Axial Skeleton Flashcards
How many cervical vertebrae does a horse have?
7
Which cervical vertebrae have no specific identifiable features?
3rd, 4th and 5th
What is the name given to C1?
Atlas
What is the name given to C2?
Axis
Describe the features of C1
Develops in two lateral halves which gradually ossify
Describe the features of C2
- Separate centres of ossification for the dens, head, body and caudal epiphysis.
- The dens fuses with the head at approx 7 months
Compare the difference in size between C5, C6 and C7
C6 is shorter than C5
C7 is shorter than C6
Which cervical vertebrae may have a small dorsal spinous process which may be fairly prominant?
C7
How is T1 recognised?
Large dorsal spinous process
What are the presenting clinical signs of neck pain
- Neck stiffness/pain/ ”locking”
- Acute trauma
- Poor performance/ problems performing specific manoeuvres
- Ataxia (usually low grade but can be severe)
How can the neck be examined?
- Visualisation: position, head carriage, position of limbs/gait
- Palpation: symmetry, atrophy, pain, fasciculations/spasm
- Range of motion: lateral, dorso-ventral flexion
- Neurological exam
- Dynamic exam: walking, trot, lunge, ridden
Which 4 issues to be ruled out when examining the neck?
- Lameness
- Back problems
- Tack issues
- Dentistry
Name 3 common conditions of the neck
Developmental - Cervical Vertebral Malformation
Degenerative - Osteoarthritis
Trauma - fractures
Name 3 rare conditions of the neck
Neoplasia
Congenital malformations
Infectious
‘Wobblers’ is a name given to which condition?
Cervical vertebral malformation
Which horses are predisposed to CVM?
Warmbloods, thoroughbreds
How does CVM appear on radiography
Varying spectrums of malformation of bones
- Narrowed spinal canal
- Luxations between vertebrae
- Arthritis
Describe the features of cervical osteoarthritis
- Aetiology: age, CVM, previous trauma
- Cartilage erosion and subchondral bone sclerosis
- Periarticular osteophytosis
- Synovial cysts/soft tissue hypertrophy
How is cervical OA treated?
- NSAIDs
- IA medications: corticosteroids, hyaluranon
- Physiotherapy
- Exercise
- Often palliative Tx only
What are the 3 negative prognostic indicators for cervical OA?
Severity of signs/radiographs
Young horse
Ataxia
How do cervical fractures occur?
NH racehorses, event horses, point to point more at risk
Field injury/freak accident also possible
- Kicks from other horses
- Car accidents
- Horse running into objects because of fright
What is the prognosis of a cervical fracture?
- Dependant on location, configuration, open vs closed, single or polyostotic
- Many are not treatable
- Conservative treatment is often only realistic chance
- Surgical repair – isolated reports in literature
How many thoracic vertebrae are there in the horse?
18
13 in dog and cat
How many lumbar vertebrae does a horse have?
6
7 in dog
Which thoracic vertebrae is most identifiable? Why?
T15 - vertically inclined, the ones proximal of this are sloped caudally and the distal ones are sloped cranially
What are the presenting signs of thoracolumbar spine conditions?
- Poor performance
- Behavioural changes
- Uncomfortable when ridden/ “doesn’t feel right”
- Stiffness in the back
- Back spasms
- Difficulty in being tacked up
- Bucking/rearing
How would diseases of the thoracolumbar spine present on physical exam?
- Specific to the back
- Obvious swellings: fractured withers/acute supraspinous desmitis/muscle haematoma/poor fitting saddle
- Presence of white hairs: may represent poor saddle fit, esp behind withers
How would diseases of the thoracolumbar spine present on palpation?
Abnormal reactions include:
- Ears back/teeth grinding/biting/kicking/tail swishing
- Muscle fasciculations
- Guarding or splinting of back in anticipation
- Bucking/rearing
How can you flex a horses back?
Use blunt object
Cranial to caudal then lateral
- Thoracolumbar extension then thoracolumbar flexion
- Lateral excursion away from stimulus (lateroflexion)
- Note breed differences (TB versus Cob)
Which part of a dynamic exam is most useful for back examination?
Lunge
- Muscle fasciculations/spasms/guarding/splinting
- Breaking into canter
- Head held forward/neck extended
- Lack of hindlimb impulsion
How does fractures of the withers occur?
Trauma - falling over backwards
How is fracture of the withers managed?
Rest = 2-3months box rest
NSAIDs
Fibrous union
Long-term outcome fair/good
How is saddle induced trauma treated?
Rest/ice
Ultrasound therapy
Low-powered laser for indolent wounds
Correct inciting cause
Which ligament can be damaged in the back?
Supraspinous
What are the clinical signs of supraspinous ligament damage?
- Rigid gait/head elevated/reduced stride
- Heat/pain/swelling (acute)
- Thickening (chronic)
How is supraspinous ligament damage diagnosed?
US
How is supraspinous ligament damage treated? acute vs chronic?
Acute: Cold compress/NSAIDs/Rest
Chronic: Physiotherapy (e.g. therapeutic ultrasound; Equissage; stretching/belly lifts); showckwave (?)
How is impingement of the dorsal spinous processes diagnosed?
Common finding!
Probable conformational as well as degenerative underlying aetiology
Radiography:
- Confirm significance
- Intra-lesional LA
- Exclude other causes of pain first
How is impingement of the dorsal spinous processes treated?
- Medical/Conservative
e.g. PBZ, shockwave therapy, physiotherapy
e.g. removal of dorsal spinous processe - Surgical = Remove all or part of the affected DSP’s
Describe the anatomical features of the lumbar spine
- Wide transverse processes and wide dorsal spinous processes
- A lot of fat and muscle in the area can make it hard to radiograph
- 6 vertebrae
