I85PREP
⌘ K
ACVSMR study materials
ACVSMR study resources

ACVSMR practice questions

One question at a time. Build your ACVSMR understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Musculoskeletal Anatomy, Biomechanics, and Physiology

Which tissue type forms the outer layer of the menisci of the stifle joint in the dog?

  1. Hyaline cartilage
  2. Elastic cartilage
  3. Fibrocartilage Correct answer.
  4. Dense regular connective tissue

Explanation

Menisci are composed predominantly of fibrocartilage, which provides tensile strength and compressive resilience. Hyaline cartilage lines articular surfaces, while dense regular connective tissue forms tendons and ligaments.

Question 2Musculoskeletal Anatomy, Biomechanics, and Physiology

In a quadruped, which muscle group acts as the primary protractor of the forelimb during the swing phase?

  1. Digital flexors
  2. Cranial shoulder muscles Correct answer.
  3. Epaxial muscles
  4. Caudal shoulder muscles

Explanation

The cranial shoulder muscles (such as the brachiocephalicus and omotransversarius) advance the limb cranially during swing. Caudal shoulder muscles retract the limb, and epaxial muscles act on the vertebral column.

Question 3Musculoskeletal Anatomy, Biomechanics, and Physiology

The patellar reflex in the dog tests the integrity of which nerve and spinal cord segments?

  1. Tibial nerve, S1-S3
  2. Sciatic nerve, L6-S1
  3. Femoral nerve, L4-L6 Correct answer.
  4. Obturator nerve, L4-L5

Explanation

The patellar reflex is mediated by the femoral nerve with afferent and efferent limbs through spinal segments L4-L6. The reflex arc involves the quadriceps femoris muscle group.

Question 4Musculoskeletal Anatomy, Biomechanics, and Physiology

Which bone of the canine forelimb articulates with the radius and ulna to form the elbow joint?

  1. Carpus
  2. Scapula
  3. Humerus Correct answer.
  4. Metacarpus

Explanation

The elbow joint is formed by the articulation of the distal humerus with the proximal radius and ulna. The scapula articulates with the humerus at the shoulder joint.

Question 5Musculoskeletal Anatomy, Biomechanics, and Physiology

In the horse, which structure forms the functional stay apparatus that locks the stifle and hock during standing?

  1. The patellar locking mechanism with the medial patellar ligament Correct answer.
  2. The reciprocal apparatus alone
  3. The deep digital flexor tendon only
  4. The suspensory ligament alone

Explanation

The horse's passive stay apparatus relies in part on the medial patellar ligament engaging the distal femoral trochlea, locking the stifle in extension. This coupling with the reciprocal apparatus locks the hock as well.

Question 6Musculoskeletal Anatomy, Biomechanics, and Physiology

Which collagen type predominates in the superficial zone of articular cartilage?

  1. Type I
  2. Type IV
  3. Type III
  4. Type II Correct answer.

Explanation

Articular cartilage is predominantly composed of type II collagen, which forms a network that resists tensile forces. Type I is found in fibrocartilage and bone, while types III and IV are not the main cartilage collagens.

Question 7Musculoskeletal Anatomy, Biomechanics, and Physiology

Which muscle is the primary flexor of the elbow in the dog?

  1. Brachialis Correct answer.
  2. Teres major
  3. Triceps brachii
  4. Biceps brachii

Explanation

The brachialis is the principal flexor of the elbow joint in the dog. The biceps brachii also flexes the elbow but is primarily a shoulder flexor, and the triceps is the main extensor.

Question 8Musculoskeletal Anatomy, Biomechanics, and Physiology

The nuchal ligament in the horse is composed primarily of which tissue?

  1. Hyaline cartilage
  2. Fibrocartilage
  3. Reticular connective tissue
  4. Elastic connective tissue Correct answer.

Explanation

The nuchal ligament is a highly elastic structure that passively supports the head and neck. Its high elastin content allows it to store and return energy during locomotion.

Question 9Musculoskeletal Anatomy, Biomechanics, and Physiology

During the stance phase of a trotting dog, the ground reaction force vector in the forelimb is directed primarily in which manner relative to the limb?

