Examination 4
case 01
(a) Lesser tuberosity of the right humerus. The subscapularis tendon attaches here.
This may rarely become avulsed during hyper-external rotation injury due to traction
by the subscapularis tendon insertion.
(b) Greater tuberosity of the right humerus. This forms the bony footprint for the
supraspinatus tendon.
(c) Right acromion. The coraco-acromial ligament attaches from here to the coracoid
process, forming a roof over the shoulder joint. Bony enthesopathy of this
ligament may contribute to subacromial impingement of the supraspinatus
tendon and is implicated as a causative factor in the evolution of rotator cuff
tears.
(d) Right acromio-clavicular joint. This narrow synovial joint commonly undergoes
degenerative changes but may also develop erosions in inflammatory
arthropathy.
(e) The antero-inferior glenoid rim. This bears the attachment of the anterior band of
the inferior glenohumeral ligament, which is an important static stabilizer of the
glenohumeral joint. This region may be fractured during anterior glenohumeral
dislocation, producing a bony Bankart lesion.
case 02
(a) Medial collateral ligament (MCL). This important ligament arises from the medial
femoral condyle and inserts on the medial tibial diaphysis and resists valgus stress of
the knee.
(b) Posterior cruciate ligament. This strong ligament arises from the lateral
surface of the medial femoral condyle and inserts on the posterior intercondylar
fossa of the tibia. It is a central stabilizer of the knee resisting posterior tibial
translation.
(c) Iliotibial band (ITB). This long structure originates from the fascia of the iliotibial
tract and inserts on Gerdy's tubercle on the antero-lateral tibia. Distally it may
undergo repetitive friction over the lateral border of the lateral femoral condyle to
produce painful distal ITB friction syndrome.
(d) Articular cartilage of medial tibial plateau. This thick layer of hyaline cartilage
is composed of four zones or layers. During the evolution of osteoarthrosis the
chondral layers may undergo softening, fibrillation, fissures and progressive thinning,
ultimately resulting in full-thickness cartilage loss and sclerosis of the exposed
sub-chondral bone.
(e) Discoid lateral meniscus. The lateral meniscus is broad, spanning the whole width
of the lateral tibio-femoral compartment. This normal variant, if present, is frequently
bilateral and should be examined carefully due to the high incidence of degenerative
tears with this variant.
When looking at the coronal image of the knee without the fibula in view, the medial
aspect is determined by the relative abundance of subcutaneous fat compared with
the lateral aspect.
case 03
(a) Internal carotid artery. The internal carotid and external carotid arteries arise from
the bifurcation of the common carotid artery at C4 level. The internal carotid artery
gives off no branches in the neck while the external carotid artery gives off several.
Close to its origin the external carotid artery has two branches, the superior thyroid
artery arises anteriorly and the ascending pharyngeal artery arises medially.
(b) Occipital artery.
(c) Lingual artery. The lingual artery is the third branch of the external carotid artery
and runs anteriorly and supplies the tongue.
(d) Facial artery. The facial artery arises anteriorly, usually at the same level as the
occipital artery arises posteriorly.
The posterior auricular branch is the next branch that arises posteriorly to supply
the region of the pinna.
(e) Maxillary artery. The external carotid then divides to form the maxillary artery
and the superficial temporal artery.
case 04
(a) Left ischial spine.
(b) Spinous process of L2.
(c) Left psoas muscle.
(d) Right lobe of liver (segment 7).
(e) Lumbarization of S1. This is a common congenital abnormality of the lumbosacral
spine present in up to 12% of the population. The first sacral vertebra shows transition
to a lumbar configuration. A more common abnormality is sacralization, where the
fifth lumbar vertebra shows signs of assimilation to the sacrum.
There is no evidence to support that either abnormality predisposes to spinal
pathology.
Accurate numbering of the lumbar vertebrae can be an issue in this condition and is
best done counting down from the T12 vertebra.
case 05
(internal auditory meatus)
(a) Left cochlea. This is situated anteriorly within the inner ear, and consists of a spiral
canal and a cone-shaped modiolus.
(b) Left vestibule. This oval chamber is approximately 5 mm in length, and contains
the utricle and saccule, which form the vestibular organ responsible for maintaining
balance.
(c) Left lateral semicircular canal. The semicircular canals consist of lateral, anterior
and posterior divisions, which communicate with the vestibule of the bony labyrinth.
(d) Left vestibulo-cochlear nerve (VIII cranial nerve). The cochlear branch of this is
involved with hearing. The vestibular branch is involved with balance and is divided
into superior and inferior vestibular nerves.
The nerve lying anterior to the vestibulo-cochlear nerve is the facial nerve.
