Cervical vertebral column Flashcards
(140 cards)
Why is it common for more pronounced motor dysfunction to be evident in the pelvic limbs rather than thoracic with a cervical spinal cord lesion?
The descending UMN tracts to the pelvic limbs are more peripherally located.
What is central spinal cord syndrome?
When motor function is more severely affected in the thoracic rather than the pelvic limbs due to a lesion affecting the central aspect of the spinal cord
Are reduced thoracic limb withdrawal reflexes with normal mentation definitive for localization to C6-T2?
No, decreased withdrawal reflexes can sometimes occur with C1-C5 lesions
Can a lesion affecting the C6-T2 spinal cord segments cause an absent cutaneous trunci?
Yes, if the lesion affects the C8-T2 spinal cord segments.
How fast does neurogenic atrophy occur compared to disuse?
7 days for neurogenic, disuse likely to take weeks and is less pronounced
Where do the motor neurons of the phrenic nerve originate?
C5-C7 (C7-C5 keeps the diaphragm alive).
Absent nociception is uncommon in dogs with cervical lesions as it would likely also occur with complete respiratory failure.
Describe the cutaneous dermatomes of the thoracic limb
What is nerve root signature?
Holding of the thoracic limb in a partially flexed position, consistent with lesions affecting the C6-T2 spinal nerve roots
Lesions in what part of the cervical spinal cord are most likely to cause Horner’s syndrome?
T1-T3.
Is incontinence common with cervical spinal cord lesions?
No, more common with lesions caudal to T2.
List some diseases that might affect the C1-C5 spinal cord segments.
List some diseases that might affect the C6-T2 spinal cord segments.
Outline a diagnostic approach to cervical spinal cord disease.
What are two potential ventral approaches to the cervical spinal cord?
1) Midline approach.
2) Paramedian approach (separation of the right sternohyoideus and right sternocephalicus muscles. Helps to protect the trachea, right recurrent laryngeal nerve, and right carotid sheath).
What are two potential surgical approaches to the atlantoaxial articulation?
1) Ventral.
2) Parasagittal: dissection between the right sternothyroideus and sternocephalicus muscles. Improves exposure of the joint, and avoids dissection around the thyroid gland, trachea and recurrent laryngeal nerves.
What is the name of the ventral prominence on the caudal aspect of C1?
Ventral tubercle, can be used to locate the C1-C2 joint space
What are the two causes of AA instability?
Ligamentous or osseous abnormalities.
What are primary motions of the atlanto-occipital and atlantoaxial joints)
Atlanto-occipital: flexion and extension (yes joint).
Atlantoaxial: rotational (no joint).
The first spinal nerve pass out of which foramen?
The lateral vertebral foramen of the atlas.
The vertebral artery also passes through the lateral vertebral foramen after passing through the transverse foramen (in the wings of the atlas).
Name the ligamentous attachments to the dens
Transverse ligament of the atlas: holds the dens in the ventral aspect of the vertebral foramen
Apical ligament: attaches dens to basiocciptal bone
Alar ligaments: attaches dens to occipital processes. Most important for ventrodorsal shearing forces
What abnormalities may result in AA instability?
Atlantoaxial joint hypoplasia or aplasia (46% of dogs), dysplasia (34%), dorsal angulation, absence of transverse ligament and separation of dens.
Trauma can also cause tearing of the ligaments or fracture of the dens.
What proportion of dogs with AA instability have a normal dens?
24%
What is the most common clinical sign associated with AA luxation?
Neck pain.
How common are gait dysfunctions in dogs with AA subluxation?
In up to 94% of dogs