Examination 5
case 01
(a) Popliteus tendon. This point represents the popliteal groove or sulcus within
which the popliteus tendon inserts. The popliteus tendon is an important structure
that contributes to stability of the postero-lateral corner of the knee.
(b) Styloid process of the fibular head. Biceps femoris, a powerful hamstring
muscle, attaches here along with the fibular collateral ligament and the arcuate
ligament complex. The fibular styloid process can be avulsed during high energy
trauma to the postero-lateral corner of the knee producing an ‘arcuate sign’ on
radiographs.
(c) Medial collateral ligament (MCL). The MCL is an important medial stabilizer of
the knee, resisting valgus stress. A bony avulsion of the proximal MCL attachment
may produce a non-united fragment called a Pellegrini–Stieda lesion, visible on AP
radiographs.
(d) Medial tibial spine. The medial tibial spine bears the attachment of the medial
meniscal roots along with the footprint of the antero-medial bundle of the anterior
cruciate ligament.
(e) Bipartite patella. A bipartite patella is an unfused secondary ossification centre on
the supero-lateral corner of the patella. These must not be mistaken for acute fractures,
but may become symptomatic if the synchondrosis between the two bone
fragments is disrupted following direct trauma.
case 02
(a) Main submandibular duct. This is also known as Wharton's duct, and conveys
mixed mucinous and serous secretions, which are more prone to form opaque calculi.
(b) Intraglandular duct. On ultrasound scan examination, intraglandular ducts are
visualized as small linear hypoechoic stripes.
(c) Hyoid bone. This does not articulate with any other bone, and is held in position
by the thyroid ligaments. It is highly mobile, with mobility provided by a number of
muscles and ligaments. It develops from the second and third pharyngeal arches.
(d) Condylar process of the mandible. The lateral extremity of the condyle is a small
tubercle for the attachment of the temporomandibular ligament.
(e) Coronoid process of the mandible. This is a thin triangular eminence, whose
lateral surface affords insertion to the temporalis and masseter muscles.
case 03
(a) Right ischial tuberosity. The tendons of semi-membranosus, semi-tendinosus and
biceps femoris originate from the ischial tuberosity. Traumatic avulsion of the hamstring
origin may be seen in sprinting and kicking sports.
(b) Right obturator internus muscle. The obturator internus arises from the internal
surface of the obturator ring and inserts on the medial surface of the greater
trochanter. Its action is to laterally rotate the hip and abduct the thigh when the
hip is in flexion. Tumours of the rectum and ischio-rectal fossa may invade this
muscle.
(c) Symphysis pubis. This is a type II fibrocartilaginous joint between the pubic
bones. It resists pelvis rotation and anterior compression and thus may become
disrupted during pelvic trauma following these mechanisms, resulting in symphyseal
diastasis or malalignment. If missed this leads to pelvic instability and symphyseal
pain.
(d) Right rectus femoris. This is an important muscle that contributes to hip flexion
and knee extension. It arises from the anterior inferior iliac spine (AIIS) and in the
immature skeleton the AIIS apophysis may become avulsed during kicking sports
such as football. Injury of this muscle–tendon unit in adulthood usually presents with
tearing at the musculo-tendinous junction.
(e) Right sciatic nerve. This is the largest nerve in the body made up of the L4, L5, S1
and S2 roots. In the region shown in the image the sciatic nerve may undergo
entrapment by the piriformis muscle, which runs superficial to the nerve. This is
known as ‘piriformis syndrome’ and may mimic other causes of sciatic neuropathy
such as L5/S1 disc herniation, hence the alternative name of ‘pseudosciatica’.
case 04
(a) Rostrum of the corpus callosum. This is the first part of the corpus callosum which
extends from the anterior commissure.
(b) Genu of the corpus callosum. This is the most anterior part of the corpus callosum
where it bends sharply backwards. Fibres extending from the genu into the frontal
cortex are called forceps minor.
(c) Splenium of the corpus callosum. This is the thickened posterior end of the corpus
callosum. Fibres extending posteriorly from the splenium into the occipital lobes are
called forceps major.
(d) Quadrigeminal plate. This is also known as the tectum, and forms part of the
midbrain lying posterior to the cerebral aqueduct (of Sylvius).
(e) Tentorium cerebelli. This is an extension of dura mater, separating the cerebellum
fromthe inferior portion of the occipital lobes. The upper surface, in the midline, attaches
to the posterior surface of the falx cerebri and the straight sinus runs in this location.
case 05
(a) Hyoid bone. This lies at the level of C3 and consists of a body and superior and
inferior cornu.
(b) Hard palate. Three foramina open onto the oral surface of the hard palate – the
incisive fossa and the greater and lesser palatine foramina.
(c) Right mandibular condyle. The anterior projection of the ramus is called the
coronoid process.
