Scan plane for the extensor
digitorum tendon of the foot.
Extensor digitorum tendon. There is a common
tendon until the level of the extensor retinaculum
at the anterior ankle crease. After this, the tendon
divides to the 4 lateral toes. (The big toe has it's
own tendon - the extensor hallucis).
Tibialis Posterior tendon
Flexor Digitorum tendon
Flexor Hallucis Longus tendon
Posterior tibial nerve
Scan plane to see Tibialis Posterior, Flexor
Digitorum and Flexor Hallucis Longus (you
may need to adjust the probe posteriorly
to view the deeper FHL).
Tibialis posterior, flexor Digitorum and flexor
Hallucis longus tendons (known as "Tom, Dick
& Harry"). If including the neurovascular
bundle - Tom Dick And Very Nervous Harry.
Deltoid Ligament scan plane: Use
plenty of gel and have the probe
tip overlie the malleolar tip.
Because of it's obliquity, you cannot
readily see all aspects of the ligament.
Retrocalcaneal (Kager's) fat-pad
Scan plane for the Achilles tendon. Normal Achilles tendon longitudinal panorama.
ULTRASOUND OF THE ANKLE PROTOCOL
ROLE OF ULTRASOUND
Ultrasound is essentially used for the external structures of the ankle. Ultrasound
is a valuable diagnostic tool in assessing the following indications; Muscular,
tendinous and ligamentous damage (chronic and acute) Bursitis Joint effusion
Vascular pathology Haematomas Soft tissue masses such as ganglia, lipomas
Classification of a mass e.g. solid, cystic, mixed Post surgical complications e.g
abscess, edema Guidance of injection, aspiration or biopsy Relationship of normal
anatomy and pathology to each other Some bony pathology.
It is recognised that ultrasound cannot adequately assess the deltoid ligament,
the ankle mortice and some inter-tarsal ligaments.
EQUIPMENT SELECTION AND TECHNIQUE
Use of a high resolution, (8-15MHZ)small footprint probe , is essential when
assessing the superficial structures of the ankle. Careful scanning technique to
avoid anisotropy (and possible misdiagnosis) Beam steering or compounding can
help to overcome anisotropy in linear structures such as tendons. Good colour /
power / Doppler capabilities when assessing vessels or vascularity of a structure.
Be prepared to change frequency output of probe (or probes) to adequately assess
both superficial and deeper structures.
Patient sits on the side of a raised bed with foot resting on the Sonographers knee for
support. Alternatively, the patient may sit or lie supine on bed with their foot flat.
Peroneus longus and brevis tendons: Begin in transverse, posterior to the lateral malleolus.
The two tendons are easily seen with the peroneus brevis closest to the bone. Follow them
proximally to the muscle and distally with particular attention to the insertion of the
peroneus brevis tendon onto the base of the 5th metatarsal.
Calcaneo-fibular ligament: With the probe diagonally under the malleolus, angled from the
fibula to the heel, you will see the peroneus tendons in transverse and the calcaneo-fibula
ligament underlying them.
Patient positioned as above.
Anterior talo-fibula ligament (ATFL): Place the heel of the probe on the anterior aspect of
the distal fibula and rotate the toe of the probe towards the 2nd toe. The ligament should
be readily visible as a 2cm long, 3mm thick tight fibrillar structure.
Tibio-Fibula ligament (TFL): From the ATAF, further rotate the toe of the probe until just
above the horizontal. The TFL has a similar appearance to the ATAF.
Extensor tendons: In transverse across the anterior ankle crease, you will see, from lateral
to medial, the extensor digitorum, extensor hallucis and tibialis anterior tendons. By
independently mobilizing each of the toes and watching the tendons glide, you can identify
which is which and exclude tendon rupture The overlying extensor retinaculum should also
Patient positioned as above.
Tibialis posterior, flexor digitorum and flexor hallucis longus tendons: Assess the
tendons along their length in longitudinal and transverse. Pay particular
attention to the insertion of the Tibialis Posterior tendon with caution not to
mistake the often present accessory ossicle, for an avulsed fragment. Begin
diagonally under the medial malleolus with the toe of the probe on the malleolus.
You will see the tibialis posterior and flexor digitorum tendons in transverse. Slide
the probe postero-inferiorly and you will see the flexor hallucis longus tendon
deeper against the calcaneum.
The deltoid ligament: Is poorly assessed with ultrasound.
Posterior tibial nerve: The neurovascular bundle is easily seen posterior to the
Patient positioned prone with the feet off the end of the bed.
