularis tertius is more muscular/fleshy than in the horse.
• Has a fibularis longus, like the dog but unlike in the horse.
• Has patellar locking system but less extreme than in the horse and do not have the capacity to full lock all the way like in the horse.

Question 4

Name and describe the 2 extensor tendons in the bovine distal limb.

Answer 4

Common/long digital extensor: lateral belly splits to both digits at PIII and medial belly goes to the medial digit at PII.

Lateral digital extensor goes to the lateral digit on PII.

Question 5

Name and describe the 2 flexor tendons of the bovine distal limb.

Answer 5

The superficial and deep digital flexor tendons will go to each functional digit, splitting at the fetlock, in the same way as other species.

Question 6

Describe the interosseous/suspensory ligament of the bovine distal limb.

Answer 6

Divides into 8 branches:

• 1 to each proximal sesamoid
• The abaxial branches send a branch abaxially to the extensor tendon
• The axial sesamoid branches send an extensor branch axially between digits to the extensor tendon

Question 7

Describe the sesamoidean ligaments of the bovine distal limb.

Answer 7

• No straight or oblique ligaments
• Cruciate sesamoidean
• Intersesamoidean
• Interdigital phalango sesamoidean (in between digits from phalanges to sesamoids)

Question 8

What is the function of the annular ligaments in the bovine distal limb?

Answer 8

Hold down flexor tendons

Question 9

What is the function of the proximal and distal interdigital ligaments of the bovine distal limb?

Answer 9

Proximal holds things in place and distal is quite superficial at the distal end of the toe, with fold of skin in between the toes underlying it. If something penetrates that, the distal interdigital ligaments is damages and leads to strain on the foot and further damage.

Question 10

What is the clinical significance of the fetlock joint capsules?

Answer 10

Fetlock joint capsules that communicate, so infections can be spread through the 2 different structures.

Question 11

How does the bovine foot compare to the equine foot?

Answer 11

• Similar to equine but has 2 cloves and is not quite as well defined.
• Less well developed lamellar dermis and interdigitation, which has implications to bovine foot health.
• Still has fatty foot pad and deep digital flexor tendon inserting on flexor process of PIII.

Question 12

What are the causes of cattle lameness?

Answer 12

Coriosis
Sole ulcers
White line disease
Sole penetration wounds
Infectious skin conditions

Question 13

What are the management methods for lameness in cattle?

Answer 13

• Clear and specialised flooring – reduced shearing forces, concussive injury, stones and debris, walking distances
• Nutrition
• Housing - reduced standing
• Regular trimming

Question 14

What is coriosis?

Answer 14

• Inflammation of the dermis and soft tissues as a result of many factors.
• Sole bruising takes a few weeks to be seen but the bruised tissue is weaker.
• Predisposes cattle to sole and toe ulcers and white line disease
• More a symptom than a disease

Question 15

How can sole ulcers form?

Answer 15

• Overlong hoof wall transfers weight caudally
• Hormones such as relaxin, can relax DDFT around calving, causing bone to push down to the ground
• Digital cushion is important as fat is mobilised post-parturition
• Pressure on sole of overlying flexor process of PIII

Ulcers can cause deeper problems in DDFT and navicular for example.

Question 16

How is healthy posture maintained in the cow?

Answer 16

• Increased flexibility of claw/hood wall and flexibility between digits reduces support for the digitigrade cow.
• Laminae are less robust
• Contribution of DDFT and common digital extensor much more crucial to maintaining healthy posture.
• PIII can shift within the claw as in horses

Question 17

Why is bovine claw trimming so important?

Answer 17

• Due to their flexibility
• Twice a year in sync with parturition
• Trim to re-shape each claw and shift weight to help the DDFT-CDE balance.
• Can add small shoes
• Check for and treat abscesses and infections

Question 18

What is white line disease/abscesses?

Answer 18

• Separation of eth unction between the sole and wall
• Shearing forces, poor paths and stone impaction
• Foreign bodies can enter
• Allows infection to enter deeper structures
• Cause abscessation

Question 19

What is ovine digital dermatitis?

Answer 19

Similar to cow in which there are 2 digits with 2 separate fetlock joints. Things can get in between digits and cause infectious issues and further issues.

Footrot and Scald

Question 20

Why may the bovine claw be amputated?

