ABC Radiology Blog

Fabella and cyamella

noreply@blogger.com (ABC RADIOLOGY BLOG) — Thu, 29 Jan 2026 09:06:04 +0000

● The fabella is a small sesamoid bone found embedded in the tendon of the lateral head of the gastrocnemius muscle behind the lateral condyle of the femur.

● The fabella can also be fibrocartilaginous in nature and is occasionally found in the medial head of the gastrocnemius. The fabella articulates with its respective (medial or lateral) femoral condyle.

● It is an accessory bone, an anatomical variation present in 39% of humans.

● Rarely, there are two or three of these bones (fabella bi- or tripartita).

● It can be mistaken for a loose body or osteophyte.

● The word fabella is a Latin diminutive of faba 'bean'.

● It is more common in men than women, older individuals compared to younger, and there is high regional variation, with fabellae being most common in people living in Asia and Oceania and least common in people living in North America and Africa.

● Bilateral cases (one per knee) are more common than unilateral ones (one per individual), and within individual cases, fabellae are equally likely to be present in right or left knees.

● The fabella can lead to posterolateral knee pain either due to cartilage softening (chondromalacia fabellae) or other osteoarthritic changes on its articular surface.

● The most relevant differential diagnosis is the cyamella which is a rare sesamoid bone that exists as a normal variant within the popliteus tendon, characteristically located at the posterolateral aspect of the distal femur in the popliteal groove.

■ A cyamella (sometimes called popliteal fabella, fabella distalis, sesamoideum genu inferius laterale).

■ Cyamella is best seen on the AP view of plain radiograph as opposed to the fabella, which is located in the lateral head of the gastrocnemius and best appreciated on the lateral view.

■ It is round/ovoid, sometimes flattened and generally smaller than fabella.

■ Three locations have been described :

▪︎ Lateral to lateral femoral condyle, near popliteal sulcus (origin of popliteus tendon).

▪︎ Lateral to tibial condyle, near tibial plateau and fibular head (close to popliteofibular ligament).

▪︎ Between tibia and fibular head, posteromedial to tibiofibular joint (distal popliteus).

Chopart fracture-dislocations

noreply@blogger.com (ABC RADIOLOGY BLOG) — Wed, 03 Dec 2025 11:09:00 +0000

● Chopart fracture-dislocations occur at the midtarsal (Chopart) joint in the foot, i.e. talonavicular and calcaneocuboid joints which separate the hindfoot from the midfoot. The commonly fractured bones are the calcaneus, cuboid and navicular.

● The foot is usually dislocated medially and superiorly as it is plantarflexed and inverted, usually as a result of a high-energy impact, e.g. fall from height or road traffic collision. Where the foot is everted, lateral displacement occurs.

● The Cyma line can also be disrupted.

Cyma line

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sun, 23 Nov 2025 08:44:00 +0000

● A cyma line refers to the union of two curved lines in architecture and comes from the Greek word kyma meaning wave.

● The cyma line is a radiological sign of the smooth joining of the midtarsal joint lines as a "lazy S-shape" of the talonavicular and calcaneocuboid joints on both AP and lateral views.

● Disruption of the cyma line with anterior shift of the talonavicular joint can indicate true shortening of the calcaneus or rotation of the talus relative to the calcaneus as seen in pes planus that is shown in the following image.

● The cyma line can also be disrupted in a midtarsal (Chopart) injury.

The Blumensaat line

noreply@blogger.com (ABC RADIOLOGY BLOG) — Fri, 21 Nov 2025 19:30:00 +0000

The Blumensaat line, also known as the intercondylar line, is a key anatomical landmark on the femoral condyle used to evaluate the anterior cruciate ligament (ACL). It is a line corresponding to the roof of the intercondylar fossa of the femur as seen on a lateral knee X-ray or MRI.

Significance of the Blumensaat Line for an Intact ACL:

● Orientation: In a healthy, intact knee, the normal ACL fibers appear steeper and parallel to the Blumensaat line on a sagittal MRI or X-ray.