Achilles tendon: Perform a survey scan ,in transverse, from the calcaneum up to
the musculo-tendinous junction (of both medial and lateral gastrocnemii). Rotate
into longitudinal and examine for thickening and integrity. At the same time
assess the retrocalcaneal (Kager's) fat pad.
The calf muscles and plantaris tendon should also be assessed as clinically
An ankle series should include the following minimum images;
Peroneus tendons - long, trans + peroneus brevis insertion
Anterior talo-fibula ligament
Extensor digitorum tendon
Extensor hallucis longus tendon
Tibialis anterior tendon
Tibialis posterior tendon
Flexor digitorum tendon
Flexor hallucis longus
Achilles tendon and retro calcaneal bursa
Document the normal anatomy. Any pathology found in 2
planes(ligament tears or thickening, synovial bulging/cysts, joint
effusion, gross bony changes), including measurements and any
MAIN INDICATIONS OFTHE ANKLE ULTRASONOGRAPHIC STUDY
Tendon pathology of the different compartments
of the ankle.
• Evaluation of ligament injuries.
• Bone and joint disorders (synovitis, chondral
and osteochondral lesions, occult fractures)
• Retroachilles and preachilles bursitis.
• Characterization of tumors (accessory muscles, ganglia,
neurogenic tumours, soft tissue abscesses, etc.)
• Localization of foreign bodies.
ABNORMALITIES OF TENDONS
Tendon injuries include tenosynovitis, tendinosis,
rupture and instability.
Can be classified as tendinosis and paratendinitis. The isolated
paratendinitis shows intratendinous normal structure, exist paratendinitis
spill, shown irregularities in the edges of the tendon, adhesions and
scarring associated paratendon and a heterogeneous aspect preachilles
fat pad. In the tendinosis there is in swelling of the tendon, usually
bilateral, and textural heterogeneity intratendinous focal hypoechoic areas.
TEAR OF ACHILLES
The rupture site is located generally between the 2 and 6 cm from the insertion
into the calcaneous, in the called critical zone of relative hypovascularity.
In ultrasound, complete rupture of the Achilles tendon is seen as a focal defect
between the broken ends of the tendon. In the acute phase ends are
contiguous, but the defect may be filled by the anechoic or hypoechoic
hematoma. In most cases paratendon remains intact as a envelope straight
echogenic contouring breakage. As a sign associated can exist distortion of the
fibrillar configuration and loss of parallelism of the tendon fibers. Other signs
are indicative fat herniation into the defect, better visualization of the plantar
tendon and the existence of a posterior acoustic shadowing at the site of the
tear (useful sign to differentiate partial thickness tears).
Complete rupture of the Achilles tendon with focal defect between
the ends of the tendon and posterior acoustic shadowing at the
site of the tear, useful sign to differentiate partial thickness tears.
Patient with psoriasis which identifies tendinosis and Achilles tendon swelling
bilateral and textural heterogeneity with intratendinous focal hypoechoic areas.
Ultrasound and radiological correlation calcified Achilles
enthesitis. Calcaneal spur as associated finding.
Discreetly thickened right Achilles tendon at its insertion, combining linear hyperechoic
and hypoechoic areas on small breaks intrasubstance and calcifications of the enthesis.
Fat herniation into the defect by complete tear of the Achilles tendon.
Complete tear of the Achilles tendon with retraction
of ends and integrity thin plantaris tendon.
Tendinosis versus partial tear of Achilles tendon.
•PREACHILLES AND RETROACHILLES BURSITIS
Although bursitis can occur in isolation, often are
related and systemic inflammatory diseases.
In the ultrasound examination the distended
retrocalcaneal and preachilles appears are a
hypoechoic structure shaped coma, interposed
between the Achilles tendon and the posterosuperior
aspect of the calcaneous. Care must be taken not to
confuse it with the fatty space Kager containing oval
lobules of hyperechoic fat. When bursitis is a
manifestation of synovitis is appreciated
hypervascular area with Doppler ultrasound.
In the retroachilles bursitis exists thickening and
collection of fluid in the subcutaneous tissue
superficial to the tendon retrocalcaneal portion.
Bursitis preachilles with typical morphology, appreciating accumulation of fluid
in a "coma" between the anterior portion of the Achilles tendon and the calcaneous.
Bursitis preachílea that associated synovitis, showing hyperemia with increased Doppler flow.
