Coronal CT of the sinuses

1. A Crista galli.

2. B Right infraorbital foramen.

3. C Right inferior turbinate.

4. D Hard palate.

5. E Right infraorbital nerve, artery or vein.

‘Crista galli’ is Latin for ‘crest of the cock’. It is a midline ridge of bone that projects from the cribriform plate of the ethmoid bone. The falx cerebri attaches here, and the olfactory bulbs lie on either side. The infraorbital foramen transmits the infraorbital nerve, artery and vein, which can be damaged or compressed in orbital blowout fractures. The infraorbital nerve is a branch of the maxillary nerve, which is the second division of the trigeminal nerve (CN V).

There are three turbinates; superior, middle and inferior. They function to control the flow of air and ensure that even air humidification and warming takes place over an increased surface area. The osteomeatal complex is a functional entity that includes the middle turbinate, uncinate process, bulla ethmoidalis, hiatus semilunaris and ethmoid infundibulum. It is the common pathway for drainage and ventilation of the frontal, maxillary and ethmoid sinuses.

MR angiogram of the neck

1. A Right vertebral artery.

2. B Right common carotid artery.

3. C Right internal thoracic artery.

4. D Left common carotid artery.

5. E Left vertebral artery.

The paired vertebral arteries are branches of the first part of the subclavian arteries and course through the transverse foramen of each cervical vertebra from C6 to C1. After C1, the vertebral arteries pass through the suboccipital triangle and enter the foramen magnum.

Axial CT of the brain

1. A Falx cerebri.

2. B Right middle cerebellar peduncle.

3. C Right cerebellar hemisphere.

4. D Left tentorium cerebelli.

5. E Pons.

The falx cerebri is a scythe-shaped fold of dura mater in the longitudinal fissure between the two cerebral hemispheres. It attaches anteriorly to the crista galli of the ethmoid and posteriorly to the upper surface of the tentorium cerebelli. The tentorium cerebelli is a tent of dura that separates the cerebellum from the inferior portion of the occipital lobe, thus defining the supratentorial and infratentorial spaces.

The cerebellum is connected to the rest of the central nervous system by three pairs of nerve tracts known as cerebellar peduncles. The inferior cerebellar peduncles connect the medulla spinalis and medulla oblongata with the cerebellum. They form a thick strand between the lower part of the fourth ventricle and the roots of the ninth and tenth cranial nerves. The middle cerebellar peduncles connect the pontine nuclei to the contralateral cerebellum. Their fibres are arranged in three fasciculi – superior, inferior and deep. The superior cerebellar peduncles connect the cerebellum to the midbrain. They form the upper lateral boundaries of the fourth ventricle. The anterior medullary velum connects the superior cerebellar peduncles, and between them they also form the roof the fourth ventricle.

Axial CT scan of the brain

1. A Frontal horn of the left lateral ventricle.

2. B Anterior limb of the right internal capsule.

3. C Head of the left caudate nucleus.

4. D Left thalamic nucleus.

5. E Pineal gland.

The heads of the caudate nuclei are located in the concavities of the frontal horns of the lateral ventricles. The internal capsule lies lateral to the caudate nucleus and is split into anterior and posterior limbs. The anterior limb is located between the caudate nucleus and the globus pallidus of the lentiform nucleus. There are two thalami, which are located lateral to the third ventricle and medially to the posterior limb of the internal capsule. The pineal gland is a midline structure located posterior to the third ventricle and is often calcified.

Sagittal T1 MRI scan of the brain

1. A Frontal sinus.

2. B Optic chiasm.

3. C Pons.

4. D Prepontine cistern.

5. E Soft palate.

The paired frontal sinuses lie superior to the nose and orbits and are located between the inner and outer tables of the frontal bone. The two optic nerves partially decussate at the optic chiasm in the middle cranial fossa. The brainstem consists of the medulla oblongata, pons and midbrain. The pons can be recognized on sagittal imaging by its bulging anterior surface, in front of which is the prepontine cistern (one of the subarachnoid basal cisterns, located between the pons and the clivus).

Axial CT of the upper neck with IV contrast

1. A Right lateral pterygoid plate.

2. B Right mandibular condyle.

3. C Left internal carotid artery.

4. D Left styloid process.

5. E Left vertebral artery.

The lateral and medial pterygoid plates are part of the sphenoid bone and descend perpendicularly from the region where the body and the greater wings unite. All categories of Le Fort fracture involve the pterygoid plates. The internal carotid artery arises at the level of C3 (where the common carotid artery bifurcates) and enters the base of the skull through the carotid canal. The styloid process is a pointed thin piece of bone that extends from the inferior surface of the temporal bone and serves as an important attachment to several ligaments and muscles of the larynx and tongue. The vertebral arteries are paired arteries that usually arise from the subclavian arteries and course through the foramen transversarium from C6 to C1. This image demonstrates the path of the vertebral arteries as they enter the foramen magnum, where they unite to form the basilar artery.

