7. Split Fat sign
Thin peripheral rim of fat best seen
on planes along long axis of the
lesion in non fat suppressed
sequences
Peripheral nerve
sheath tumors.
21. #Differentials
SNAC
Complication of Non united
scaphoid fracture
Radioscaphoid osteoarthritis.
Then proximal capitate migration.
SLAC
Complication of
scaphoLunate dissociation
Radioscaphoid osteoarthritis.
Then proximal capitate migration.
25. Treatment of SNAC / SLAC
Four-corner fusion arthrodesis.
- Partial fusion technique.
- Used in advanced degenerative changes
- To reduce pain.
Scaphoidectomy and four corner fusion.
27. #Differentials (Pain and soft tissue edema)
CRPS
Diffuse patchy
("bone marrow edema") on STIR images.
- BME fluctuate or migrate to other areas.
- Soft tissue edema.
Acute Charcot
Focal distribution
bone marrow edema of the mid foot.
- BME Regress steadily.
- Soft tissue edema.
28. Charcot/ Neuropathic arthropathy
Acute
- Mid foot-
marrow edema.
Chronic
- No bone marrow
edema.
- Rocker bottom
deformity.
Chronic with
superimposed
OM
- Ulcer (arrow).
- Edema in cuboid/
near the ulcer.
29. Chronic Charcot
Malalignment of the mid foot intertarsal
articulations with consequent collapse of
the navicular bone.
Obliteration mounting to Reversal of the
longitudinal plantar arch creating
pressure point at the mid foot level.
30. Chronic Charcot with superimposed
osteomyelitis.
Focal skin interruption/ ulcer
(arrow) along the level of the
bony protuberance of the
cuboid.
36. Stage I :-
Negative
Stage II :-
Mixed subchondral
sclerosis and cysts. Stage III :-
Femoral head
collapse.
Stage IV :-
Collapse and OA.
Classification of AVN
40. Osteofibrous
dysplasia
- Young age (10 y)
- Size: 7 cm
- Bubbly
appearance.
- Ground glass on
CT.
Adamantinoma
- Older age/ 2nd -
3rd decade.
- Size: 10-17 cm
- Lytic areas
interspersed with
areas of sclerosis.
- Destruction/
locally malignant
# Differentials
Both has eccentric epicenter
41. Osteofibrous
dysplasia
- Young age (10 y)
- Lesion begins in
anterior cortex.
- Anterior bowing of
tibia.
Fibrous dysplasia
- Older age/ 2nd -
3rd decade.
- No osteoblastic
rim.
- Endosteal
scalloping.
# Differentials
48. *** Fractures will be within
zone of vulnerability:-
o Radial styloid,
o Waist of the scaphoid or
capitate,
o Proximal pole of the
hamate, triquetrum or ulnar
styloid.
Line of Osseous injury
54. Epimysial injury (peripheral injury)
The epimysium is the fibrous tissue/
fascia that lies at the edge of the muscle.
With epimysial injury, fluid tends to leak
out and collect in perifacial space-------
Epimysial pattern of edema.
55. Wrisberg rib
- Characteristic longitudinal
tear of the posterior horn of
the lateral meniscus.
- The most common mensical
injury with ACL tear.
- May be used as a secondary
sign of ACL disruption.
Wrisberg ligament
56. Mechanism of injury
- Ligament of Wrisberg (small arrow
heads) coursing from the medial
femoral condyle to the posterior horn
laterally.
- So anterior tibial translation creates
meniscal injury passing through root
into the PHLL (Red arrow) at the site of
the Wrisberg attachment.
64. PLC injury
Avulsion of distal biceps
femoris tendon from
fibular head
Proximal tear of fibular
collateral ligament
Popliteus injury Torn
popliteofibular
ligament
67. Talonavicular coverage angle
With pes cavus , there is medial peritalar subluxation
of the navicular
Normally navicular bone ends with the same edge of
talus.
69. Tibial tubercle to trochlear groove
distance (TT-TG distance).
- Used to assess patellar translation /
patellar instability .
- Performed by superimposing axial
images of the femoral condyles
and tibial tuberosity.
70. Draw a line along the posterior femoral condyles, and then draw the following lines
perpendicular to this line:
Bisecting the tibial tuberosity (TT)
—Bisecting the trochlear groove sulcus (TG)
žMeasure the distance between TT and TG = TT-TG distance.
Normal distance <15 mm .