  1. Purely vertical with no horizontal component
  2. Directed dorsally away from the limb
  3. Craniocaudal with a vertical component Correct answer.
  4. Purely horizontal with no vertical component

Explanation

Ground reaction forces during stance have both a vertical component supporting body weight and a craniocaudal component related to braking and propulsion. The vector is not purely vertical or horizontal.

Question 10Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following best describes the role of the reciprocal apparatus in the horse's hindlimb?

  1. It locks the forelimb fetlock during weight bearing
  2. It controls digital extension during the swing phase
  3. It provides lateral stability to the carpus
  4. It couples stifle and hock motion through the peroneus tertius and superficial digital flexor Correct answer.

Explanation

The reciprocal apparatus mechanically links the stifle and hock via the peroneus tertius and superficial digital flexor, so flexion of one joint produces predictable motion at the other. This coupling is central to equine hindlimb biomechanics.

Question 11Musculoskeletal Anatomy, Biomechanics, and Physiology

A dog presents with a cranial cruciate ligament rupture. Which biomechanical consequence is most directly expected at the stifle?

  1. Increased medial patellar luxation
  2. Decreased joint effusion
  3. Increased hock extension
  4. Increased cranial tibial translation Correct answer.

Explanation

The cranial cruciate ligament restrains cranial tibial translation relative to the femur. Its rupture allows the tibia to translate cranially, producing the cranial drawer sign.

Question 12Musculoskeletal Anatomy, Biomechanics, and Physiology

Which structure primarily resists varus and valgus forces at the canine elbow?

  1. The olecranon bursa
  2. The collateral ligaments Correct answer.
  3. The annular ligament
  4. The anconeal process

Explanation

The medial and lateral collateral ligaments resist valgus and varus angulation respectively at the elbow. The annular ligament stabilizes the radial head in pronation and supination.

Question 13Musculoskeletal Anatomy, Biomechanics, and Physiology

Which muscle group provides the primary propulsive force during the push-off phase of the canine gallop?

  1. Neck extensors
  2. Hip extensors and stifle extensors Correct answer.
  3. Digital flexors
  4. Hip flexors

Explanation

Push-off requires powerful extension of the hip and stifle, driven by the gluteal and quadriceps muscle groups. Hip flexors dominate the swing phase rather than push-off.

Question 14Musculoskeletal Anatomy, Biomechanics, and Physiology

In the horse, the suspensory ligament (third interosseous muscle) primarily functions to do which of the following?

  1. Prevent hyperextension of the fetlock Correct answer.
  2. Flex the carpus during swing
  3. Extend the elbow
  4. Adduct the forelimb

Explanation

The suspensory ligament supports the fetlock and prevents hyperextension during weight bearing. It acts as a key component of the passive stay apparatus of the forelimb.

Question 15Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following describes the normal orientation of the canine scapula relative to the body wall?

  1. It is oriented perpendicular to the ground
  2. It lies horizontally across the thorax
  3. It is oriented cranioventrally at an angle to the horizontal Correct answer.
  4. It lies roughly parallel to the vertebral column

Explanation

The canine scapula slopes cranioventrally, allowing the shoulder joint to sit lower and more cranial than the dorsal scapular border. This orientation influences forelimb protraction and stride mechanics.

Question 16Musculoskeletal Anatomy, Biomechanics, and Physiology

Which factor most increases the risk of injury to the equine superficial digital flexor tendon during high-speed exercise?

  1. High peak tendon strain near maximal exercise Correct answer.
  2. Low ambient temperature during exercise
  3. Reduced hoof wall thickness
  4. Increased joint effusion

Explanation

The superficial digital flexor tendon experiences high peak strains during fast work, which can exceed its elastic limit and lead to cumulative microdamage. This strain-based mechanism underlies overuse injury.

Question 17Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following best explains why the equine digit functions as an energy-storing structure during locomotion?

  1. Rigid articulation of the distal interphalangeal joint
  2. Elastic recoil of the suspensory apparatus and flexor tendons Correct answer.
  3. Calcification of the collateral cartilages
  4. Active contraction of the digital extensors

Explanation

The suspensory apparatus and flexor tendons stretch during stance and recoil elastically, storing and returning energy. This reduces the metabolic cost of locomotion at speed.

Question 18Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following muscles is a major extensor of the hip in the dog?

  1. Sartorius
  2. Iliopsoas
  3. Gluteus medius Correct answer.
  4. Pectineus

Explanation

The gluteus medius is a powerful hip extensor and a key propulsive muscle. The iliopsoas is primarily a hip flexor.

