Examination 1
case 01
(a) Left brachiocephalic vein. The left brachiocephalic vein forms a silhouette with the
adjacent lung. This interface ‘fades’ above the clavicles as it becomes more anteriorly
placed and ‘merges’ with the anterior chest wall.
(b) Pulmonary trunk.
(c) Right atrium (right heart border).
(d) Right cardiophrenic recess.
(e) Azygos fissure. The azygos fissure is seen in 0.5% of chest radiographs. It is
formed by the caudal invagination of the azygos vein through the apex of the right
upper lobe. It begins as a line in the upper portion and extends in an arc caudally
toward the ‘teardrop’ density that is the azygos vein. The azygos vein is outside the
parietal pleura – the line is therefore composed of two visceral and two parietal
pleural layers. The so-called azygos ‘lobe’ is the segment of lung between the fissure
and the trachea. It is not a true separate ‘lobe’ as the total bronchial anatomy in the
right upper lobe has not been altered even though there may be minor variations in
the bronchial supply to this segment of upper lobe.
case 2
anterior fontanelle
(a) Left lateral ventricle. The combined width of the lateral ventricles on coronal
imaging should be less than a third of the total width of the intracranial fossa at the
same level.
(b) Corpus callosum.
(c) Superior sagittal sinus. Colour flow and Doppler can be used to assess venous
sinus patency.
(d) Right temporal lobe.
(e) Pons.
Ultrasound of the neonatal brain is a very useful non-invasive diagnostic test that
does not utilize ionizing radiation.
The acoustic windows utilized include:
Anterior fontanelle until its closure at 2 years, allowing coronal and sagittal
imaging of the supratentorial brain.
Posterior fontanelle up until its closure at 2 months, allowing axial imaging of the
supratentorial brain.
Temporal or sphenoidal fontanelle until its closure at 3 months, allowing
axial imaging of the brainstem and colour flow and Doppler of the circle of
Willis.
Mastoid fontanelle allowing imaging of the posterior fossa. The mastoid process
develops in the second year. The fontanelle closes towards the end of the first
year.
Focal echogenic change can be related to parenchymal ischaemia or haemorrhage.
Parenchymal cystic change is also well demonstrated.
case 3
(a) Quadriceps tendon. This is formed by the combination of the vastus medialis,
vastus intermedius, vastus lateralis and rectus femoris tendons. Rupture of this
structure results in loss of knee extension.
(b) Anterior cruciate ligament (ACL). This is an important central stabilizer of the
knee joint, limiting anterior tibial translation. Failure of the ACL may occur due to
tears at the origin or within the mid-substance, or less commonly following avulsion
of the footprint antero-lateral to the anterior tibial spine.
(c) Posterior cruciate ligament (PCL). The PCL is a strong ligament with a recently
described 4-bundle structure. Tears of this ligament most commonly occur in the midsubstance.
(d) Patellar tendon. This inserts onto the tibial tuberosity. In the clinical setting of
recurrent lateral patellar dislocation, the patellar tendon insertion is surgically medialized
by a procedure called a ‘Tibial tuberosity transfer’. This reduces the degree of
lateral patellar migration during knee flexion.
(e) Posterior mensico-femoral ligament (of Wrisberg). Either the posterior (Wrisberg)
or anterior (Humphrey) mensico-femoral ligaments are present in 80% of knees. They
stabilize the posterior horn of the lateral meniscus and must not be mistaken for
displaced meniscal tear fragments on sagittal MRI images.
case 4
(a) Left lobe of the thyroid gland. Each lobe measures approximately 4 cm in height,
and extends from the thyroid cartilage of the trachea (superiorly), to the sixth tracheal
ring (inferiorly).
The recurrent laryngeal nerve runs posterior to this. This can be identified on
ultrasound as a linear hypoechoic structure between the thyroid anteriorly and the
longus collis muscle posteriorly.