Answer 20

• Salvage surgery – other claw will be overstressed, for example, until the cow calved
• Removes source of deep infection and pain
• Need to understand the neurovascular arrangement of foot to apply local anaesthetic for surgery.

Question 21

Describe the innervation of the median nerve.

Answer 21

• Median nerve along medial aspect of palmar view
• Becomes palmar common digital nerve, that splits into a pair of nerves, abaxial and axial ones, a pair to each digit.

Question 22

Describe the innervation of the ulnar nerve.

Answer 22

• Lateral side has the ulnar nerve with a dorsal branch of the ulnar nerve heading to the distal carpus.
• Palmar branch of the ulnar nerve continues and goes on to supply lateral side of digit 4.
• On dorsal view, dorsal branch of ulnar runs alongside digit 4.

Question 23

Describe the innervation of the radial nerve.

Answer 23

More cranially, the superficial branch of the radial nerve runs along the midline of the limb, going down dorsal common digital and gives 2 branches that innervate the medial digit.

Question 24

Describe the innervation of the fibular nerves.

Answer 24

Fibular nerves, deep and superficial, supply the dorsal surface of both claws

Question 25

Describe the innervation of the tibial nerves.

Answer 25

Tibial nerve supplies plantar surfaces

Question 26

Describe the innervation of the digital nerves.

Answer 26

Once on the digits, there are nerves at each of the 4 aspects of the digits – axial and abaxial plantar and dorsal digital nerves.

Question 27

Describe the venous drainage of the bovine fore and hind feet.

Answer 27

- Palmar and plantar veins run with the flexor tendons - Dorsally there are large palpable veins in both fore and hind foot: - Fore – cephalic vein - Hind – cranial branch of the lateral saphenous

Question 28

Describe the porcine digits.

Answer 28

Porcine foot has 2 main digits and 2 accessory digits

Question 29

What do lameness workups involve?

Answer 29

Observation Signalment Presenting complaint History Clinical examination

Question 30

Describe the symmetry of gait in cursorial quadrupeds.

Answer 30

- Movements happening on the right should match those on the left. - Forelimbs bear 60% of bodyweight and hindlimbs bear 40% - Postural changes can be reduced to weightbearing on a painful limb

Question 31

How can lameness be identified by shifting weight methods?

Answer 31

- Quicker steps – reducing stance time on lame foot - Head bobbing – lifting head moves weight caudally and relieves forelimbs. Dropping head moves weight cranially and relieves hindlimbs. - Raising hips

Question 32

What anatomical aspects can be observed to identify lameness?

Answer 32

- Carpal hyperextension – palmigrade stance. Could be damage/weakened/torn to palmar fibrocartilage. - Common calcaneal tendon rupture – relatively plantigrade stance in hock joint in hindlimb. - Suspensory ligament failure – dropped fetlock appearance and digits have rotated and lifted up. Whole limb is dropping into the fetlock joint, can no long keep limb straight under gravity. If DDFT is still intact, PIII still flexes.

Question 33

Describe how lameness can be palpated.

Answer 33

- Symmetry - Swelling, heat, muscle mass or pain - Consider affected structures: joint support, such as ligaments, muscles tendons tensioned by manipulation, bone and cartilage of the joint.

Question 34

How can manipulation be used to identify lameness?

Answer 34

- Forced flexion and extension is often painful in lame joints. - Synovium is highly innervated and tension on inflamed capsule is usually painful, particularly in conditions like osteoarthritis. - Most are directed at testing integrity of ligaments and tendons. - Ligaments and tendons are situated to resist tension Manipulations to test integrity should generate movement that will put tension on the structure of interest.

Question 35

What is the advantage of using manipulation to identify lameness?

Answer 35

Imaging will not assess dynamic instability

Question 36

How can the medial glenohumeral ligament be used to identify lameness?

Answer 36

Deficiency in this ligament causes the animal to be able to abduct the limb far beyond the normal range.

Question 37

What does the Ortolani test test for?

Answer 37

Tests for sufficiency of ligaments and support structures in the normal hip joint.

Question 38

What is the outcome of the Ortolani test on a healthy animal?

Answer 38

1. Proximal pressure is put on the femur and support structures should limit movement. So a finger placed on the outer edge of the femur will not feel any movement. 2. Abduction maintains a smooth range of motion and the greater trochanter does not pop in or out.

