Spine/Spinal Cord Anatomy Flashcards
What is the cona medullaris?
Termination of the spinal cord at L1/L2. It then continues down as the filum terminale and anchors to the coccyx
At birth, it terminates at L3/L4.
In the spinal cord, what is grey matter surrounded by?
White matter
Which horn is the sensory horn?
Dorsal horn
Which horn is the motor horn?
Ventral horn
What do corticospinal fibres control?
Speed, direction and agility of movements. These fibres are involved in rapid, skilled movements.
Where are the cell bodies of the corticospinal fibres?
The Primary Motor Cortex
Where do corticospinal fibres synapse?
with lower motor neurons in the ventral horn
What does the lateral corticospinal tract control?
Limb motor
What does the ventral corticopsinal tract control?
Axial motor
What does the rubrospinal tract control?
Contralateral. Proximal upper limb and trunk muscles.
- excite flexor lower motor neurons
- inhibit extensor lower motor neurons
What does the vestibulospinal tract control?
Ipsilateral. “Anti-gravity”
- excite extensor lower motor neurons
- Inhibit flexor lower motor neurons
What does the pontine (medial) reticulospinal tract control?
Axial and extensor motor neurons. Maintains posture.
What does the medullary (lateral) reticulospinal tract control?
Flexor motor neurons. Inhibits pontine reticulospinal tract. Enables modulation of stretch reflex.
What does the tectospinal tract control?
Receives information from the retina and cortical visual association areas.
Mediates reflex movements in response to visual stimuli. (can orient head & trunk towards auditory or visual stimuli)
Where does the lateral and ventral corticospinal tract decussate?
Lateral: 85-90% decussate in medullary pyramids
Ventral: 10-15% decusste at the level of exit in the spinal cord
Where does the rubrospinal tract decussate?
Ventral midbrain
Where does the vestibulospinal tract decussate?
Ipsilateral - does not decussate
Where does the reticulospinal tract decussate?
Ipsilateral - does not decussate
Where does the tectospinal tract decussate?
Ventral midbrain