Question 19Musculoskeletal Anatomy, Biomechanics, and Physiology

Which structure transmits force from the quadriceps muscle to the tibia?

  1. The patellar ligament Correct answer.
  2. The meniscofemoral ligament
  3. The collateral ligaments
  4. The cranial cruciate ligament

Explanation

The patellar ligament is the continuation of the quadriceps tendon and inserts on the tibial tuberosity, transmitting extensor force. The cruciate and collateral ligaments stabilize rather than transmit extensor force.

Question 20Musculoskeletal Anatomy, Biomechanics, and Physiology

In a horse with a flexural deformity of the distal interphalangeal joint, which structure is most directly responsible for the abnormal flexion?

  1. The deep digital flexor tendon Correct answer.
  2. The common digital extensor tendon
  3. The suspensory ligament
  4. The collateral ligaments of the coffin joint

Explanation

Flexural deformity reflects disproportionate tension in the deep digital flexor tendon, which flexes the distal interphalangeal joint. The extensor tendon opposes this action.

Question 21Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following best describes the biomechanical function of the menisci during weight bearing?

  1. They produce synovial fluid
  2. They generate active joint motion
  3. They anchor the cruciate ligaments
  4. They convert point loads into distributed loads across the tibial plateau Correct answer.

Explanation

Menisci increase joint congruence and distribute compressive loads over a larger contact area, reducing peak stress on articular cartilage. They are passive structures and do not generate motion.

Question 22Musculoskeletal Anatomy, Biomechanics, and Physiology

During a walk, the canine forelimb and hindlimb on the same side are approximately how far out of phase?

  1. 180 degrees Correct answer.
  2. 90 degrees
  3. 0 degrees
  4. 270 degrees

Explanation

In the walk, the ipsilateral forelimb and hindlimb are roughly half a cycle out of phase, which corresponds to about 180 degrees. This alternating pattern contributes to the four-beat rhythm of the walk.

Question 23Musculoskeletal Anatomy, Biomechanics, and Physiology

Which property of articular cartilage allows it to withstand compressive loads by redistributing interstitial fluid pressure?

  1. Pure elastic behavior
  2. Plastic deformation
  3. Viscoelastic creep only
  4. Biphasic poroelastic behavior Correct answer.

Explanation

Articular cartilage behaves as a biphasic material in which fluid pressurization within the matrix supports much of the compressive load. This poroelastic response is time-dependent and central to load carriage.

Question 24Musculoskeletal Anatomy, Biomechanics, and Physiology

In the horse, the passive stay apparatus of the forelimb depends on which combination of structures to resist flexion of the shoulder and elbow during standing?

  1. The reciprocal apparatus and the patellar ligaments
  2. The suspensory ligament and the deep digital flexor tendon
  3. The lacertus fibrosus and the collateral ligaments of the elbow Correct answer.
  4. The nuchal ligament and the supraspinous ligament

Explanation

The lacertus fibrosus transmits tension from the biceps to the extensor carpi radialis, and the elbow collateral ligaments resist flexion, together supporting the forelimb passively. This arrangement minimizes muscular effort during standing.

Question 25Musculoskeletal Anatomy, Biomechanics, and Physiology

Which factor most directly determines the magnitude of peak vertical force measured at the hoof during a trot?

  1. Coat color
  2. Body mass and speed of locomotion Correct answer.
  3. Hoof wall pigmentation
  4. Resting heart rate

Explanation

Peak vertical ground reaction force scales with body mass and increases with speed because of greater inertial and accelerative demands. Other listed factors do not meaningfully affect force magnitude.

Question 26Musculoskeletal Anatomy, Biomechanics, and Physiology

Which type of muscle fiber is characterized by a high oxidative capacity and resistance to fatigue?

  1. Type IIa
  2. Type I Correct answer.
  3. Type IIb
  4. Type IIx

Explanation

Type I fibers are slow-twitch, have a high mitochondrial density and oxidative enzyme activity, and are fatigue-resistant, making them suited for posture and endurance.

Question 27Musculoskeletal Anatomy, Biomechanics, and Physiology

In the canine forelimb, which bone articulates with the distal end of the radius to form the antebrachiocarpal joint?