71. Assessment of hindfoot abnormality
on plain X-ray
Angle between the tibial shaft axis and the
calcaneal axis (adapted line to the medial
and lateral surfaces of the calcaneus).
72. Clubfoot
Clubfoot, or talipes equinovarus, is a congenital deformity consisting of
hindfoot equinus, hindfoot varus, and forefoot varus.
73. Hindfoot deformities
Talocalcaneal angle. (AP view)
Formed between the long axis of the talus and a line
drawn along the lateral surface of the calcaneus,
Note that the long axis of talus normally extends along
the first metatarsal, and the central long axis of
calcaneus normally extends along the fourth metatarsal.
74. Talocalcaneal angle (AP view)
- If < 20 degrees then varus deformity
- If > 40 degrees then valgus deformity
75. Talocalcaneal angle (Lateral view)
angle formed between the longitudinal axes of the
talus and calcaneus
if < 35 degrees then varus deformity >>>>
clubfoot, pes cavus foot.
if > 50 degrees then valgus deformity congenital
vertical talus, flatfoot
76. - The midline of the calcaneal
tuberosity (arrow) normally lies
slightly lateral to the mid-
diaphyseal axis of the tibia,
giving a normal hindfoot angle
of 0 to 5 degrees valgus.
78. Calcaneal pitch
Angle formed by a line from the base of heel &
inferior cortex of calcaneus.
if < 20 degrees then pes planus/ flat foot.
if > 25 degrees then pes alta
79. Normal talar - 1st metatarsal (Meary's
angle).
Standing lateral X ray.
Normal -0, straight line
82. Achilles tendon tear
Insertional
Non insertional 2-6 cm away from insertion (hypovascular area).
Complete/ full thickness.
Partial thickness.
Torn fibers; overlapped, gab, retraction.
83. Tibialis posterior dysfunction
Torn tibialis posterior tendon-----------> flat foot.
As tendon has slips going to all tarsal bones.
84. Tibialis posterior dysfunction
It occurs when the posterior tibial tendon becomes
inflamed or torn
There is Significant link between PTTD and the
stabilization of plantar arch, like the spring ligament
plantar fascia and tarsal sinus ligaments injuries.
Hindfoot valgus
89. Flat foot
The red lines show the
impaired longitudinal axes
of the talus and the first
metatarsal bone.
90. FHL tenosynovitis
(sites) behind talus between medial and
lateral tubercle,
behind sustantaculum tali,
and at the tendon intersection (MKH)
between the sesamoid bone of the big
toe,
92. Master knot of Henry
- The crossing of the flexor
digitorum longus tendon
obliquely over the flexor hallucis
longus tendon in the midfoot, at
the level of the navicular bone
- One of the locations of flexor
hallucis longus tenosynovitis
99. Spring ligament
Spring ligament/ superomedial
portion (comes off
sustentaculum tali to hug the
head of talus)
Medioplantar oblique (Heads) …. MPO
Inferoplantar longitudinal (arrow)… IPL
104. Change in the orientation of the middle facet (shd be transverse) if sloping
downward laterally = coalition… DUE TO change in orientation of bone with body
weight.
106. "Penumbra Sign“
Osteomyelitis
‘’ Rim of granulation tissue eliciting high signal in T1 relative to the cavity and isointense signal relative to the
muscles’’
118. - The foot can be divided into
three anatomical sections called
the hindfoot, midfoot, and
forefoot.
- The hindfoot consists of the
talus and the calcaneus.
Lateral hindfoot impingement
( Extraarticular lateral ankle impingement).
119. It can be divided into:-
o Talocalcaneal impingement.
o Subfibular impingement.
o Combined talocalcaneal-
subfibular impingements.
Lateral hindfoot impingement
121. Chronic hindfoot valgus malalignment
which is often due to
posterior tibial tendon
insufficiency
‘’ tendon crucial in
maintaining the
longitudinal arch of the
foot’’
122. Measured by angle
between the medial
calcaneal cortex and the
long axis of the tibia just
posterior to the
sustentaculum tali.
Hindfoot valgus measurement
139. #Differentials
CPPD arthropathy
- Bilateral
- Arthropathic changes mainly at the radiocarpal
joint.
- Scapholunate separation.
- Calcifications at TFCC. (chondrocalcinosis)
SLAC
- Unilateral/ post traumatic.
- Arthropathic changes mainly at the
radiocarpal joint.
- Scapholunate separation.
- No calcifications at TFCC.
140. #Differentials
(Arthropathy at DIP)
Hyperpara-
thyroidism
- Whiskering &
- Erosions at radial side
of middle phalanx.