(b) Cervical oesophagus. This lies slightly to the left of the trachea and can
be confused as a mass. It is readily identified by the central echobright area
representing the air and saliva in the lumen. The surrounding hypoechoic rim is
muscle.
(c) Left common carotid artery. This divides into external and internal branches at the
upper border of the thyroid cartilage, at approximately C4 level. The vagus nerve
(cranial nerve X) runs in the carotid sheath in the infrahyoid part of the neck.
(d) Left internal jugular vein. This originates as a continuation of the sigmoid sinus
and continues in the carotid sheath as it descends down the neck.
(e) Left sternocleidomastoid muscle. The muscle is a powerful rotator of the neck.
Birth trauma may be associated with muscle damage, leading to contraction of the
muscle causing congenital torticollis.
case 5
(a) Genioglossus muscle. This large fan-shaped muscle forms the bulk of the tongue.
It arises from the superior mental spine on the inner surface of the mandible and
inserts along the entire length of the undersurface of the tongue. Its relaxation during
sleep is thought to contribute to sleep apnoea.
(b) Right submandibular gland. This image shows an axial view through the floor of
the oropharynx. The submandibular duct (‘Wharton's duct’) opens in the floor of the
mouth on either side of the frenulum.
(c) Spinal cord.
(d) Left sublingual gland. The sublingual glands lie anterior to the submandibular
gland under the tongue, beneath the mucous membrane of the floor of the mouth. Its
acini secrete mucous fluid and it receives secreto-motor nerve supply from the chorda
tympani nerve.
(e) Left parotid gland. The parotid glands are relatively fatty in appearance and
therefore are high signal on T2-weighted and T1-weighted images.
A number of key structures run through the parotid gland including the terminal part
of the external carotid artery (often giving off its two terminal branches, maxillary
artery and the superficial temporal artery inside the gland), the retromandibular vein
and branches of the facial (VII) nerve.
The facial nerve runs superficial to the artery and vein and divides into its five
terminal branches in the gland.
Inflammation of the gland causes parotitis, often the consequence of a calculus
blocking the parotid duct. Mumps may also cause painful parotitis.
case 6
(a) Symphysis pubis. This is a cartilaginous joint between the two pubic bones whose
articular surfaces are covered by hyaline cartilage. A fibrocartilaginous disc connects
two surfaces allowing virtually no movement to take place.
(b) Urethra. The female urethra is usually 4 cm in length. On T2-weighted images the
urethra is seen as concentric rings of different signal intensities, giving the appearance
of a target.
(c) Vagina. Its lower third runs parallel to the urethra. Typically it shows an H-shaped
appearance on transverse MRI. The mucosal layer shows high signal intensity on
T2-weighted, muscular layer shows low signal intensity on T1-weighted and the outer
adventitial layer has a high signal intensity on T2-weighted imaging.
(d) Right internal pudendal artery and veins. The structure is called the (right) ischioanal
fossa (ischio-rectal fossa). It is filled with dense fat allowing the anal canal to
distend during defaecation. The pudendal nerve runs inside the pudendal canal
(Alcock's canal), which is situated in the lateral wall of the ischio-anal fossa. It also
contains the internal pudendal artery and veins.The inferior rectal artery, vein and
inferior anal nerves also cross the fossa transversely. The ischio-anal fossa is bounded
laterally by obturator internus.
(e) Left levator ani muscle. This thin muscle arises from the posterior surface of the
superior ramus of the pubis and forms the medial boundary of the ischio-anal fossa. It
merges with the muscle from the opposite side, the coccyx and inserts into the rectum.
case 7
(a) Aortic root.
(b) Left main coronary artery. The left main coronary artery arises from the left
coronary cusp. It bifurcates into the left anterior descending artery (LAD), which runs
in the anterior inter-ventricular groove, and the left circumflex artery (LCX), which
runs in the left atrio-ventricular groove.
(c) Left atrial appendage.
