Normal MRI Anatomy Atlas
The structures you name in every report, region by region. Learn them here, then find them on the scanner. Pairs with the Search-Pattern Checklists.
On this page
Scroll through real scansBasal ganglia levelMidbrain level (“Mickey Mouse”)Pituitary & parasellar regionIAC / cerebellopontine angleKnee (midline sagittal)Rotator cuff & glenoidCouinaud segmentsZonal anatomy (PI-RADS)How to use this atlasSourcesScroll through real scans
Basal ganglia level
Brain: axial
- Head of caudate nucleus
- Lentiform (putamen + globus pallidus)
- Thalamus
- Third ventricle
- Genu of corpus callosum
- Frontal horn, lateral ventricle
On T1/T2: internal capsule separates caudate/thalamus (medial) from lentiform (lateral). The classic level for lacunar infarcts & the “wine-glass” of the CST.
Midbrain level (“Mickey Mouse”)
Brain: axial
- Midbrain (tectum + tegmentum)
- Cerebral peduncle (crus cerebri)
- Cerebral aqueduct
- Quadrigeminal (tectal) plate / colliculi
- Temporal horn, lateral ventricle
Watch: the interpeduncular & suprasellar cisterns sit anteriorly (star-shaped), a key review area for basal meningitis & SAH.
Pituitary & parasellar region
Sella: coronal
- Pituitary gland (in sella turcica)
- Infundibulum (stalk): should be midline
- Optic chiasm
- Cavernous sinus (CN III, IV, V1, V2, VI)
- Cavernous ICA flow void
- Sphenoid sinus
Dynamic protocol: microadenomas enhance slower than normal gland. Stalk deviation & gland height/convexity are key. See the Pituitary MRI page.
IAC / cerebellopontine angle
Posterior fossa: axial
- Pons
- Fourth ventricle
- Cerebellar hemisphere
- Internal auditory canal (CN VII/VIII)
- CPA cistern
Heavily T2 (CISS/FIESTA): nerves are dark filling defects in bright CSF. The go-to level for vestibular schwannoma (see the Case Library).
Knee (midline sagittal)
Knee: sagittal
- ACL: taut, straight, parallel to notch roof
- PCL: curved, low signal
- Meniscus (bow-tie on peripheral slices)
- Articular cartilage
- Patella
- Patellar tendon
Bow-tie rule: normal meniscal body = two bow-ties; fewer suggests a bucket-handle tear. Deep-dive on the Knee MRI page.
Rotator cuff & glenoid
Shoulder: oblique coronal
- Supraspinatus tendon (footprint on greater tuberosity)
- Humeral head
- Glenoid
- Labrum (inferior)
- Supraspinatus muscle belly
- Acromion
Fat-sat T2: fluid signal tracking into the tendon = tear. Assess muscle bulk on sagittal T1. More on the Shoulder MRI page.
Couinaud segments
Liver: Couinaud
Three hepatic veins divide the liver into four sectors; the portal vein plane splits each into upper/lower, giving eight segments numbered clockwise. Segment I (caudate) sits behind, draining directly to the IVC.
Why it matters: report every lesion by segment for the surgeon. The middle hepatic vein = Cantlie’s line (right vs left lobe). See liver search pattern.
Zonal anatomy (PI-RADS)
Prostate: axial zones
- Peripheral zone (PZ): ~70% of cancers; DWI-scored
- Transition zone (TZ): BPH; T2-scored
- Urethra / anterior fibromuscular stroma
- Neurovascular bundle (5 & 7 o’clock)
Remember: PZ = DWI dominant, TZ = T2 dominant. Full logic on the Reporting Templates (PI-RADS v2.1).
How to use this atlas
Learn the structures listed for each region, then run the matching search pattern on real studies. Real anatomy varies with slice, sequence and patient. Signal behaviour (what’s bright/dark on T1 vs T2 vs DWI) is covered in the Sequence Physics Explainer, and the structures you must actively check are listed in the Search-Pattern Checklists.
Educational use only.
Sources
Key references: Osborn AG, Diagnostic Imaging: Brain. Harnsberger, Diagnostic & Surgical Imaging Anatomy. Manaster, Diagnostic Imaging: Musculoskeletal. Federle, Diagnostic Imaging: Abdomen (Couinaud). Turkbey B et al., PI-RADS v2.1, Eur Urol 2019;76:340–351. Standard cross-sectional anatomy references (Radiopaedia; Weir & Abrahams, Imaging Atlas of Human Anatomy).