Psoriasis
-Ill defined
osteophytes/
Whiskering.
- Central collapse
Erosive OA
- Sharp osteophytes.
- Central joint
collapse.
Gout
- Eccentric erosions,
Overhanging edge.
- Juxta articular Soft
tissue mass/ tophus.
141. Carpal boss
Degenerative
•Degenerative osteophyte formation
Os styloideum
Accessory ossicle of the wrist.
Hypertrophied bony protuberance at the base of the second or third metacarpals on the dorsal surface.
142. Pronator fat pad sign.
Ventral bulging of the fat pad overlying the
pronator quadratus muscle (PQM).
= Radial fracture
143. Tear drop sign
Ankle joint effusion.
Teardrop shaped opacity at the inferior part of the
anterior compartment of the ankle.
144. Knee joint effusion
Well-defined homogeneous soft tissue density
within the suprapatellar recess and Hoffa’s fat pad
on a lateral radiograph.
145. Fat pads in the knee:-
Suprapatellar and prefemoral fat pads.
Soft tissue density in-between the two
fat pads, indicates effusion.
- Simple effusion (haemarthrosis):- think
of sever ligamentous, mensical or intra-
articular bone injury.
- Fat fluid level (lipohaemarthrosis):-
think of intra-articular fracture.
149. Soft tissue lesions with fluid/ fluid levels.
Cavernous
haemangioma
(>2/3rd of the lesion)
Synovial
sarcoma MPNST.
(of the right intercostal
space)
(Fl/Fl level <
2/3rd of the
lesion due to
necrosis) =
high grade
sarcomas
150. Bone lesions with fluid/ fluid levels.
ABC Telangiectatic
osteosarcoma GCT with
secondary ABC
157. Soft tissue lesions
Group I
High SI T1 and intermediate T2 (relative to bone marrow) Lipoma, melanoma
(rare).
Group II
Intermediate SI T1 and high T2 haematoma, haemangioma, synovial
sarcoma.
Group III
Low SI T1 and high T2 ganglion, myxoma, myoid liposarcoma.
myxofibrosarcoma.
Group IV
Low to Intermediate SI T1 and low T2 Desmoid, PVNS.
158. - Fat signal with
fine internal
septations.
Lipoma
• Old
• - Intralesional
dark signal soft
tissue masses in
T1 WIs. (Asterix).
Liposarcoma
Children.
- Intralesional
dark signal soft
tissue masses in T1
WIs.
Lipoblastoma
Group I
168. Target sign
Malignant peripheral nerve
sheath tumor
Low signal intensity centrally and high signal intensity peripherally on T2 weighted sequences
171. Athletic pubalgia
Superior cleft sign
Hyperintense area along
the superior pubic ramus
= Rectus
abdominus/adductor
longus attachment
microtear.
Secondary cleft
sign
Hyperintense area along
the inferior pubic ramus
= Short adductor
attachment microtear.
Osteitis
pubis
173. Shoulder labrum variations
(a) Normal anatomy; (b) Sublabral recess (sublabral sulcus); (c) Sublabral foramen (sublabral
hole); (d) Buford complex. LHBT: long head of biceps tendon, SGHL: superior glenohumeral
ligament, MGHL: middle glenohumeral ligament, IGHL: inferior glenohumeral ligament.
174. Sublabral recess
an increased linear signal undercutting the contour of the superior glenoid labrum (arrows,A)
following the contour of the glenoid cartilage without extension posterior to the biceps
anchor.
175. Sublabral Foramen
It is located between the one o’clock and three o’clock position and provides a communication between the glenohumeral
joint and the subscapularis recess (white arrows).
Normal appearing anterior superior labrum (arrowheads), and middle glenohumeral ligament (black arrows)
176. Buford complex
A cord-like middle glenohumeral ligament (white arrow) associated with an absent anterior superior labrum (black arrow)
mimicking a labral tear with normal posterior labrum. Subscapularis tendon (arrowhead).
177. #Differentials Elbow Joint
Osteochondral injury
Following repeated stress injury.
Lies along the anterior aspect of
capitellum.
Posterior capitellar impaction
Following posterior elbow dislocation.
Lies along the posterior aspect.
178. Muscle edema
Strain/contusion
Following trauma
Muscle edema (e.g:-
feathery appearance).
Myositis
Non traumatic
changes
Muscle and fascial
edema.
Denervation.
(Early phase)
Nerve affection
e.g:- Enlarged cervical
roots --->