(e) Left cerebellar peduncle. The dorsal and ventral cochlear nuclei are found on the
lateral surface of the inferior cerebellar peduncle.
case 06
(a) This is the arterial branch which anastomoses with the superior mesenteric artery
(SMA) and is called the marginal artery (of Drummond).
(b) Ascending branch of left colic artery (or upper left colic artery).
(c) Left colic artery, middle branch.
(d) Superior rectal artery.
(e) Haemorrhoidal arteries. The inferior mesenteric artery (IMA) supplies the large
intestine from the splenic flexure to the upper rectum. The proximal territory forms a
watershed area with the middle colic artery and represents an area of vascular
vulnerability when blood flow is reduced by any cause. This is at the splenic flexure
and therefore the differential for a stricture in this lesion should include chronic
ischaemia.
In the elderly there are anastomoses, arcades seen at angiography, between the SMA
and IMA due to mesenteric arterial occlusion.
case 07
(a) The suspensory ligament of the duodenum (ligament of Treitz). This is a muscle
composed of a slip of skeletalmuscle that arises from the proximal part of the right crus
of the diaphragm as it encircles the oesophagus and inserts as a fibromuscular band of
smooth muscle into the third and fourth parts of the duodenum. Contraction widens
the angle of the duodeno-jejunal flexure helping the movement of bowel contents.
(b) Valvulae conniventes or circular folds (valves of Kerckring). These are reduplicated
bands of mucosa that extend into the lumen of the bowel, contain a fibrovascular
core of submucosa and extend completely around the whole circumference of
the intestine. The folds are more crowded in the jejunum and are deeper and thicker
than the ileum.
(c) Ileum. This typically makes up 60% of the small bowel and starts at 6 m.
(d) Gastric rugae. This is gastric mucosa thrown into longitudinal ridges. These are
most marked towards the pyloric region and along the greater curve of the stomach.
(e) Terminal ileum. This is the most distal part of the small intestine. The terminal
ileum enters the caecum obliquely at the ileo-caecal valve and partly invaginates into
it. It is of paramount importance to visualize this region in small bowel studies due to
the number of pathologies that occur here.
In a small bowel meal barium has been ingested by the patient and radiographs have
been taken at intervals. With a small bowel enema a nasogastric tube is passed and
barium introduced via this directly into the duodenum. Small bowel investigations
are being replaced by MR enteroclysis, which gives similar results without the need
for ionizing radiation. This is of relevance as many of these studies are carried out in
young patients with inflammatory bowel disease.
case 08
(a) Left atrium.
(b) Aortic root.
(c) Right coronary artery.
(d) Right inferior pulmonary vein.
(e) Aberrant left coronary artery. There are several normal variants of coronary artery
anatomy. The illustrated example is of an aberrant left coronary artery which has a
common origin with the right coronary artery from the right coronary cusp. Normally
the left coronary artery arises from the left coronary cusp.
In this case the aberrant left coronary artery has a ‘benign’ course passing anterior to
the right ventricular outflow tract (RVOT). If the aberrant artery runs a ‘malignant’
course between the aortic root and the RVOT this is associated with an increased
incidence of sudden cardiac death.
case 09
(a) Adenohypophysis or anterior pituitary gland. This is five times larger than the
posterior lobe, and produces hormones in response to hypothalamic releasing factors
that pass down a portal venous system into the lobe.
(b) Neurohypophysis or posterior pituitary gland. This is composed of nerve fibres,
extending from the supraoptic and paraventricular nuclei of the hypothalamus. Thus
hormones (vasopression, oxytocin) released by the posterior pituitary are actually
manufactured in the hypothalamus.
(c) Pituitary stalk. Also known as the infundibulum, this links the hypothalamus to the
pituitary gland. It is composed of nerve fibres of the hypothalamohypophyseal tract and
the venous portal system vessels that link the hypothalamus to the anterior pituitary.
(d) Optic chiasm. This is where the optic nerves (cranial nerve II) partially cross, and
is located immediately below the hypothalamus. This is clinically important since a
pituitary tumour can impinge on the chiasm leading to visual field disturbances.
(e) This is high signal because of the presence of neurosecretory granules in the
neurohypophysis such as vasopressin and oxytocin. Other structures typically seen
to be high signal on T1-weighted MR include:
MR contrast
melanin
fat
proteinaceous fluid
haemorrhage (due to methaemoglobin).
case 10
(a) Central zone of prostate.
(b) Right peripheral zone of prostate.
(c) Right levator ani muscle.
(d) Left ischio-anal fossa.
(e) Urinary bladder.
The prostate is divided into zones:
Peripheral zone contains 70% glandular tissue
Central zone contains 25% glandular tissue
Transition zone contains 5% glandular tissue.
