Examination 7
case 01
(a) Posterior column of the left acetabulum. The posterior and anterior columns of
acetabulum provide the dominant load-bearing support of the hip joint. It is important
to evaluate the integrity of the acetabular columns in the setting of pelvic trauma
as fracture involvement of these structures is integral to all classification systems of
acetabular fractures.
(b) Left rectus abdominis muscle. This is a strap-like muscle encased in a fascial
sheath. It inserts onto the anterior surface of the pubic symphysis and has an
aponeurosis which is continuous with that of the gracilis and adductor longus
muscles.
(c) Right obturator internus. This arises from the internal surface of the medial
acetabulum and inserts on the greater trochanter of the femur. Its action is to produce
external rotation of the hip.
(d) Right sartorius muscle. This arises from the anterior superior iliac spine. It has a
long muscle belly directed distally and medially spanning the hip and knee joints with
an insertion on the antero-medial aspect of the tibia as one of the pes anseurinus
tendon group.
(e) Greater trochanter of the left femur.
case 02
(a) T11/T12 disc space.
(b) T12 vertebral body.
(c) Twelfth rib.
(d) L1 pedicle.
(e) L1/L2 facet joint.
The interpedicular distance should increase to a maximum at the L5 level.
Pedicular destruction is most common in metastatic disease.
Irregularity of the endplates with loss of disc height is often seen in discitis.
Less than 10 degrees of scoliosis is within normal limits.
The lateral film demonstrates the depth of the posterior costophrenic angle with the
lungs reaching the T12 level.
case 03
(a) Frontal sinus.
(b) Sphenoid sinus.
(c) Pituitary fossa.
(d) Internal occipital protuberance.
(e) Posterior arch of C2.
Skull radiographs are no longer performed in trauma cases due to the poor sensitivity
for intracerebral injury and the widespread availability of CT scans.
case 04
(a) Air in the left piriform fossa. This is part of the hypopharynx.
(b) Left internal jugular vein. The anterior branch of the retromandibular vein joins
the facial vein to form the internal jugular vein.
(c) Right sternocleidomastoid muscle. The superior attachment is the mastoid process
of the temporal bone. The inferior attachments are to the manubrium and the
clavicle.
(d) Air in the supraglottic larynx. The supraglottic larynx consists of the false cords
and aryepiglottic folds.
(e) Left internal carotid artery. This gives off two small branches in the petrous
region – the caroticotympanic artery to the ear drum and the pterygoid artery to the
pterygoid canal and plate. There are further small branches which come off in the
cavernous region.
case 05
hepatis
(a) Left lobe of the liver. The liver is typically a homogeneous mid-grey organ with
echogenicity slightly increased when compared to cortex of right kidney.
(b) Hepatic artery. Generally crosses the anterior aspect of the portal vein with the
common duct anterior to this. A common variant is the artery lying anterior to the
common duct.
(c) Portal vein. This enters the liver and is encased by hyperechoic, fibrous walls of
the portal tracts.
(d) Common bile duct. This is best seen with the patient supine in a right anterior
oblique position. Typically measures approximately 6 mm or less. However, it is age
dependent and can be 8–9 mm in the elderly.
(e) Inferior vena cava (IVC). The three hepatic veins drain into the IVC just inferior to
the diaphragm. The attachment helps hold the liver in position. The IVC runs posteriorly
to the liver before passing through the caval opening in the diaphragm at T8
level.
case 06
(a) Junctional zone of uterus.
(b) Endometrial cavity.
(c) Urinary bladder.
(d) External os of uterus.
(e) Myometrium of uterus.
Ultrasound, both transabdominal and transvaginal, and MRI are used to assess the
female pelvis. MRI has superior soft tissue contrast, and can delineate anatomy
very clearly. On T2 sequences the endometrium, endocervical canal and vaginal
canal are of high signal. The inner zone of the myometrium is of low signal and
known as the junctional zone. This is histologically similar to the remainder of the
myometrium. The outer myometrium is of intermediate signal. There is high signal
pelvic fluid.