  1. Accessory carpal bone
  2. Radial carpal bone Correct answer.
  3. Ulnar carpal bone
  4. Second carpal bone

Explanation

The antebrachiocarpal joint is formed by the distal radius and the proximal row of carpal bones, with the radial carpal bone being the primary articulation.

Question 28Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following best describes the primary function of the equine suspensory ligament (third interosseous muscle) during locomotion?

  1. To extend the carpus
  2. To support the fetlock and prevent hyperextension Correct answer.
  3. To adduct the forelimb
  4. To flex the distal interphalangeal joint

Explanation

The suspensory ligament runs from the proximal metacarpus to the proximal sesamoids and extensor branches, acting as a sling to support the fetlock and limit hyperextension during weight bearing.

Question 29Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following is a key biomechanical function of the menisci in the stifle joint?

  1. To produce synovial fluid
  2. To limit flexion of the stifle
  3. To transmit muscle force to the tibia
  4. To increase congruence between the femoral condyles and tibial plateau Correct answer.

Explanation

The menisci are wedge-shaped fibrocartilages that deepen the tibial plateau and improve congruence, thereby distributing load and reducing contact stress.

Question 30Musculoskeletal Anatomy, Biomechanics, and Physiology

During a trot, the canine forelimb and ipsilateral hindlimb are approximately how far out of phase?

  1. 90 degrees
  2. 0 degrees
  3. 180 degrees Correct answer.
  4. 270 degrees

Explanation

At a trot, the forelimb and ipsilateral hindlimb move in opposite phases, approximately 180 degrees out of phase, creating a diagonal couplet support pattern.

Question 31Musculoskeletal Anatomy, Biomechanics, and Physiology

In the horse, the passive stay apparatus of the forelimb relies on which combination of structures to resist flexion of the carpus and fetlock?

  1. Collateral ligaments of the carpus and suspensory ligament
  2. Extensor carpi radialis and common digital extensor
  3. Lacertus fibrosus and flexor carpi radialis Correct answer.
  4. Accessory ligament of the superficial digital flexor and check ligament of the deep digital flexor

Explanation

The lacertus fibrosus (biceps brachii tendon) and the radial carpal extensor tendon help stabilize the carpus, while the suspensory ligament supports the fetlock, together forming key components of the passive stay apparatus.

Question 32Musculoskeletal Anatomy, Biomechanics, and Physiology

Which muscle is a major extensor of the hip in the dog?

  1. Iliopsoas
  2. Biceps femoris Correct answer.
  3. Gracilis
  4. Rectus femoris

Explanation

The biceps femoris is a large caudolateral muscle of the thigh that extends the hip and stifle, and flexes the hock.

Question 33Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following structures transmits force from the quadriceps muscle to the tibia?

  1. Cranial cruciate ligament
  2. Patellar tendon Correct answer.
  3. Fabella
  4. Popliteal ligament

Explanation

The patellar tendon (ligament) connects the patella to the tibial tuberosity and transmits the force of the quadriceps muscle to extend the stifle.

Question 34Musculoskeletal Anatomy, Biomechanics, and Physiology

Which of the following best explains why the equine superficial digital flexor tendon is prone to injury during high-speed exercise?

  1. It receives a poor blood supply.
  2. It is primarily composed of type I collagen.
  3. It stores and releases large amounts of elastic energy. Correct answer.
  4. It has a high elastic modulus and low failure strain.

Explanation

The superficial digital flexor tendon functions as an elastic energy store during high-speed exercise, subjecting it to high strains that can exceed its capacity and lead to injury.

Question 35Musculoskeletal Anatomy, Biomechanics, and Physiology

In the dog, the tendon of which muscle passes through the supratrochlear foramen of the humerus?

  1. Triceps brachii
  2. Coracobrachialis
  3. Brachialis Correct answer.
  4. Biceps brachii

Explanation

The supratrochlear foramen is an opening in the distal humerus between the olecranon fossa and the radial fossa, and the tendon of the brachialis muscle passes through it as it courses to insert on the proximal ulna. The biceps and triceps do not traverse this foramen.

Question 36Musculoskeletal Anatomy, Biomechanics, and Physiology

Which statement best describes the arrangement of the equine stay apparatus in the hindlimb that allows the stifle and hock to lock together?