T2-weighted MRI images depict prostatic zonal anatomy. The peripheral zone should
be seen as high signal on T2-weighted images in contrast to transitional and central
zones, which are of intermediate/low signal. The transitional and central zones
cannot be clearly separated with imaging.
Tumours occur in the peripheral zone where low signal lesions can be seen on
T2 imaging. MRI is often performed shortly after biopsy has occurred, and it is essential
to note any haemorrhagic change by carefully evaluating T1-weighted images, as this
can mimic tumour. If there are difficulties in MRI interpretation due to haemorrhage
and it is going to make a difference in patient management, repeat MRI may be needed.
Central zone hypertrophy leads to benign prostatic hyperplasia, which can cause
bladder outflow obstruction and lower urinary tract symptoms. The peripheral zone
will then appear compressed on MRI, and the central zone seen to contain areas of
low, intermediate and high signal.
case 11
(a) Capitellum.
(b) Radial head.
(c) Medial (or internal) epicondyle.
(d) Trochlea.
(e) Lateral epicondyle.
Ossification order and times:
Capitellum – in the first year
Radial head – 5 years
Medial epicondyle – 7 years
Trochlea – 9 years
Olecranon – 11 years
Lateral epicondyle – 13 years.
While there is wide variation in ossification timing, the order of appearance of
ossification is usually maintained, which therefore is more valuable to know rather
than the exact dates. Sexual dimorphism should be recognized with female elbows
usually ossifying and fusing earlier than males. The mnemonic CRITOL is an invaluable
reminder for this order.
The ossification order assumes significance because the medial epicondyle can be
avulsed and displaced into the joint. In this situation there will be an apparent
well-formed trochlea with no apparent ossification of the medial epicondyle, in a
child younger than 9 years. In an older child there may appear to be a fragmented
or bifid trochlea, but no medial epicondyle. There may be other clues to a significant
injury being present including soft tissue swelling or a joint effusion. However,
soft tissue swelling may be minimal as this injury is often an avulsion injury
and not direct trauma. A joint effusion may not be present if there is disruption of
the joint capsule allowing the effusion to escape into the soft tissues without
raising the anterior and posterior fat pads that are usually apparent with elbow
joint effusions. In some cases CT or MRI assessment may be required to confirm or
exclude injury.
case 12
(a) Duodenum – second part.
(b) Right external oblique muscle.
(c) Right inferior epigastric artery.
(d) Superior mesenteric artery.
(e) Left-sided component of a duplicated inferior vena cava (IVC).
A double IVC has a prevalence of up to 3% and comprises a right- and left-sided IVC,
which occur below the level of the renal veins. The two cavae join when the left-sided
component crosses the midline, usually anterior to the aorta to join the left renal vein,
which drains into the right-sided IVC. Occasionally the right renal vein may be retroaortic.
A left-sided infra-renal IVC is described, having a prevalence of up to 0.5%. As it
ascends, it crosses the midline anterior to the aorta as it joins the left renal vein.
The most important clinical problem in both anomalies is a tendency for misdiagnosis
as left para-aortic lymphadenopathy. It can rarely assume relevance in IVC filter
placement in which case bilateral iliac filters can be considered.
case 13
(a) Right superior rectus muscle.
(b) Right lateral rectus muscle.
(c) Right inferior rectus muscle.
(d) Left optic nerve.
(e) Left superior oblique muscle.
There are six extrinsic ocular muscles that insert into the sclera: four rectus muscles
(superior, inferior, medial and lateral recti), the superior oblique and inferior oblique.
These can be visualized on CT or MRI.
Ocular muscles may be affected in thyroid eye disease, in one or both orbits. The
inferior and medial rectus muscles are more likely to be involved first (mnemonic that
gives the order of extraocular muscle involvement – I'M SLow – inferior, medial,
superior, lateral). Swelling occurs involving the belly of the muscles but sparing of the
tendon, whereas in orbital pseudotumour or myositis, the anterior tendinous portion
is also involved.
Note the presence of mucosal thickening in the maxillary sinuses.
case 14
(a) Left ventricle.
(b) Fundus of stomach.
(c) Inferior vena cava (IVC). The IVC passes through the central tendon of the diaphragm
at T8 together with the right phrenic nerve. The oesophagus passes through
the diaphragm at T10 together with the right vagus nerve posteriorly and the left
vagus nerve anteriorly. The aortic opening is at T12 through which also passes the
thoracic duct. Other structures which pass through the diaphragm are the left phrenic
nerve, splanchnic nerves and the sympathetic chain behind the arcuate ligaments.
(d) Right portal vein. The proximity of the portal vein to the hepatic vein allows for a
Transjugular Intrahepatic Porto-systemic Shunt (or TIPSS) procedure. With cirrhosis
of the liver there is raised venous pressure in the liver bed which transmits to the
portal circulation and collateral pathways develop. In particular, there is risk of
catastrophic gastrointestinal haemorrhage from oesophogeal varices. A TIPSS procedure
shunts blood into the systemic circulation thereby reducing portal pressure. It
involves placing a covered stent between the right portal vein and right hepatic vein
via a jugular approach.