(d) Right inferior alveolar canal. This transmits the inferior alveolar vessels and nerve
which are branches of the maxillary vessels and nerves. The proximal opening is
the mandibular foramen on the inner surface of the ramus. Distally the canal opens at
the mental foramen on the external surface of the body between the two premolars.
(e) Left maxillary sinus. The maxillary sinus opens via the ostium into the
infundibulum.
OPGs are taken by a moving x-ray source and film. The trajectory that the x-ray
source describes is that of a hemicircle behind the patient's head while the moving
film mechanism remains diametrically opposite, anterior to the patient's face.
The primary use of the OPG is to assess dentition although mandibular pathology
can also be diagnosed. Its advantage is that it allows broad coverage of the teeth and
facial bones in a short acquisition time.
case 06
(a) Gastric cardia. The gastric cardia is well seen on double contrast barium studies.
A variety of appearances may be seen, such as a filling defect, radiating folds of the
cardiac rosette and hooded fold.
(b) Pylorus. This is usually located at the L1 level to the right of the midline.
(c) Angular incisura. This demarcation along the lesser curve of the stomach separates
the body from the pylorus.
(d) Superior or first part of the duodenum. Lies antero-lateral to the L1 vertebra.
The first part (2 cm in length) has a mesentery and is mobile. This is known as the
duodenal cap.
(e) Duodeno-jejunal (DJ) flexure junction. This is situated on the left side approximately
at the level of L2 vertebra, 2–3 cm left of the midline.
case 07
sequence)
(a) Second part of duodenum (or D2). The pancreatic head has a constant relationship
with the duodenum. The right lateral border is nestled in the duodenal
sweep.
(b) Dorsal pancreatic duct (of Santorini).
(c) Superior mesenteric artery (SMA). Flow void is seen in the SMA as it courses over
the uncinate process of the pancreas. It arises 1–2 cm below the coeliac axis typically at
the level of L1.
(d) Descending colon.
(e) Pancreatic divisum. This is the most common variant of pancreatic ductal
fusion and drainage anomalies. It is caused by failure of fusion of the dorsal and
ventral buds. The short ventral duct of Wirsung drains the head and uncinate
process, with the long dorsal pancreatic duct of Santorini draining the body
and tail. It is typically seen in up to 6% of the population and up to 25% of
patients with idiopathic pancreatitis, though it is not proven to be a causative
mechanism.
Incidentally, there are two high signal cysts seen in the right kidney.
case 08
(a) Left atrium.
(b) Descending thoracic aorta.
(c) Left superior pulmonary vein.
(d) Superior vena cava.
(e) Right inferior pulmonary vein.
Normal pulmonary venous anatomy consists of a superior and inferior pulmonary
veins on each side, draining into the left atrium. It is important to remember these
carry oxygenated blood.
In addition to the normal pulmonary veins on the right, there may also be one or
two middle pulmonary veins and/or an upper pulmonary vein draining into the
superior surface of the left atrium. On the left, the superior and inferior pulmonary
veins may join to form a common trunk, either short or long. All these variant veins
drain directly into the left atrium.
At the root of the lung, the superior pulmonary vein lies anterior and inferior
to the pulmonary artery while the inferior pulmonary vein lies in the inferior
part of the lung hilum.
case 09
(a) Labrum.
(b) Femoral head.
(c) Acetabulum.
(d) Pubis.
(e) Ileum.
The beta (b) angle of the hip is the angle of the fibrocartilage to the ilium and the alpha
(a) angle is the angle of depth of the bony acetabulum. The normal angles are:
a >60degrees
b <77degrees.
These angles are important to define the presence and severity of congenital hip
dysplasia. The Graf classification indicates the degree of congenital hip
dysplasia.
case 10
(a) Right renal artery. The renal arteries arise from the aorta approximately at the
upper margin of L2. Sixty-five per cent of kidneys are supplied by a solitary vessel;
35% have an aberrant vascular supply. The right renal artery is usually longer and
passes behind the inferior vena cava.
The most sensitive and specific non-invasive screening test for renal vessel disease
is MRA (98% and 100% respectively) followed by CT (92% and 83%) and duplex
ultrasound (89% and 97%).
(b) Posterior division of the renal artery.
(c) Segmental artery.
(d) Interlobar artery. These arteries lie between the lobes (or pyramids) of the kidney.
(e) Arcuate artery. These arteries do not anastamose to form arcades, but run along
the base of the pyramids.
The branching pattern from the aorta is therefore:
Main renal artery – anterior and posterior division – segmental arteries – interlobar
arteries – arcuate arteries.
Between the anterior and posterior divisions of the renal artery is the plane of
Brodel, which is at the postero-lateral approach to the kidney. It is relatively avascular
and is the plane targeted for when performing percutaneous nephrostomy.
case 11
(a) Lunate.
(b) Capitate.
