MEDIVEERSETHE PRACTICAL HUB
Identify its root on the inferior brain reference, then trace its extracranial course using the relationship map. Distinguish sensory, motor and autonomic components. Confirm its skull-base exit or spinal origin.
Zoom in, then drag to inspect. Keyboard: + / − to zoom, arrows to pan, 0 to reset. Tap the numbered markers to explore parts.
Trochlear nerve (IV): magnified reference view with a numbered learning marker. The complete original plate is available in the next view.
Image: OpenStax College / university open textbook · Source / original · CC BY 4.0Numbered markers and focused views are Mediveerse learning overlays; the original reference is linked above.
Trochlear nerve (IV)
Understand what you see.
Motor supply to superior oblique.
Zoom into the original labels. Practise pointing out each structure, then explain it aloud. Diagrams are teaching references; specimen appearance and slide staining vary.
How to recognise it.
- Identify its root on the inferior brain reference, then trace its extracranial course using the relationship map
- Distinguish sensory, motor and autonomic components
- Confirm its skull-base exit or spinal origin
Point them out.
Tap a number to open its reference, zoom in and locate the structure. Numbers stay the same across views. This key follows landmarks visible in the reference images.
Think first. Then reveal.
Say your answer aloud before opening the suggested response.
Examiner-style prompts: identify the structure, explain its relations, then answer the applied follow-up. These are revision questions, not authenticated past papers.
01Identify trochlear nerve (iv) and give its main role.+
Identify by its course and target. Distinguish sensory, motor and autonomic components. Confirm its skull-base exit or spinal origin. Motor supply to superior oblique.
02What is distinctive about its brainstem exit?+
It emerges dorsally after its fibres decussate; it is the only cranial nerve with a dorsal brainstem exit.
03When is superior oblique depression most effectively tested?+
With the eye adducted; testing isolates a movement, not every action of the muscle.
04Point out three important relations and explain their significance.+
Dorsal midbrain exit; Superior orbital fissure; Superior oblique. Motor supply to superior oblique. Use the reference plate to locate the region; the relationship map organises the associations and is not drawn to scale.
Read the references.
Credited anatomical plates, microscopy and university teaching references. Individual image credits appear below the viewer. Historical plates can use older terminology; use the lesson text for current names.