(e) Right hepatic vein.
case 15
(a) Superficial femoral artery. Distally this lies in the adductor canal lying on
adductor longus, then adductor magnus, becoming the popliteal artery as it passes
through the adductor hiatus in latter muscle.
(b) Popliteal artery. The popliteal artery branches into its end arteries at the lower
border of popliteus in 95% of individuals. However, in particular, there is variability
in the level of branching of the anterior tibial artery.
(c) Posterior tibial (PT) artery. The segment of vessel between the popliteal artery and
bifurcation of the PT and peroneal artery is referred to as the tibio-peroneal trunk.
(d) Fibular (common peroneal) artery. Normally the fibular (peroneal) artery terminates
in the distal calf.
(e) Anterior tibial artery. The anterior and posterior tibial arteries continue into the
foot as the dorsalis pedis and lateral plantar arteries respectively.
case 16
(a) Left main bronchus.
(b) Right pulmonary artery.
(c) Left pulmonary artery. The left pulmonary artery is posterior to the right pulmonary
artery on the lateral projection and lies superior to the relatively horizontally
orientated left main bronchus, which appears as an oval lucency (A).
(d) Posterior tracheal stripe. The posterior tracheal stripe should be no greater than
2.5 mm in thickness when the posterior tracheal wall coming into contact with the
upper lobe forms the stripe. The posterior tracheal stripe will be up to 5.5 mm
thickness if there is apposition of the anterior oesophageal wall and the posterior
trachea.
Raider's (retrotracheal) triangle is bounded by the thoracic inlet superiorly,
aortic arch inferiorly, the spine posteriorly and the posterior tracheal stripe anteriorly.
(e) Left hemidiaphragm. Determining the side of the hemidiaphragm on the lateral
film is reasonably straightforward. The diaphragm that is ‘lost’ under the cardiac
silhouette is the left hemidiaphragm because it has the same radiographic density as
the heart. If the gastric bubble is above one hemidiaphragm and below another, then
it is below the left hemidiaphragm (if the gastric bubble is below both hemidiaphragms,
this method cannot be used to determine the side).
case 17
(a) Left serratus anterior muscle.
(b) Left latissimus dorsi muscle.
(c) Oesophagus.
(d) Right ventricle.
(e) Right inferior pulmonary vein.
The pulmonary veins enter the left atrium almost perpendicular to the lateral atrial
walls. The inferior and superior pulmonary veins enter the atrium very close to each
other.
Pulmonary veins run in the interlobular septa along with lymphatics. They enter
the left atrium at the hilum and may enter the atrium separately – one for each lobe –
or may conjoin before entering the atrium.
Pulmonary veins lie anterior to pulmonary arteries bilaterally.
case 18
(a) Frontal sinus.
(b) Dorsum sellae.
(c) Adenoidal tissue.
(d) Cruciate ligament of atlas.
(e) Hard palate.
case 19
aorta
(a) T12 vertebral body.
(b) Aorta.
(c) Left gastric artery.
(d) Coeliac axis.
(e) Superior mesenteric artery (SMA). The SMA comes off at L1, which is known as
the transpyloric plane of Addison. Its usefulness is in the number of structures which
lie in this plane:
Pylorus of stomach
Fundus of gallbladder
Neck of pancreas
Renal pelvis
Termination of spinal cord
Ninth rib.
The lateral projection is key when working out at what levels the splanchnic branches
arise as well as their cranio-caudal angulation for catheter placement. Therefore any
planning for mesenteric angiography should be undertaken on a preceding CT.
case 20
Please note the side marker!
(a) Left pericardial fat pad. This is of no clinical bearing but can sometimes be
confused for a mediastinal mass because of its shape. The density of a fat pad is less
than that produced by soft tissue mass lesions.
(b) Left main bronchus.
(c) Right first rib.
(d) Right costophrenic angle.
(e) Situs inversus. The radiograph has been presented the wrong way round but the
side marker is present on the film.
Situs inversus implies the position of the heart is mirrored as is that of the abdominal
viscera. Normal position is referred to as situs solitus.
If solely the position of the heart is altered, with the apex towards the right, then
this is referred to as dextrocardia.
Kartagener's syndrome is a not infrequent association with situs inversus, affecting
20% of patients. It is a disease affecting mucociliary function and therefore patients
often present with sinusitis and bronchiectasis.
Situs inversus also has bearing on patients presenting with trauma or abdominal
pain and it needs to be considered, for instance, the spleen will be on the right and the
appendix on the left.
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