Is the inferior articular process of the facet joint anterior or posterior in the cervical spine?
What is the orientation of the zygopophyseal joints of the cervical, thoracic and lumbar spine?
What does a high riding vertebral artery refer to?
An abnormal course in C2
From what levels do the vertebral artery normally run?
In what percent of the population does the vertebral artery run in C7?
7.5% Normally runs from C1-C6
What is spinal shock?
All phenomena surrounding transaction of the spinal cord that results in temporary loss of all or most spinal reflex activity below the level of injury. Characterized by loss of bulbocavernosus reflex
What is neurogenic shock?
Hypotension and bradycardia following SCI
Which vertebrae have bifid spinous processes?
In what percent of people does the vertebral artery run in C7?
7.5% Remember - mostly it's C1-C6
Describe the safe zone for 8mm occipital screws. What are the dangers?
+/-2cm at Nuchal line +/-1cm, 1cm below the nuchal line +/-0.5cm, 2cm below the nuchal line The dangers are: Dural venous sinuses that are immediately behind these regions
Describe the insertion point for thoracic pedicle screws:
Intersection point of 2 lines: A: Vertically along: Midpoint of facet joint and/or insertion of TP into the lamina (the Valley) B: Horizontally along: Superior ridge of TP and/or inferior base of facet joint
Describe the insertion point for lumbar pedicle screws
Intersection of 2 lines: A: Vertically along the superior facet B: Horizontally along the mid-point of the TP
What level has the smallest pedicle? The largest?
Smallest overall: T4 Smallest in L-spine: L1 Largest in T-spine: T1
Define the motor level
Most caudal level with 3/5 power with 5/5 power above
What is the grading system in the ASIA scale?
E: "Excellent." No neurological compromise D: Incomplete: >50% muscles below level >/= 3/5 C: Incomplete: /= 3/5 B: Incomplete: only sensory preserved. Motor dysfunction includes sacral segments S4-5 A: "Awful". Complete. No motor or sensory function is preserved, including sacral segments S4,5
Define the sensory level
Most caudal level with normal pinprick and light touch
What is the most common incomplete cord injury?
With respect to central cord syndrome, what is the presentation, pathophysiology and prognosis?
Presentation: Motor deficit UE>LE, hands>arms Pathophysiology: Corticospinal tract, with part controlling hands centrally, are more affected Prognosis: Good. Full function rare but omst ambulatory
With respect to anterior cord syndrome, what is the presentation, pathophysiology and prognosis?
Presentation: Motor dysfunction LE>UE & dissociated sensory deficit below SCI with STT lost and dorsal columsn preserved
With respect to Brown-Sequard syndrome, what is the presentation, pathophysiology, prognosis?
Presentation: ipsilateral loss of motor function, proprioception and vibration with contralateral loss of pain and temperature Pathophysiology: Ipsilateral: Motor: LCST, Sensory: DC Contralateral: Sensory: LSTT Prognosis: Excellent 99% ambulatory
What is posterior cord syndrome?
Loss of proprioception only. Very rare
What tract is the main descending motor pathway in the cervical spinal cord?
Lateral corticospinal tract
The occiput is the thickest in what location?
5cm lateral to the external occipital protuberance
In the setting of bilateral C5-6 facet dislocation, which of the following structures is usually preserved? A: Facet joint capsules 2: Ligamentum flavum 3: Poseterior annulus 4: Anterior longitudinal ligament 5: Interspinous ligament
4: Anterior longitudinal ligament
Which of the following pedicles has the smallest transverse diameter in most people? A: T1 B: T12 C: L1 D: L3 E: S1
3: L1 Remember, T4 is the smallest overall, with L1 being the second smallest, but T4 is not listed in this question
Which area of the spinal cord has the worst collateral blood supply? The best?
Worst: T4-T9 Best: Cervical and lumbar - they have redundant supply
Describe the main blood supply to the spine? What is the name of the collateral blood supply?
Main: 1x median longitudinal anterior spinal artery 2x (right & left) longitudinal posterior spinal arteries These are supplied by various radicular arteries Collateral: Vaso Corona: anastomosis between the longitudinal vessels forming a fine pial plexus Gives limited blood supply
What artery provides the largest blood supply to the lumbar area? Where does it arise?
Artery of Adamkeiwicz. Arises most commonly from left T8-10
What is the Artery of Adamkeiwicz?
Major radicular artery supplying the longitudinal arteries in the T/L spine Usually arises from left T8-10 Can arise on right or left, anywhere from T7-L4 Usually Left T10
What are the signs of sacral dysmorphism? Why is it important and what should you do instead?
Signs: Sacralization of L5 Lumbarization of S1 Presence of mammillary processes Oval or oblong foramen Tongue in Groove sign of SI joint Important to recognize to avoid iatrogenic injury to L5 during SI screw insertion. If dysmorphic, plan for S2 screw instead (of S1)