(d) Ramus intermedius. Occasionally (as in this case) there is a third branch from the
distal left main, the ramus intermedius.
(e) Left anterior descending artery.
The LAD gives rise to diagonal branches which run over the surface of the left
ventricle (LV) and also to septal perforator branches which are not well demonstrated
on CT angiography (CTA). The LCX gives rise to obtuse marginal branches which run
along the lateral border of the LV.
case 8
(a) Transverse colon. This can be seen to cross the midline anteriorly on axial CT. It
has a mesentery, the mesocolon, which attaches it to the posterior abdominal wall and
on which it hangs between the fixed points of the hepatic and splenic flexures.
(b) Right psoas muscle. The psoas muscles are paired and lie lateral to the lumbar
vertebrae, descending anteriorly to fuse with the iliacus muscle. A psoas abscess can
develop due to the close proximity of structures to the muscle. Common origins of
these abscesses include the vertebral column, expanding perinephric abscesses and
bowel-related complications, such as diverticulitis.
(c) Left quadratus lumborum muscle.
(d) Left kidney. The kidneys are retroperitoneal. The hilum of the left kidney normally
lies at L1 vertebral level, with the right renal hilum at the level of L1/L2 due to
the liver lying superior to it. Anterior relations of the left kidney include stomach,
pancreas, spleen, splenic flexure and small bowel loops.
(e) Left-sided inferior vena cava (IVC).
Normal variants are relatively common in the abdomen and include variants in
vascular anatomy. Although this image is unenhanced, the IVC can be seen to lie
on the left of the aorta. The aorta calcifies whereas the IVC does not, as can be seen in
this image.
It is important to include any variants in vascular anatomy when constructing a
radiological report as a surgeon needs to know this prior to embarking on a renal or
other retroperitoneal procedures.
case 9
(a) Penile urethra. The male urethra runs from the neck of the bladder to the urethral
orifice at the tip of the penis. The penile and bulbous urethra constitute the anterior
urethra.
(b) Lesser trochanter of the right femur.
(c) Membranous urethra.
(d) Prostatic urethra. The membranous and prostatic urethra constitute the posterior
urethra.
(e) Urinary bladder (collapsed).
Urethrograms are performed by placing a small catheter in the fossa navicularis,
gently inflating the balloon and slowly injecting contrast to outline the urethra. By
placing the patient obliquely on the x-ray screening table this allows the penile
urethra to be elongated and ensures adequate views of the entire urethra.
Proximal urethral injuries are seen with pelvic fractures as the distal prostatic and
membranous urethra has a fixed attachment to the pelvic bones. It is important to
perform retrograde (cystogram through suprapubic catheter) and antegrade
(ascending urethrogram) studies in a patient at risk of urethral trauma to ensure there
is direct continuity between the bladder and the entire urethra.
case 10
(a) Left common femoral artery (CFA). This lies in the femoral sheath together with
the femoral vein, which is medial to it. The femoral nerve is lateral to the sheath
(mnemonic NAVY; N=nerve, A=artery, V=vein, Y¼y-front). This sheath, made up
of transversalis fascia anteriorly and fascia iliacus posteriorly, tapers and fuses with
the vessel walls after approximately 2 cm.
The CFA is punctured at the site of maximal pulsation, usually the mid-inguinal
point, halfway between the anterior superior iliac spine and pubic tubercle. While this
is often described as the point of the mid-inguinal crease, it may be deceptive in old or
obese patients.
(b) Left deep artery of the thigh (profunda femoris artery). This is the major arterial
supply to the thigh and if the superficial artery is occluded then this vessel can supply
the whole leg via collateralization to the superficial femoral artery (SFA).
A puncture too low will often result of cannulation of this vessel, increasing the risk
of pseudoaneurysm formation.
(c) Left superficial femoral artery. This vessel is the main supply to the calf and foot.
