Phase 2: Applied Clinical Radiology and Anatomical Reasoning
From anatomy to diagnosis
Phase 2 asks you to convert anatomical knowledge into a radiological conclusion. The examiner is testing pattern recognition with justification: you must describe the finding, localise it anatomically, generate a differential that respects the anatomy, and propose the next test. Structure answers as: modality and technique, systematic search, key finding, anatomical basis, differential, and recommendation.
Concepts to master
Understand anatomical pathways of spread - direct invasion along fascial planes, perineural spread (trigeminal and facial branches), lymphatic drainage by nodal station, and haematogenous routes. Know the imaging appearance of normal anatomy across modalities so you can recognise when a structure is displaced rather than abnormal. Learn the anatomical basis of clinical syndromes (cavernous sinus syndrome, Pancoast syndrome, Horner syndrome) because questions link a deficit to a lesion site.
Traps
- Anchoring on the obvious finding and missing a second, anatomically distant lesion.
- Ignoring the clinical localiser: a deficit defines the anatomical site before the image does.
- Misattributing a normal variant (e.g. an azygos lobe, a prominent cisterna magna) to disease.
- Recommending the wrong next test because the anatomical question (soft tissue vs bone vs vessel) was not defined first.
Worked example
A patient with a Pancoast tumour and hand weakness: localise the deficit to the lower trunk of the brachial plexus (C8–T1) as it crosses the thoracic inlet, then predict associated Horner syndrome from sympathetic chain involvement and hoarseness from recurrent laryngeal nerve involvement. The anatomical map generates the expected findings before the image confirms them.
Rule of thumb
Describe, localise, differential, next step - and always justify each step by naming the anatomical structure involved.