14. XR Vertebrae Flashcards
What type of joints are articular process joints?
Diarthroidal (synovial)
=> provide dorsal mechanical stabilisation
Describe x5 unique anatomical features of C1
- Well devloped arch
- No distinct endplates or dorsal spinous process
- Rudimentary body
- Enlarged transverse processes (wings)
- Articulate with occipital condyles (atlanto-occipital joint), and caudally with C2 (atlantoaxial joint)
Describe x5 unique features of C2
- ELongated vertebral body
- Massive spinous process
- Dens (originates from interventrum of C1, but attaches to C2 during development)
- Small trans process, 2 cranial articular processes (articulate with fovea of C1)
- Caudal endplate
Describe 4 unique features of the sacrum
- 3 fused vertebrae, broad in trans plane
- Articulate cranially with L7, caudally with Ca1 and laterally will ilial wings
- “Median sacral crest”
- Sacroiliac joint (combined synovial and cartilageneous joint)
How many caudal vertebrae are there in the dog? What are hemel arches?
- 6-23 caudal vertebrae
=> Cranially, similar to lumbar. Caudal to Ca6 -> elongated and lack vertebral arch
HEMEL ARCHES! Cd4-6: Ventral, and protect median coccygeal artery
Which 3 ligaments stabilise the Atlantoaxial joint?
- Dorsal atlantoaxial ligament
- Apical ligament of dens (inc alar branches)
- Transverse ligament of the atlas
In the dog, where is the nuchal ligament located? Function?
- Extends from spinaous process of C2 (axis) -> spinous processes of first 3 thoracic vertebrae
- Continues caudally as the supraspinous ligament
- Prevents abnormal separation of the spinous processes during flexion.
***NOT PRESENT IN CAT***
Which short ligaments join vertebrae?
- interspinous ligaments -> dorsal process to dorsal process
- Interarcuate (yellow) ligaments -> arch to arch
=> COLLECTIVELY = ligamentum flavum
List the key ligaments of the vertebral column
- AA ligaments: Apical ligament of dens (and alar branches); dorsal AA ligament; Transverse lig of atlas
- Nuchal ligament (dogs) -> Supraspinous ligament caudal to T3
- Interspinous ligaments (short)
- Interarcuate lig (short) 9YELLOW)
- Dorsal longitudinal lig (VENTRAL VERTEBRAL CANAL)
- Ventral longitudinal lig (VENTRAL TO VERTEBRAL BODIES)
- Intercapital lig (T2-T11)
-
What role do the intercapital ligs have? What is the clinical relevance?
- T2-T11 -> between rib heads
=> Reduced incidence of disc herniation T1-T11
Describe block vertebrae
- Fusion of 2+ adjacent vertebral bodies +- arches
- May predispose to adjacent disc disease due to action as fulcrum
- CERVICAL and lumbar locations
Describe hemivertebrae
- Incomplete development or ossification of part of vertebra (usually body) e.g. butterfly
- Often associated kyphosis, may lead to extradural compression
- Decreased rib spacing is a clue
- Not to be confused with compression fracture. Multiplicity, presence in brachys and well-defined margins help with this.
SEE TABLE OF KEY ANATOMICAL FEATURES OF VERT COLUMN
Describe transitional vertebrae
- Vertbrae at junctions which have charactersitics of two anatomical divisions e.g. LS, TL
NOTE: LS TRANSITIONAL -> disc degen, instability, spondylosis, nerve root compression. ASSOCIATION WITH LS DISC DISEASE AND NERVE ROOT COMPRESSION
Describe spina bifida
- Failure of development of vertebral arch +- neural tube
- With neural tube defect may see menignocoele / meningomyelocoele
- Often less severe if thoracic as rarely neural tube defect, MORE SEVERE AT LS JUNCTION
- Most common manifestationis split dorsal spinous process
***BULLDOGS AND MANX CATS**
Describe AA Subluxation
- C2 displaced dorsally relative to C1 -> extradural compression
- Congenital vs traumatic
- Congenital: Often associated with lack of dens / ligamentous structures (x3…. REMEMBER)
- Toy breeds e.g. yorkie
- Dx: Lateral rad. True lateral will hide dens (Atlas superimposed). Left 15-30 degree ventral, right dorsal to negate this
=> LOOK for fractures etc
- TWO FEATURES: Parallel dorsal laminae (MOST RELIABLE), increased distance between vert arch of atlas and spinous process of axis
List x5 abnormalities contributing to CSM
List 3 secondary changes seen with CSM
Abnormalities:
- Malformation of vert body
- Malformation of articular processes
- Malarticulation
- Instability and malalignment
- Stenosis of vert canal
2ry:
- Hypertrophy of dorsal longitudinal ligament
- Hypertrophy of ligamentum flavum
- Disc protrusion / herniation
=> Static or dynamic extradural compression.
Describe 4x typical features of Doberman CSM
- Vertebral canal stenosis (cone shaped, narrow cranially)
- Disc protrusion / extrusion
- Hypertrophy of dorsal longitudinal ligament
- Cranioventral flattening of vertebrae
-
Desribe typical features of G. Dane CSM
- Articular process malformation
- Associated Hyperostosis
=> dorsolateral compression of cord
**SYNOVIAL CYSTS also seen**
Which radiographic measurements have been described for CSM?
- Mediolateral projection -> doberman (measurements not included)
- VD projection -> distance between articular process joints : vertebral body width
What radiographic feature of compression vertebral fractures should be remembered! Which vertebrae tend to demonstrate this?
Shortening of vertebral body!
Thoracic vertbrae and L7!
What is the sens of radiography for detecting vertebral fractures? And luxations?
Fractures: 72%
Luxations: 77%
Describe the three compartment model of vertebral fractures (inc. which parts comprise each compartment)
- if 2 compartments effected -> UNSTABLE
Dorsal: Vertebral arch, articular processes, and supportive ligaments
Middle: Dorsal longitudinal ligament, dorsal annulus, dorsal portion of vertebral body
Ventral: Remainder of vertebral body, annulus fibrosus, ventral longitudinal ligament
Which 4 sites are listed as common for disc prolapse?
C2/3; C3/4; T12/13, T13/L1
