RANZCR Anatomy cheat sheet

Corticobulbar fibres descend through the genu of the internal capsule; corticospinal fibres traverse the posterior limb, somatotopically ordered arm, trunk, leg from anterior to posterior.

Broca area lies in the pars opercularis and triangularis of the inferior frontal gyrus of the dominant hemisphere; Wernicke area occupies the posterior superior temporal gyrus.

The hippocampus is the medial rolled structure above the parahippocampal gyrus, separated from it by the hippocampal sulcus; the choroid fissure lies superomedially.

The internal auditory canal transmits cranial nerves VII and VIII plus the labyrinthine artery; its posterior wall separates it from the vestibular aqueduct.

The parotid gland lies lateral to the masseter and mandible; the facial nerve divides it into superficial and deep lobes, with the retromandibular vein as the surgical landmark.

Deep neck spaces communicate: the retropharyngeal space spans skull base to T4 (danger space to diaphragm), and the parapharyngeal space is the central crossroads for spread.

Bronchial segmentation: right main bronchus gives upper, middle, lower lobar bronchi; the left gives upper and lower, with the lingula replacing the middle lobe.

Coronary dominance is defined by the artery supplying the posterior descending artery: right in ~85%, left (circumflex) in ~8%, codominant in ~7%.

Hepatic segments follow the portal venous and hepatic venous planes (Couinaud I–VIII); the caudate (I) drains directly into the IVC and is spared in Budd-Chiari.

Bowel obstruction: small bowel >3 cm, colon >6 cm, caecum >9 cm; presence of gas in the rectum argues against complete obstruction.

Pancreatitis (revised Atlanta): interstitial oedematous versus necrotising; local complications include acute peripancreatic fluid collection, pseudocyst (>4 weeks), walled-off necrosis.

Pulmonary embolism: CTPA filling defect; right ventricular/left ventricular ratio >1.0 on axial images indicates right heart strain and worse prognosis.

Stroke: ASPECTS ≤6 or large core on CT perfusion predicts poor outcome and influences thrombectomy eligibility; penumbra is perfusion lesion minus core.

Thyroid nodule risk: TIRADS uses composition, echogenicity, shape, margin and echogenic foci; punctate echogenic foci and lobulated margins raise category.

Bone tumour location rules: epiphysis (chondroblastoma, GCT), metaphysis (osteosarcoma, osteochondroma), diaphysis (Ewing, lymphoma); age <30 favours benign.

Liver lesion pattern: arterial hyperenhancement with portal venous washout indicates HCC in cirrhosis; peripheral nodular enhancement with centripetal fill-in indicates haemangioma.

Renal mass: clear cell RCC is hypervascular and may show macroscopic fat rarely; papillary RCC is hypovascular and T2 hypointense; chromophobe shows a central scar.

Adrenal incidentaloma: >10 HU on unenhanced CT suggests lipid-poor lesion; absolute washout >60% at 15 minutes favours adenoma.