T1-weighted images of the uterus and ovaries show intermediate signal with poor
contrast.
Fibroids (leiomyoma) are the most common tumour of the uterus, found in 25% of
females >35 years. They arise from smooth muscle cells and can be well visualized on
MRI. They are typically seen as low signal lesions relative to the remainder of the
uterus on T2-weighted images and isointense to the uterus on T1-weighted images.
case 07
(a) Left head (condyle) of mandible.
(b) Foramen magnum. With raised intracranial pressure from any aetiology (traumatic,
neoplastic, ischaemic) the cerebellar tonsils can descend through the foramen
magnum which is known as tonsillar herniation. This causes compression of the
cardiac and respiratory centres within the brainstem and thereby death. This is best
appreciated on sagittal MR though can be suspected on CT. Other possible brain
herniations include:
1. transtentorial (or uncal) herniation where the medial aspect of the temporal
lobe (uncus) herniates inferior to the tentorium cerebelli
2. subfalcine herniation where a frontal lobe crosses the midline and passes
beneath the falx cerebri (midline shift).
(c) Right carotid canal. Part of the petrous apex of the temporal bone.
(d) Sphenoid sinus. There are varying degrees of pneumatization of the sphenoid
sinus in individuals. The sphenoid sinuses drain into the sphenoethmoidal recesses,
either side of the nasal septum.
(e) Right optic nerve.
case 8
(a) Second part of duodenum.
(b) Common bile duct (CBD).
(c) Superior mesenteric artery.
(d) Left internal oblique muscle.
(e) Pancreas divisum. This anomaly is present in up to 14% of the population (in
autopsy series). Normally the shorter ventral duct (Wirsung), which drains the head
of the pancreas, joins the CBD (labelled B) to drain via the major papilla into the
duodenum. There is failure of fusion of the ventral duct with the main dorsal
pancreatic duct (Santorini), which drain the body of the pancreas. The dorsal duct
drains into the duodenum via the minor papilla. There is an unproven suggestion that
this anomaly predisposes to pancreatitis.
case 9
(a) Left lobe of the liver.
(b) Interventricular septum (IVS). This is composed of muscular and membranous
parts. Due to the high blood pressure in the left ventricle the muscular part of the IVS
forms the majority of the septum.
(c) Left ventricle. This forms the apex and nearly all the left surface of the heart.
(d) Right ventricle. This forms the majority of the anterior surface of the heart.
(e) Left atrium. This forms most of the base of the heart. Four pulmonary veins enter
its smooth posterior wall.
case 10
(a) Left temporal lobe.
(b) Interpedicular cistern.
(c) Quadrigeminal cistern.
(d) Left cerebral peduncle.
(e) Right middle cerebral artery (MCA). The arrow points at the horizontal or M1
segment of the MCA. This gives off a number of lenticulostriate arteries which perfuse the lateral basal ganglia. At the insula, the artery turns into the Sylvian fissure (M2
segment) giving off a number of insular branches. The branches emerge form
the lateral aspect of the Sylvian fissure extending anteriorly and posteriorly over the
frontal, parietal and temporal lobes (M3 segment).
In acute stroke thrombus can be seen within the MCA. On CT, this is called the
hyperdense MCA sign if the thrombus is in the M1 segment, and if it is in the M2
segment as the hyperdense MCA dot sign.
case 11
(a) Minor or horizontal fissure.
(b) Right middle lobe.
(c) Anterior junction line.
(d) Posterior wall of bronchus intermedius.
(e) Left lower lobe pulmonary artery.
HRCT has sufficient resolution to depict the fissures as thin lines. On conventional
non-thin slice CT, low attenuation areas of avascularity represent the fissures.
The horizontal fissure on axial slices encircles the right middle lobe. This is because
the horizontal fissure is convex superiorly.
case 12
(a) Companion shadow of left clavicle.
(b) Azygos vein.
(c) Right hilar point.
(d) Right interlobar pulmonary artery.
(e) Bronchus intermedius. The pulmonary arteries are always located alongside
bronchi. In the case of bronchus intermedius, it lies adjacent to the interlobar artery.
case 13
(a) Lamina dura. This is a dense white line of bone surrounding the root of each tooth.