In patients with peripheral vascular disease this along with the iliac vessels is a
common site for stenoses or occlusion. The SFA lies medial and anterior to the
profunda and therefore the arterial needle should be directed that way on puncturing
the CFA.
(d) Left lateral circumflex femoral artery.
(e) Left superficial circumflex iliac artery. A retrograde puncture of the CFA needs to
be below this vessel to be below the inguinal ligament. This is of importance as the
femoral head lies behind this segment of the CFA and therefore haemostasis can be
secured by manual compression against a bony structure.
case 11
with 30 degrees angulation)
(a) Temporal process of the right zygomatic bone. This meets the zygomatic process
of the temporal bone to form the zygomatic arch or cheek bone. Temporalis muscle
passes medial to the arch to attach at the coronoid process of the mandible.
(b) Right head of mandible. This is best seen on orthopantomogram (OPG) views or
dedicated mandibular views. It articulates with the mandibular fossa of the temporal
bone to form the temporomandibular joint (TMJ). These are best visualized with MR.
This joint lies immediately anterior to the external auditory meatus; therefore trauma
to the mandible often results with haemorrhage into the meatus which can be
confused with intracerebral trauma.
(c) Odontoid peg or dens. This is part of C2 (atlas) and articulates with C1 (axis) at the
atlanto-axial joint.
(d) Left coronoid process of the mandible.
(e) Left maxillary sinus. The anatomy on facial films is complex and symmetry is
often useful to facilitate evaluation.
case 12
(a) Aortic arch. The ascending aorta extends to the branch of the right brachiocephalic
artery and the descending aorta commences at the distal aspect of the left subclavian
artery. The aortic arch lies between these two points.
(b) Right internal thoracic (or mammary) artery. This is the first branch of the
subclavian artery and can act as a bypass conduit in aortic occlusion via the inferior
epigastric artery. This is known as the path of Winslow.
(c) Right brachiocephalic (or innominate) artery.
(d) Right vertebral artery. This arises from the subclavian artery. The subclavian
‘steal’ syndrome occurs when there is a subclavian stenosis distal to the origin of
the vertebral artery. The arm ‘steals’ its blood supply from the vertebral artery.
(e) Common origin of the left common carotid and innominate artery (bovine
arch). This occurs in 22% of individuals and accounts for 73% of all arch vessel
anomalies.
Other common variants include left vertebral artery arising directly from the aortic arch
(6% of individuals), thyroid ima artery (6%) and aberrant right subclavian artery (1%).
case 13
(a) Anterior junction line. This is formed by the interface of the anterior lungs as they
meet in the midline. This line will only be seen on the frontal projection if there is
sufficient penetration of the beam, which should be tangential to the interface. The
line runs below the aortic arch and to the left in a caudal direction.
(b) Azygo-oesophageal line. This is formed by the interface between the right lung
and the azygos vein and oesophagus. The cranial end of the line terminates at the
point where the azygos vein drains into the superior vena cava. Any bulge of this line
is indirect evidence of a possible oesophageal or posterior/middle mediastinal mass
lesion and before the advent of cross-sectional imaging, this was sometimes the only
plain radiograph sign of such pathology.
(c) Right interlobar pulmonary artery.
(d) Descending thoracic aorta.
(e) Right transverse process of the C7 vertebra. The transverse process of a cervical
vertebra points downwards unlike that of a thoracic vertebra, which points upwards.
This is a useful fact to remember when determining whether an atypical rib is a
cervical or hypoplastic first rib. In the case of a cervical rib, the rib articulates with a
transverse process that is pointing downwards.
case 14
(a) Appendix.
(b) Right femoral artery.
(c) Right psoas muscle.
(d) Right inferior epigastric artery.
(e) Right femoral nerve.
The normal appendix should measure less than 6 mm in its maximum diameter.
There is often a trace of free fluid in the right iliac fossa with appendicitis.
Careful exclusion of a faecolith should be undertaken.
The fat surrounding the appendix should be echogenic and freely compressible.