Rheumatoid arthritis with retrocalcaneal bursitis (*1) and calcaneal erosions (*2)
ACCESSORY NAVICULAR BONE
In the distal insertion site may exist TP 2 types of bones
Accessory navicular bone type I (os tibiale externum): size
between the 2 and 6 mm, can be contained within the TP and
being positioned immediately proximal posteromedial to the
navicular bone. It generally produces symptoms and should
not be confused with a tendon calcification or avulsion
Type II accessory navicular bone: is an accessory
ossification centre of the navicular bone with size between
9 and 12 mm triangular shaped and articulated through a
synchondrosis of the posterior and medial navicular bone.
It insertion site of some fibers of TP and is associated with a
syndrome of pain and increased incidence of tendon rupture
caused by abnormal overloads. Osteoarthritic changes may
underlie this synchondrosis which mimic tendon pathology.
Accessory navicular bone within the posterior tibial tendon, as anatomical variant.
The tendons of the anterior ankle, compared
with the rest of the ankle tendons are rarely
affected by disease. The anterior tibial tendon
is the most prone to abnormalities, like
tendinopathy, tenosynovitis and its place
between the most frequent rupture is extensor
retinaculum and insertion into the first
cuneiform and the base of the first metatarsal.
Sometimes the retracted tendon stump causes
a nodule on the anteromedial aspect of the
distal portion of the leg, making clinically
confused with a tumour or cyst.
Distal insertion tendinopathy of the anterior tibial tendon with increased vascularity
Tenosynovitis of the anterior tibial tendon with effusion.
Anterior tibial tendon tenosynovitis with intratendinous ruptures.
Anterior tibial tendon rupture with retraction of the tendon.
Tenosynovitis of the extensor digitorum tendons with a synovial effusion.
Tenosynovitis of the extensor digitorum tendon with
hypervascularized thickened tendon and synovium and synovial fluid.
Rheumatoid arthritis with tenosynovitis of the extensor digitorum and peroneal tendons.
Thickening of the extensor hallucis longus tendon caused by osteosynthesis material.
Multicystic non vascularized intramuscular mass in the extensor digitorum brevis muscle.
TENOSYNOVITIS OF THE PERONEAL TENDONS
The main sign of ultrasound is the presence of liquid inside the
common synovial sheath, whereas usually tendinous
morphology is preserved We must differentiate tenosynovitis of
a spill within the common peroneal sheath secondary to a tear of
calcaneofibular ligament (PCL). The ultrasound diagnosis is the
detection of the tendons in a lateral plane relative to the distal portion of
the lateral malleolus, instead of behind it. The dynamic exploration foot
dorsiflexion as both eversion may help identify cases of intermittent
subluxation. In long-standing disease can be observed fusiform thickening
of the peroneal tendons at the tip of the malleolus. The complete tears
of the peroneus brevis tendon (PC) and peroneus longus (PL) are
rare, occurring in the area of the lateral malleolus or midfoot. Seen
in patients with ankle sprains or history of chronic instability,
especially if they suffer widespread diseases (RA, DM,) or treated
with corticosteroids. The peroneal tendon ruptures causing the
inability to eversion of the foot and cavus foot varus.
Important thickening of both peroneal tendons (longus and brevis) associated
with moderate amount of fluid and thickening of the synovial sheath.
Discreet amount of fluid in the common sheath of the peroneal tendons
associated with disorganization and a heterogeneous appearance
peroneus brevis tendon related to longitudinal rupture.
Tenosynovitis of the peroneal tendons and an intratendinous rupture of the short peroneal tendon.
Intratendinous rupture and cyst in the peroneus brevis tendon.
Peroneus quartus with an accessory muscle next to the peroneus longus and brevis tendons.
Tumor next to the peroneal tendons that proved to be a benign fibrous mass.
ANOMALIES POSTERIOR TIBIAL TENDON (TP)
It is the most frequently injured in this compartment, with ruptures
in asymptomatic middle-aged obese women as a result of
widespread disease (RA, seronegative Spondyloarthropathy) or
associated with bone fractures. It causes a gradual collapse of the
medial longitudinal arch with hindfoot valgus deformity and
excessive forefoot pronation.
The presence of small vessels in inflammatory diseases
intratendinosis can simulate a fissuration tendon, confusion can be
ignored using colour Doppler. Another possible diagnostic difficulty is
when the undamaged tendon flexor digitorum longus (FLD) moves back and
simulates the TP unbroken, but it is smaller and in this case we only see in the
groove retromalleolar 1 only tendon.
Ultrasound has also proven to be an effective resource for identifying
alterations associated tendon tenosynovitis serosa and hypertrophic.
Subluxation and dislocation anteriorly and medial TP relative to internal
malleolus is rare and valued sonographically placing the foot in dorsiflexion
with forced supination.