(b) Periodontal ligament. This is the radiolucent line around the neck and root of the
tooth.
(c) Pulp chamber. The pulp canals extend inferiorly from this and transmit nerves
and vessels from the supporting bone.
(d) Dentine.
(e) Enamel. This is the densest material in the body.
case 14
(a) Right psoas muscle. (Right side because the aortic root can be seen. Plus see
answer (e).)
(b) Inferior vena cava.
(c) Left atrium.
(d) Oesophagus.
(e) Aberrant right subclavian artery. The aberrant right subclavian artery arises from
the aorta distal to the left subclavian artery, traverses behind the oesophagus to
supply the right arm. It will produce a posterior impression on the oesophagus at
barium swallow.
case 15
(a) Coracoid process of the right scapula.
(b) Right transverse process of T3.
(c) Spine of left scapula.
(d) Aorto-pulmonary window.
(e) Right cervical rib. A cervical rib articulates with a transverse process which is
orientated in a downwards direction unlike thoracic ribs, which articulate with
an upwardly orientated transverse process. They may cause vascular and neural
compression leading to symptoms in the upper limb.
case 16
(a) Falx cerebri.
(b) Left corona radiata.
(c) Posterior horn of the left lateral ventricle.
(d) Left parietal bone.
(e) Cavum vergae. This is a normal variant similar to cavum septum pellucidum
except in this case the separation of the septum pellucidum leaflets extends back to the
splenium of the corpus callosum.
case 17
(a) Left intercostal artery.
(b) Left intercostal vein.
(c) Left erector spinae muscle.
(d) Left costotransverse joint.
(e) Left infraspinatus muscle.
The intercostal neurovascular bundle is exposed posteriorly and has no protection
from the bony intercostal groove. This is very different to the situation that exists in
the antero-lateral chest wall where the neurovascular bundle is protected by the
subcostal groove. The neurovascular bundle is situated between the internal and
innermost intercostal muscles. The lack of protection posteriorly makes chest drain
insertion and percutaneous intrathoracic biopsy procedures particularly hazardous
with resulting haemothoraces as the most serious complication if there is arterial
puncture. Therefore, great care must be taken when accessing the thorax via a
posterior approach. Avoidance of this route is preferable but if access must be made
at this site, a caudal tilt to the needle so that it glances the superior aspect of the rib
below is advisable in order to reduce the risk of arterial puncture.
case 18
(a) Ligamentum flavum.
(b) Basivertebral vein.
(c) Interspinous ligament.
(d) Nucleus pulposus of L2/L3 disc
(e) Annulus fibrosis of L4/L5 disc.
case 19
(a) Acromion.
(b) Clavicle.
(c) Coracoid process.
(d) Glenoid.
(e) Lateral scapular border.
case 20
(a) Anterior aortic cusp (or sinus of Valsalva). The right coronary artery arises from
here. The left coronary artery arises from the left posterior sinus.
(b) Right subclavian artery.
(c) Aortic arch. The aortic arch is defined as the aorta from the right brachiocephalic
artery to the attachment of the ligamentum arteriosum. It can be further subdivided
into proximal arch (right brachiocephalic artery to left subclavian artery (LSA)) and
distal (LSA to attachment of ligament arteriosum). The distal arch is sometimes
referred to as the isthmus or ‘bridge’ and may be narrower than the proximal
descending aorta. The isthmus represents the weakest part of the arch and is prone
to transection, intimal laceration and false aneurysm formation in decelerating road
traffic accidents.
(d) Left axillary artery.
(e) Ductus diverticulum (‘ductus bump’). This is a fusiform dilatation along the
ventro-medial aspect of the descending aorta adjacent to the ligamentum arteriosum.
It is present in up to 9% of adults. Its appearances are sometimes confounding in blunt
trauma as it can be confused with a false aneurysm. This point on the aorta is a
transition between the fixed descending aorta and mobile aortic arch, and therefore
represents a site where transection and focal aneurysm can occur.
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