(c) Trapezoid.
(d) Scaphoid.
(e) Pisiform.
case 12
(a) Urinary bladder. Fluid is seen as high signal on T2-weighted and low signal on
T1-weighted images, unless it is haemorrhagic or proteinaceous when it will be high
on T1-weighted images. The wall of the urinary bladder should be clearly defined and
<5 mm in thickness when adequately distended.
(b) Left rectus abdominis muscle.
(c) Left femoral artery.
(d) Rectum.
(e) Right seminal vesicles. Seminal vesicles are seen as high signal on T2-weighted
and low signal on T1-weighted images. It is essential to evaluate seminal vesicles
when staging prostatic carcinoma, as disease involvement changes the staging and
usually renders the patient inoperable. Tumour involvement will change the high T2
signal to low signal. When evaluating the MRI, ensure no haemorrhage is present in
the seminal vesicles (from transrectal prostate biopsy) as this can lead to interpretation
errors.
Seminal vesicles are paired sacculated diverticula that lie transversely posterior to the
prostate and store seminal fluid. They narrow inferiorly to fuse with the vas deferens
and become the ejaculatory ducts.
case 13
aortic arch vessels
(a) Right common carotid artery. This bifurcates at C4 level. It lies in the carotid
sheath medial to the jugular vein with the vagus nerve interposed in between and
posterior to them.
Neither the common carotid or internal carotid arteries have any other branches.
The external carotid artery gives off seven branches.
Diseases of the carotid arteries are investigated using primarily Duplex ultrasound
or MRA, or usually both if there is indeterminate pathology.
(b) Right internal thoracic (or mammary) artery.
(c) Right subclavian artery. The right subclavian and carotid arteries arise from the
innominate (or brachiocephalic) artery. There is no equivalent on the contralateral
side where the two vessels have a separate origin from the aortic arch.
The subclavian artery lies in a groove in the superior surface of the first rib behind
the subclavian vein, the two being separated by the scalene muscle, which divides the
artery, into three parts. At the outer border of the first rib it becomes the axillary artery
which in turn becomes the brachial artery at the lower border of teres major.
(d) Right thyrocervical trunk.
(e) Right vertebral artery. This vessel acts as a bypass conduit in subclavian steal syndrome
where the ostium of the subclavian artery is blocked. The upper limb is then
perfused via retrograde blood flowdownthe vertebral artery from the cerebral circulation.
case 14
(a) Cornea. The most superficial structure apparent is the eyelid. The next interface
marks the thin layer of fluid over and bathing the cornea.
(b) Vitreous humour. This is contained in the posterior chamber of the eye. Between
the two chambers lie the iris, lens, suspensory ligaments and ciliary muscles.
(c) Retina.
(d) Optic disc. The layers of the globe internal to external are the retina, the choroid
and the sclera.
(e) Optic nerve. The optic nerve is normally less than 5mm in diameter, if it is greater
than this then raised intracranial pressure or an expansive lesion of the optic nerve
may be present.
Ultrasound of the eye is performed with the lid closed using an ultrasound gel
cushion to avoid unnecessary pressure on the globe. The high spatial resolution of
ultrasound makes it particularly good for assessing the globe.
case 15
(a) Anterior horn of the left lateral ventricle. The lateral ventricles are C-shaped
cavities which sit below the corpus callosum, consisting of a body, anterior and
temporal horns. They drain into the third ventricle via the interventricular foramina
of Monro (one on each side).
(b) Third ventricle. The cerebrospinal fluid (CSF) drains fromthe third to fourth ventricle
via the cerebral aqueduct (of Sylvius). The fourth ventricle empties into the central canal
of the spinal cord or the subarachnoid space via the foramen of Magendie (centrally) and
the two foramina of Lushka (laterally). CSF is absorbed from the subarachnoid space via
the arachnoid villi which project out of the superior sagittal sinus.
(c) Quadrigeminal cistern. This is one of a series of cisterns which lie within the
subarachnoid space, around the base of the brain and brainstem. Given the circle of
Willis lies within this space, a subtle subarachnoid haemorrhage may only be apparent
here, either as high attenuation within one of the cisternal spaces, effacing the
Sylvian fissure or layered posteriorly in the lateral or fourth ventricles.
(d) Right Sylvian fissure.
(e) Right temporalis muscle.
case 16
(a) Left oblique (major) fissure.
(b) Inferior vena cava.
(c) Left inferior pulmonary ligament or left pulmonary ligament. The pulmonary
ligament is present bilaterally and comprises two pleural layers that extend downwards
from the hilum of the lung between the inferior part of the mediastinal surface
of the lung and the pericardium, joining the medial lower lobe to the mediastinum
and diaphragm. It is situated inferior to the inferior pulmonary vein.
(d) Azygos vein.