Question 39

What is the outcome of the Ortolani test on an animal with hip joint laxity?

Answer 39

1. Proximal pressure on the femur subluxates the hip. 2. So may be possible to feel displacement of the greater trochanter if the finger is placed on the greater trochanter. 3. Adduction of the limb to replace subluxation. Palpate ‘clunk’ of femur returning to acetabulum. Can also be performed in lateral recumbency.

Question 40

What does the cranial drawer test test for?

Answer 40

Test for integrity of the cranial cruciate ligament (at the stifle)

Question 41

How is the cranial drawer test conducted?

Answer 41

1. Take hold of proximal and distal portion of the limb. 2. Displace things by translating the tibia cranially relative to the femur. 3. If this can be done, it indicates cranial cruciate ligament rupture.

Question 42

How is the tibial thrust test of the stifle conducted?

Answer 42

1. Use flexion of the hock, gastrocnemius and SDF to compress the femur against the tibia. 2. If cranial cruciate ligament in ruptured, tibial translation is allowed to occur without manipulating the stifle joint itself. 3. Cranial tibial translation is palpable as it moves.

Question 43

How is cattle lameness scored?

Answer 43

Scale of 0-3: 0 = walks with weight bearing, rhythm on all 4, flat back, long fluid strides. 1 = steps uneven or strides shortened, affecting limb/limbs and may not be immediately identifiable 2 = uneven weight bearing, immediately identifiable, obviously shortened strides, arched back possibly 3 = cannot keep up with the healthy herd, lame leg easy to identify, limping, may barely stand on lame leg/s, back arched, very lame

Question 44

How is lameness in horses measured?

Answer 44

- Often graded out of 10 - Walk, trot, straight away and back, can also do in circle on lunging Other diagnostic tools include: - Flexion tests - Nerve blocks - Radiography - Ultrasound

Question 45

What is quantitative gait assessment?

Answer 45

Generally more complex and requires specialist equipment, generally used for scientific research or referral practice. Generally used mostly in research and increasingly used in physiotherapy.

Question 46

Give some examples of quantitative methods of assessing gait and lameness.

Answer 46

- Cameras such as infrared and retro-reflective markers - Treadmills to see how an animal distributes weight and its performance - Kinetics – force plates and accelerometery - Kinematics – movements of limb/joints using cameras or motion analysis systems. Limb segment motions, speeds and angular changes assessed. - Tissue testing – tissue properties in healthy and diseased states - Bone shapes and relative muscle sizes/muscle belly architecture.

Question 47

What are the advantages of quantitative gait assessment?

Answer 47

- Can determine if weight bearing is reduced - Can follow animals over time to monitor changes and response to treatment - More accurate than subjective gait analysis

Question 48

What are the disadvantages of quantitative gait assessment?

Answer 48

- Specialist equipment and training - Expensive - Limited availability

Question 49

Which area of the cow foot bears significant weight in addition to the hoof wall?

Answer 49

Bulb. Unlike in the horse, where the bulbs are not usually in contact with the ground.

Question 50

Below the carpal joint, how many palmar sesamoid are present in a cow’s forelimb?

Answer 50

6 – 4 proximal and 2 distal

Question 51

What digit(s) do cattle, sheep and pigs bear weight on?

Answer 51

Digit III and digit IV

Question 52

What ligament prevent splaying of the 2 toes in cattle?

Answer 52

Interdigital ligaments

Question 53

In what location are sole ulcers most common in cattle?

Answer 53

Hindleg lateral claw

Question 54

Pressure on the soft tissues of the foot from what structure results in the eventual development of a sole ulcer?

Answer 54

Flexor process of PIII

Question 55

Which part of the stay apparatus works in conjunction with the patella locking mechanism to prevent hock flexion while resting muscles?

Answer 55

Superficial digital flexor

Question 56

Which nerve is required to allow a horse to lock its patella?

Answer 56

Femoral

Question 57

Which tendon, forming part of the passive stay apparatus in the forelimb, prevents flexion and ultimately collapse of the shoulder joint?

Answer 57

Internal biceps brachii tendon. It resists stretching of the biceps and so limits flexion of the shoulder by running over the intertubercular groove and intermediate tubercle and pulling on the point of origin at the supraglenoid tubercle, resisting flexion.