Thickening, moderate amount of fluid surrounding, calcifications and
hyperemia affecting the sheath and the posterior tibial tendon related
to chronic tenosynovitis in patient affects rheumatoid arthritis.
Thickening, moderate amount of surrounding fluid, and calcifications (arrow) affecting the
posterior tibial tendon related to chronic tenosynovitis in patient affects rheumatoid arthritis.
Tenosynovitis of the posterior tibial tendon caused by a bony ridge at the insertion
of the retinaculum. The retinaculum is thickened and the tendon subluxates.
Psoriatic arthritis. Ankle. Grayscale examination.
Posterior tibial tendon on longitudinal (a) and
transverse (b) scan. Marked tendon sheath
widening with homogeneous anechoic aspect
(asterisks) of the content indicating an exudative
tenosynovitis. Note as the normal fibrillar
echotexture is conserved. Hand. Flexor tendons of
second finger. The volar longitudinal (c) and
transverse scan (d) shows a tendon sheath
widening with signs of synovial proliferation,
presence of intense power Doppler signal
surrounding the tendon, and micro interruption of
the margin (arrow). e Wrist. Extensor carpi ulnaris
tendon (sixth compartment of the extensor
tendons; ecu) on lateral longitudinal (e) and
transverse (f) scan. Chronic tenosynovitis with clear
areas of low of echogenicity and loss of the
continuity of tendon fibrils indicative of partial
tendon tear (arrows). Moreover, note the presence
of power Doppler signal within the interruption
indicating still activity of the inflammatory
process. g Dactylitis. Volar longitudinal scan using
the “extended view” technique, showing
proliferative tenosynovitis of the finger flexor
tendon (circle), exudative synovitis of both
proximal and distal interphalangeal joint (white
asterisks) and edema of the peritendinous tissue
(black asterisks). TP posterior tibial tendon, mm
medial malleolus, DP distal phalanx, mp middle
phalanx, cu cubital bone, ft flexor tendons.
Tenosynovitis of the posterior tibial (*1) and flexor digitorum longus tendon (*2)
Tenosynovitis of the posterior tibial tendon, the flexor digitorum tendon and flexor hallucis longus tendon
Tenosynovitis of the tendons on the medial side in the left ankle.
The ligament partial tear ligament shows a hypoechoic
areas swollen with internal focal or diffuse. In the complete
ruptures within the substance of the divided ligament rift is
observed corresponding to the hematoma hypoechoic, and
the free ends of the divided ligament can be and retracted
appreciated corrugated, in contrast with normal
Grade I: Mild stretching of the ligament, without breakage
Grade II: Partial tearing of the ligament
Grade III: Complete tearing.
Degrees depending on the severity of the injury and the
place of employment.
These injuries occur secondary to inversion sprains, with internal rotation of
the foot combined with ankle plantar flexion.
The anterior talar fibular ligament tears (ATFL) usually occur as isolated
involvement (70%) or associated with calcaneal fibular ligament (CFL) (20-40%),
but the posterior talar fibular ligament (PTFL) affects only major trauma
involving ankle dislocation.
ATFL breaks is associated with breakage of the joint capsule and synovial fluid
extravasation into the anterolateral soft ankle, whereas the complete tearing of
CFL can communicate the ankle joint and synovial sheath peroneal tendons.
Rupture of CFL is rarely associated with superior peroneal retinaculum tear.
The CFL is tensioned during dorsiflexion pulling on peroneal tendons laterally,
so that absence of its displacement is sign of a complete tear.
Within a damaged ligament can also observe calcifications that often
correspond to fragments of avulsion bone.
During the ultrasound can be performed forced maneuvers to detect to joint
laxity and ligament injuries. The anterior drawer test is performed with the feet
hanging over the edge of the examination table while the forefoot is pulled
anteriorly when the foot is in plantar flexion and inversion. This maneuver
helps differentiate partial tears (grade II) of the ATFL to complete (grade III),
where the anterior displacement of the talus on the tibia open a crack in the
substance becoming more visible the ligament injury.
The sindesmosys sprains are up to 10% of ankle
injuries, happening in eversion and pronation
movements (like the deltoid ligament injury) and
primarily affect the anterior tibiofibular ligament (ATFL),
the failure is frequently associated with fracture of the
According to the place of employment are 4 degrees,
useful for prognostic evaluation and therapeutic strategy
Grade I: stretch or partial tear of the ATFL
Grade II: complete tearing but only the ATFL
Grade III: complete tear of the ATFL and partial CFL
Grade IV: complete tear of the ATFL and CFL.