  1. The gastrocnemius tendon alone locks the hock while the stifle remains free to flex independently
  2. The patellar ligaments and the medial patellar fibrocartilage engage the trochlear ridges so that stifle extension is coupled to hock extension via the reciprocal apparatus Correct answer.
  3. The cruciate ligaments lock the femorotibial joint, and the collateral ligaments independently lock the tarsus
  4. The peroneus tertius acts as the sole mechanism coupling the stifle and hock, with the superficial digital flexor playing no role

Explanation

In the horse, the medial patellar ligament and parapatellar fibrocartilage can hook over the medial trochlear ridge, holding the stifle in extension. Through the reciprocal apparatus (peroneus tertius cranially and superficial digital flexor caudally), stifle extension is mechanically linked to hock extension, allowing standing rest.

Question 37Musculoskeletal Anatomy, Biomechanics, and Physiology

Which muscle of the canine pelvic limb is the primary flexor of the stifle joint?

  1. Semimembranosus
  2. Quadriceps femoris
  3. Popliteus Correct answer.
  4. Biceps femoris

Explanation

The popliteus muscle arises from the lateral femoral condyle and inserts on the caudal tibia, acting primarily to flex the stifle and to rotate the tibia. The quadriceps is the main extensor, while the hamstring muscles act mainly at the hip and hock.

Question 38Musculoskeletal Anatomy, Biomechanics, and Physiology

A dog bears weight on a limb in which the femoral head is displaced dorsally out of the acetabulum. Which biomechanical consequence is most directly expected at that coxofemoral joint?

  1. Increased congruency between the femoral head and acetabulum
  2. Loss of the normal concavo-convex load transfer and concentration of force on the dorsal acetabular rim Correct answer.
  3. Increased joint contact area with reduced articular cartilage stress
  4. Enhanced stability from the round ligament under tension

Explanation

The coxofemoral joint normally transfers load through a congruent ball-and-socket interface with the round ligament and joint capsule providing stability. When the femoral head is displaced dorsally, congruency is lost and load is concentrated on the dorsal acetabular rim, predisposing to further damage.

Question 39Musculoskeletal Anatomy, Biomechanics, and Physiology

Which property of skeletal muscle allows it to increase force output as it is stretched from its resting length up to an optimal length?

  1. The force-velocity relationship at high shortening velocities
  2. The length-tension relationship determined by actin-myosin overlap Correct answer.
  3. The series elastic recoil of the tendon alone
  4. The passive tension generated by the sarcoplasmic reticulum

Explanation

Force generation depends on the degree of overlap between actin and myosin filaments; force rises as overlap increases toward an optimal sarcomere length and falls when the muscle is overstretched or overly shortened. This is the basis of the length-tension relationship.

Question 40Musculoskeletal Anatomy, Biomechanics, and Physiology

In the equine forelimb, which structure forms the principal check against hyperextension of the carpus during weight bearing?

  1. The extensor carpi radialis tendon
  2. The collateral ligaments of the carpus
  3. The palmar carpal ligament Correct answer.
  4. The accessory ligament of the superficial digital flexor

Explanation

The palmar carpal ligament lies on the palmar aspect of the carpus and, with the joint capsule, resists hyperextension of the carpal joints during weight bearing. The collateral ligaments primarily resist varus/valgus and rotational forces rather than hyperextension.

Question 41Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

Which imaging modality is generally considered the reference standard for detecting acute full-thickness injury of the cranial cruciate ligament in a dog?

  1. Ultrasonography
  2. Radiography
  3. Magnetic resonance imaging Correct answer.
  4. Computed tomography

Explanation

MRI provides direct multiplanar visualization of the cruciate ligaments and surrounding soft tissues, so it is the reference standard for ligament injury. Radiography and CT show only secondary or indirect signs, and ultrasound is limited by the enclosed anatomy of the stifle.

Question 42Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

On a lateral radiograph of the canine stifle, which finding best supports the presence of joint effusion?

  1. Loss of the infrapatellar fat pad radiolucency Correct answer.
  2. Increased density of the patella
  3. Widening of the tibial plateau angle
  4. Narrowing of the femorotibial joint space

Explanation

Joint fluid displaces and opacifies the infrapatellar fat pad, reducing its normal radiolucency on a lateral view. Joint-space narrowing and plateau angle reflect cartilage loss and conformation rather than effusion.