Colour flow Doppler signal should be the same as for the rest of the adjacent bowel.
Enlarged mesenteric lymph nodes may be apparent and may point to the alternative
diagnosis of mesenteric adenitis.
A collection in the right iliac fossa or a pelvic collection anterior to the rectum is
often appendix related.
Compression over the inflamed appendix will result in pain and rebound tenderness
can often be elicited.
case 15
(a) Manubrio-sternal joint (sternal angle). The manubrio-sternal joint is a secondary
cartilaginous joint and may be involved with generalized seronegative arthropathies.
Anatomically, it normally lies at the level of the T4–T5 intervertebral disc and the
aortic arch.
(b) Medial clavicle.
(c) Head of humerus.
(d) Body of sternum.
(e) Manubrium.
case 16
(a) Optic chiasm.
(b) Nuchal ligament.
(c) Interspinous ligament.
(d) Aortic arch.
(e) Aberrant right subclavian artery. (Black spherical structure lying anterior to
T2/T3.) Arterial blood flow on T1-weighted images produces a signal void. The blood
vessel posterior to the oesophagus is the aberrant right subclavian artery. This is a
normal variant if it is of normal calibre. When aneurysmal, this artery may cause
dysphagia – the so-called dysphagia lusoria, which literally means ‘unusual dysphagia’.
An aberrant right subclavian artery causes a posterior impression on the oesophagus
during a barium swallow.
case 17
(a) Fundus of the uterus. This is the part of the uterus that lies above the entrance to the
fallopian tubes. The body of the uterus lies belowthe fundus andmerges with the cervix.
(b) Isthmus of the left fallopian tube. This is the narrowest part of the tube lying just
lateral to the uterus.
(c) Right cornu of the uterus (uterine horn).
(d) Right sacroiliac joint. This is a synovial joint formed between the auricular surfaces
of the sacrum and the iliac bones. A small but limited amount of movement occurs at
this joint. An important anterior relationship is the ureter which passes over it.
(e) Ampulla of the left fallopian tube (the widest part). The uterus is almost entirely
covered with peritoneum (the broad ligament) except at the anterior part of the cervix.
The peritoneum reflects over the posterior wall of the bladder at the level of the internal
cervical os, leaving the anterior cervix without a peritoneal covering.
The uterus is held in position within the pelvis by condensations of endopelvic fascia
or ligaments that include the pubocervical, transverse cervical ligaments and the
uterosacral ligaments.
case 18
(a) Left vertebral artery.
(b) Left subclavian artery.
(c) Left pulmonary artery.
(d) Carina.
(e) Aortic knuckle (arch).
A CT scan can be seen to be enhanced when there is contrast in the vessels. usually the
thorax is scanned in the arterial phase and thereby there will be contrast in the
arteries. (There will be residual denser contrast within the superior vena cava (SVC)
from the venous administration.) The abdomen is commonly scanned in portal
venous phase (60–70 second delay after administration of contrast), which means
the portal vein will enhance more avidly compared to the arteries.
case 19
(a) Right renal artery.
(b) Lumbar vertebral body.
(c) Superior mesenteric artery.
(d) Left rectus abdominis muscle.
(e) Splenic vein.
case 20
(a) Gastric fundus.
(b) Duodenal cap.
(c) Pylorus.
(d) Third part of duodenum.
(e) Duodeno-jejunal flexure.
This is part of an upper gastrointestinal contrast examination in an infant. The
position of the duodeno-jejunal flexure (and therefore the ligament of Treitz) is
crucial. It is considered normal when it meets the following two criteria: (1) it is to
the left of the spine and (2) it is superior to or at the same level as the duodenal bulb.
The emphasis of this image finding is in making the diagnosis of malrotation. This
occurs if in utero the bowel fails to rotate counterclockwise through 270 degrees,
resulting in a short base of the small bowel mesentery. This can present with midgut
volvulus, which requires urgent detection and intervention.
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