The grade I and II injuries usually scarred without any
significant instability, whereas grade III and IV injuries
can cause chronic pain and require surgical treatment.
Thickened but continued ATFL right in relation to the partial rupture.
Discontinuity of the ATFL with fluid surrounding the torn ends (arrow).
Thickening and hypoechogenicity of the fibular end of the ligament seen
here passing over the subtalar joint which contains a small of fluid.
Complete disruption to the tibiofibular ligament with bony
irregularity of particularly the tibial margin and fluid in the gap.
Because of the low incidence of eversion ankle
sprains and the thickness of the deltoid ligament
is rarely injured in isolation and when the injury
does not usually full thickness. Usually
accompanied by lesions of the medial malleolus
and lateral displacement of the talus, with
consequent widening of the ankle mortise.
Ultrasound is useful for differentiating ligament
injury of the posterior tibial tendon injury
(TP) adjacent, they have similar symptoms.
The inability to visualize the deltoid ligament may
indicate tear , but this is not considered a reliable
sign as its full ultrasound is not always possible.
Ultrasonogram showing a disrupted deltoid ligament with the probe in the coronal plane. The
white arrow indicates the medial malleolus, the blue arrow indicates the talus, and the red
arrows indicate the disrupted deltoid ligament (A). Radiograph showing the same injury (B).
•JOINT AND BONE DISORDERS
Ultrasound reliably detect spills mild (> 2 ml) inside
of the ankle joint, by exploring the front and rear
recess as well as areas of synovial proliferation, and
may even display using the colour Doppler
hyperemic areas, in arthritis patients.
The intraarticular joints are displayed surrounded
fluid in one of the recesses of the ankle or subtalar
joint. Sonographically diagnosed when changing
position to perform flexion and extension. Fracture of
the lateral process of the talus is overlooked up to 50% of
cases with plain radiography. Ultrasound may suspect the
presence of focal cortical disruption, helping further to
exclude concomitant ligament injury
Rheumatoid arthritis with synovial thickening (*1) and erosion of the tibia (*2)
Infectious arthritis with a pus filled anterior recess of the ankle.
Arthritis and tenosynovitis of the ankle in a patient with rheumatoid arthritis.
Ultrasound can differentiate between a mass complex
and solid and a cystic, in addition to verifying the
existence of accessory muscles (peroneus fourth,
accessory flexor digitorum longus and accessory
soleus). As in any other location can be found
neoformative soft tissue tumors , inflammatory,
Ganglions of this location are more often symptomatic
and larger with multiple partitions
branched and lobed edges. Differential diagnosis must
be made with tenosynovitis, abscesses, seromas and
Neurogenic tumours are described as pathognomonic
homogeneous hypoechoic oval mass in continuity with
a nerve of origin
Ganglion cysts are non-malignant cystic masses that occur
in association with musculoskeletal structures . They are
sometimes also simply referred to as ganglia or a
ganglion, but should not be confused with the anatomical
The vast majority are anechoic to hypoechoic on
ultrasound and have well defined margins. Many
demonstrate internal septations as well as acoustic
A synovial cyst is a small, fluid-filled sac or pouch that can
develop over a tendon or joint, creating a mass under the
skin. Synovial cyst is rare in ankle joint. A synovial cyst
may or may not be painful, depending on their size and
Ganglion cyst in the foot with bony erosion between navicular and cuneiform bones
Anechoic ganglion situated in the sinus tarsi fat between the talus and calcaneous.
Plantar fasciitis (PF) refers to inflammation of the
plantar fascia of the foot. It is considered the most
common cause of heel pain.
Pain on the undersurface of the heel on weight
bearing is the principal complaint. It can be worse
when weight is borne after a period of rest (e.g. in the
morning) and eases with walking. Passive dorsiflexion
of the toes may exacerbates discomfort.
Often the initial imaging modality of choice.
Ultrasound typically shows increased thickness of the
fascia and a hypoechoic fascia.
Thickened hypoechoic origin of the plantar fascia which has a convex superior margin.
Complete avulsion of the plantar fascia from the calcaneal tubercle.
• LOCATING FOREIGN BODIES AND FRACTURES.
As in any other location, the ankle
area is also subsidiary host foreign
whose classification, location and
existence can be defined perfectly by
ultrasound. Being a focused study to
the area of interest and with great
resolution for surface structures, can
be considered more resolute
examination to screen these cases.
examination of left
ankle. A: Longitudinal
sonogram, left ankle,
wooden foreign body;
B: Transverse view,
left ankle. Note the
the inflamed area; C:
of left ankle. Note the
swelling on the lateral
aspect. No foreign
body is visible.