Lateral X-ray of the skull

1. A Posterior clinoid process.

2. B Sella turcica (pituitary fossa).

3. C Sphenoid sinus.

4. D Frontal sinus.

5. E Hard palate.

The sella turcica is a depression within the sphenoid bone that houses the pituitary gland. The anterior border is formed by two small bony eminences called the anterior clinoid processes.

Coronal T2 MRI of the brain

1. A Temporal horn of right lateral ventricle.

2. B Third ventricle.

3. C Left hippocampus.

4. D Right cochlea.

5. E Left parotid gland.

The lateral ventricles drain cerebrospinal fluid into the third ventricle via the right and left interventricular foramen (foramen of Munro). The third ventricle drains into the fourth ventricle via the cerebral aqueduct (aqueduct of Sylvius). The fourth ventricle drains via a central foramen of Magendie and two lateral foramina of Luschka.

The hippocampus is a key part of the limbic system and is seen as a curved prominence on the inferior horn of the lateral ventricle. It is a grey-matter structure with a thin covering of white matter, which is known as the alveus.

For more information and a flow diagram of the ventricular system see Question 4.2.

Coronal T1 MRI of the brain

1. A Right sylvian fissure.

2. B Right caudate nucleus.

3. C Septum pellucidum.

4. D Left putamen.

5. E Right lateral mass of C1.

The septum pellucidum is a thin membrane separating the anterior horns of the lateral ventricles. It consists of two layers of both white and grey matter, called the laminae septi pellucidi. During foetal development there is a space between these two laminae called the cavum septum pellucidum. This is fused in 85% of individuals by six months of age but can persist into adulthood as a normal variant.

Sagittal T1 MRI of the brain

1. A Mammillary body.

2. B Fourth ventricle.

3. C Tectum of the midbrain.

4. D Tentorium cerebelli.

5. E Cerebellar tonsil.

The mammillary bodies are a pair of rounded prominences at the anterior arches of the fornix. They are part of the limbic system. They can be damaged as a result of thiamine deficiency (Wernicke–Korsakoff syndrome). The fourth ventricle is the most inferior of the ventricular spaces and is diamond-shaped in cross section. It connects to the third ventricle via the aqueduct of Sylvius, and drains via the foramen of Luschka (two lateral tracts) and the foramen of Magendie (single midline tract). The tectum is located at the dorsal region of the midbrain and consists of superior (visual) and inferior (auditory) colliculi. There is a cerebellar tonsil on the undersurface of each cerebellar hemisphere in continuity with the uvula of the cerebellar vermis. It is helpful to assess these on sagittal section to look for elongation and descent of the cerebellar tonsils into the foramen magnum, which can be associated with raised intracranial pressure or congenital malformations (Chiari malformations).

Axial T2 FLAIR MRI of the brain

1. A Right external capsule.

2. B Choroid plexus in the right lateral ventricle.

3. C Splenium of the corpus callosum.

4. D Left caudate nucleus (head).

5. E Left lentiform nucleus.

In 2010 the Royal College of Radiologists reintroduced the anatomy component of the FRCR Part 1 examination. The primary aim of this book is to provide trainee radiologists with a focused and invaluable revision aid when preparing for this exam. Its utility is not just limited to radiologists, however, and other groups such as radiographers and medical students will also find the detailed images and descriptions helpful to their studies. This book was written to be complementary to existing formal anatomy texts, and is intended to be used in conjunction with them.

The ten mock examinations within this book have been designed to closely conform with the new syllabus set out by the RCR. Each exam is laid out and structured in the same way as the actual papers, ensuring that readers will gain familiarity with both the content and the style of the examination. By the end of the book, readers will have encountered every imaging modality and the majority of cases covered in the exam itself. The answer sections include detailed explanations of the relevant anatomy, along with helpful learning tips and clinical applications.

The anatomy syllabus is available on the college website and should be studied closely. It is broadly divided into four categories: head and neck; thorax; abdomen and pelvis; and musculoskeletal system. Candidates can expect the examination to have roughly equal proportions from each category in the examination.