Question 43Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

A dog is examined 24 hours after acute hindlimb lameness. Which diagnostic test is most appropriate for confirming a suspected cranial cruciate ligament rupture at this stage?

  1. Orthopedic examination including cranial drawer and tibial thrust Correct answer.
  2. Nuclear scintigraphy of the lumbar spine
  3. Computed tomography of the pelvis
  4. Serum C-reactive protein measurement

Explanation

Manual orthopedic tests such as the cranial drawer and tibial compression tests directly assess ligament integrity and are the first-line diagnostic for acute rupture. Advanced imaging is reserved for equivocal cases or surgical planning.

Question 44Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

Which ultrasound finding is most consistent with a complete rupture of the Achilles tendon in a dog?

  1. Increased echogenicity of the calcaneus
  2. Diffuse mild thickening with preserved linear fiber pattern
  3. Discontinuity of the tendon fibers with a gap and surrounding hypoechoic hemorrhage Correct answer.
  4. Anechoic fluid within the tendon sheath only

Explanation

Complete rupture appears as a clear disruption of the normal linear fibrillar pattern with a gap and hematoma. Preserved fibers with mild thickening suggests tendinopathy rather than rupture.

Question 45Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

Which radiographic view is most useful for evaluating the femoral trochlear groove and patellar alignment in a dog with suspected medial patellar luxation?

  1. Craniocaudal (caudocranial) view
  2. Skyline (tangential) view Correct answer.
  3. Flexed lateral view
  4. Lateral view

Explanation

The skyline view images the patella within the trochlear groove tangentially, allowing assessment of groove depth and patellar tracking. Standard lateral and craniocaudal views do not isolate the groove.

Question 46Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

During a lameness examination, a dog shows a consistent head nod downward when the right forelimb contacts the ground. Which limb is affected?

  1. Right hindlimb
  2. Left hindlimb
  3. Right forelimb Correct answer.
  4. Left forelimb

Explanation

A head nod that drops toward the side of the lame limb during that limb's stance indicates the lame forelimb. The head rises when the sound limb bears weight.

Question 47Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

Which of the following is the primary advantage of digital radiography over screen-film radiography in equine sports medicine?

  1. Higher spatial resolution than film
  2. Ability to image soft tissue in detail
  3. Post-processing and immediate image review Correct answer.
  4. Elimination of the need for radiation safety

Explanation

Digital systems allow immediate review and post-processing such as windowing and edge enhancement, which aids subtle lesion detection. Film retains an edge in spatial resolution, and radiation safety is still required.

Question 48Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

A gait analysis shows a horse with a shortened cranial phase of the stride in one forelimb. Which finding does this most directly indicate?

  1. Increased weight-bearing on that limb
  2. Neurologic deficits in the contralateral limb
  3. Pain or reduced protraction of that limb Correct answer.
  4. Sole bruising of the contralateral hoof

Explanation

A shortened cranial phase reflects reduced protraction, typically because of pain in that limb. It is a kinematic indicator of lameness rather than a sign of increased loading.

Question 49Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

A dog has a chronic, slowly progressive hindlimb lameness with muscle atrophy and pain on hip extension. Which imaging test is most appropriate as the initial diagnostic for suspected hip dysplasia?

  1. Ultrasonography of the coxofemoral joint
  2. Magnetic resonance imaging of the pelvis
  3. Computed tomography with contrast
  4. Ventrodorsal extended-hip radiograph Correct answer.

Explanation

The ventrodorsal extended-hip radiograph is the standard screening and initial diagnostic test for hip dysplasia, allowing assessment of congruence and secondary changes. Advanced imaging is reserved for surgical planning or equivocal cases.

Question 50Sports Medicine and Rehabilitation Diagnosis and Diagnostic Imaging

In a horse with suspected navicular disease, which radiographic changes are most characteristic on a palmaroproximal-palmarodistal (upright pedal) view?

  1. Enlargement of the navicular bone and increased number of synovial invaginations Correct answer.
  2. Osteophyte formation on the dorsal distal phalanx
  3. Widening of the distal interphalangeal joint space
  4. Fracture of the distal phalanx

Explanation

Navicular disease is characterized by enlarged synovial invaginations (lollipop lesions), sclerosis, and altered shape of the navicular bone on the upright pedal view. The other findings relate to different structures.