434 Canine Sports Medicine and Rehabilitation
not been incorporated into specific require
ments for canine athletes. These studies have,
however, dramatically illuminated the differ
ences in breeds and among individual dogs
within breeds.
The sum of these studies clearly demon
strates that specifics about spinal conformation
can be measured, and through genetics, specific
training, and attention to detailed anatomy, bet
ter functioning spines are possible.
Congenital predispositions
Malformations
Spinal anomalies are usually considered inci
dental findings. Additional ribs and absence of
ribs, as well as additional lumbar vertebrae, are
probably the most common vertebral anoma
lies. Occasionally a lack of a transverse spine is
noted and on occasion the anticlinal vertebra is
not T11 but one of the neighboring vertebrae.
Spina bifida
Spina bifida is an uncommon malformation of
the spine that is frequently an incidental find
ing. Spina bifida is an interruption of or incom
plete fusion of the dorsal spinal arches. This can
occur at several vertebral sites but is most often
recognized at the level of the sacrum and some
times involves L7. Spina bifida is most common
in the screw‐tailed breeds: Boston Terriers,
French Bulldogs, English Bulldogs, and others.
This malformation is sometimes associated
with incomplete formation of the neural tube
causing dysplasia of the spinal cord and protru
sions of the meninges and occasionally also the
spinal cord. Dogs in which the sacral segments
of the spinal cord are malformed are often
presented for a lack of urinary and/or fecal
control.
Caudal occipital malformation syndrome
Caudal occipital malformation syndrome has
been described (Churcher & Child, 2000;
Rusbridge et al., 2000; Rusbridge & Knowler,
2003). In this condition there is crowding of the
cerebellum within the caudal fossa of the skull.
This malformation often leads to a fluid‐filled
tubular structure, a syrinx, forming within the
cervical spinal cord and in many cases
hydrocephalus (Figure 17.12). Flow dynamics
and the Venturi effect are suspected to be
responsible for the syrinx formation. These
fluid‐filled tubes can occur when the dogs are
very young or can develop as the dog ages.
Affected dogs often present with neck pain and
tetraparesis, frequently affecting the thoracic
limbs to a greater extent than the pelvic limbs.
A peculiar obsessive scratching of the neck area
is a common occurrence. This disease is more
prevalent in certain toy breeds such as the
Cavalier King Charles Spaniel and Brussels
Griffon, although it has also been described in
other breeds.Atlanto‐axial instability
The second cervical vertebra, C2, is held in
place by several ligamentous structures. The
bony projection, the odontoid process or dens,
of C2 attaches to the ventral floor of C1 and
allows for rotation of the head within limits in
each direction. Dogs who have atlanto‐axial
subluxations usually have a hypoplastic dens
or aplasia of the dens. This condition occurs
most commonly in toy and miniature breeds,Figure 17.12 Lateral MRI of a Cavalier King Charles
Spaniel with caudal occipital malformation syndrome
(COMS). Note the syrinx in the center of the spinal cord
(arrow). The white color denotes fluid as this is a
T2 image.