(e) Right inferior accessory fissure. The right inferior accessory fissure is detected
with high resolution CT (HRCT) in approximately 20% of patients. It is seen in 8% of
PA chest radiographs and will only be detected if the x-ray beam is tangential to the
fissure. It separates the medial basal segment from the rest of the right lower lobe.
Note: the incidence of accessory fissures varies widely from study to study.
Consolidation in the medial basal segment of the right lower lobe may have a clear
demarcation line at the site of this fissure.
Other accessory fissures are:
Azygos fissure – 1–4% of PA chest radiographs (depending on study)
Superior accessory fissure – 5% of PA chest radiographs
Left minor fissure – 2% of PA chest radiographs.
case 17
(a) Arc of Riolan. This vessel lies in the mesentery and provides a connection between
the superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) via the
middle and left colic arteries at the splenic flexure. There is a more peripheral
connection of the intestinal arcades which parallel the bowel wall; in the small bowel
this is called the marginal artery of Dwight and in the colon it is called the marginal
artery of Drummond.
(b) Ascending branch of the left colic artery.
(c) Left colic artery.
(d) Sigmoid arteries.
(e) Superior haemorrhoidal (rectal) artery. The superior haemorrhoidal artery is a
continuation of the inferior mesenteric artery and branches from it communicate with
the middle haemorrhoidal (rectal) artery, which arises from the internal iliac artery
and is one of three potential collateral pathways that allow lower limb perfusion in
aortic occlusion:
1. Aorta – SMA – IMA – superior haemorrhoidals – internal pudendal artery –
internal iliac artery – external iliac artery.
2. Aorta – lumbar artery – ilio-lumbar – internal iliac – external iliac.
3. Aorta – posterior intercostal and lumbar arteries – deep circumflex iliac artery –
external iliac artery.
case 18
(a) Epiglottis. The epiglottis is a thin strip of cartilage attached inferiorly to the
thyroid cartilage. During swallowing it covers the entrance of the larynx. It is attached
on either side via pharyngeal folds to the lateral walls of the pharynx. Three anteriorly
placed glosso-epiglottic folds attach to the base of the tongue and the spaces between
the folds give rise to the valleculae.
(b) Anterior arch of cricoid cartilage. The cricoid cartilage has a ring structure anteriorly
and a flat surface posteriorly. The cricothyroid membrane joins the cricoid and
thyroid cartilages.
(c) Superior cornu of thyroid cartilage. The thyroid cartilage forms the antero-lateral
laryngeal borders. There is a notch anteriorly at C4 level known as the superior thyroid
notch. Posteriorly the laminae of the thyroid cartilage form horns – the superior cornu,
which joins with the posterior hyoid bone via the triticeal cartilage in the lateral thyrohyoid
ligament, and the inferior cornu, which articulates with the cricoid cartilage.
(d) Anterior tubercle of transverse process of C5.
(e) Thyroid cartilage.
case 19
(a) Right ventricle.
(b) Pulmonary trunk.
(c) Left inferior pulmonary vein.
(d) Left superior pulmonary vein.
(e) Left main bronchus. The left main bronchus has a more horizontal course than the
right main bronchus. Consequently the left main bronchus is ovoid on lateral chest
radiographs and sagittal CT images, unlike the right main bronchus, which is tubular
and more ‘vertical’.
case 20
(a) Left parotid gland. This is the largest salivary gland and is divided into deep and
superficial lobes which are connected around the posterior surface of the mandible by
the isthmus. Its duct (Stensen's duct) opens into the buccal cavity opposite the upper
second molar tooth.
(b) Left masseter muscle. This muscle lies in the masseteric space with the pterygoid
muscles. It has deep and superficial components and is innervated by a branch of the
mandibular nerve (trigeminal nerve III). The space is an important tissue compartment
in the face and can be the site of abscess formation. It is often difficult to
diagnose pathology here.
(c) Left pterygoid muscles. The medial pterygoid muscle extends from the pterygoid
plates medially to the inner surface of the mandibular condyle laterally. The medial
pterygoid inserts with the masseter by a common tendinous sling onto the medial
surface of the ramus and angle of the mandible. It thus contributes to elevation of the
jaw. The lateral pterygoid muscle arises from the greater wing of the sphenoid bone,
and the lateral surface of the lateral pterygoid plate. It inserts onto the mandibular
condyle with its superior head attaching onto the articular disc and fibrous capsule of
the temporomandibular joint. It acts by lowering the mandible and so opens the jaw.
Unilateral action of a lateral pterygoid produces contralateral excursion and so
contributes to chewing.
(d) Left lateral wall of the pharynx. Lateral to this lies fat in the left parapharyngeal
space which is seen as high signal on this T1-weighted image.
(e) Right ramus of the mandible. The fatty marrow appears bright and the cortex dark
on this T1-weighted image.
Comments
Post a Comment