● Angle: The angle between an intact ACL and the Blumensaat line is typically less than 15 degrees.

● Positioning: The normal femoral attachment of the ACL is on the posterior part of the medial surface of the lateral femoral condyle, with the center of its footprint located in a consistent position relative to the Blumensaat line.

Signs of an Injured ACL in Relation to the Line:

● Abnormal Orientation: An ACL tear is indicated if the angle between the ligament and the Blumensaat line increases (typically >15 degrees), appearing less steep or "flattened".

● Discontinuity: The line can help highlight a lack of continuity in the ACL fibers if they do not reach their normal attachment point in the intercondylar notch.

● Empty Notch Sign: In cases of avulsion at the femoral attachment, fluid signal may be visible at the site where the ACL should insert in the intercondylar notch, which borders the Blumensaat line region.

Patellar tendon lateral femoral condyle friction syndrome

noreply@blogger.com (ABC RADIOLOGY BLOG) — Fri, 07 Nov 2025 18:16:22 +0000

Patellar tendon lateral femoral condyle friction syndrome, also called Hoffa fat pad impingement syndrome, is a condition causing anterior knee pain from the superolateral infrapatellar fat pad being compressed between the patellar tendon and the lateral femoral condyle.

It is often linked to patellar maltracking or muscle imbalances and can result in pain, tenderness, and difficulty with activities like running or squatting. Treatment can involve conservative methods like activity modification and physical therapy, or surgery if conservative options fail.

Ponticulus posticus of atlas vertebra

noreply@blogger.com (ABC RADIOLOGY BLOG) — Wed, 05 Nov 2025 10:28:18 +0000

☆ The ponticulus posticus means "little posterior bridge" in Latin.

☆ Ponticulus posticus occurs due to calcification of the oblique atlanto-occipital ligaments and is known by many names such as Kimerle foramen, foramen arcuale atlantis or arcuate foramen.

☆ It was defined as an abnormal small bony bridge formed between the posterior portion of the superior articular process and the posterolateral portion of the superior margin of the posterior arch of the atlas.

☆ It has a variable morphology, can be complete or incomplete and may be unilateral or bilateral.

☆ Literature reveals a higher incidence in females compared with males and this anomaly was age independent.

☆ The sulcus situated on the posterolateral margin of the atlas forms a groove for the vertebral artery. The vertebral artery (atlantic portion V3 ) passes through this foramen.

Common total hip arthroplasty postoperative radiographic findings and complications around the prosthesis

noreply@blogger.com (ABC RADIOLOGY BLOG) — Mon, 03 Nov 2025 15:11:00 +0000

This image is an annotated X-ray of a total hip arthroplasty (THA) showing common postoperative radiographic findings and complications around the prosthesis. Here's a clear breakdown of each labeled term:

🔶 Heterotopic Ossification:

Definition: Bone formation in soft tissues where bone normally does not exist.

Radiographic finding: Irregular ossification around the joint, usually periarticular.

Clinical note: Common after hip surgery; may restrict motion.

🔶 Stress Shielding:

Definition: Localized bone loss (osteopenia) due to altered load distribution — the metal prosthesis bears more stress than the bone.

Radiographic finding: Thinning of the proximal femoral cortex, especially in the calcar region.

🔶 Aseptic Loosening:

Definition: Failure of the bond between bone and prosthesis without infection.

Radiographic finding: Periprosthetic lucent zones (>2 mm), often progressive, around the stem or cup.

Mechanism: Micromotion and fibrous tissue interface formation.

🔶 Septic Loosening:

Definition: Loosening due to infection.

Radiographic finding: Rapidly progressive lucency with periosteal reaction or bone destruction.

Key distinction: Infection causes aggressive and irregular bone changes compared to aseptic loosening.

🔶 Spot Welding:

Definition: Endosteal bone formation in direct contact with the prosthesis.

Radiographic finding: Localized areas where bone density increases along the stem — indicates good osseointegration (favorable sign).

🔶 Fibrous Membrane:

Definition: Thin fibrous interface (< 2 mm) between bone and prosthesis.

Radiographic finding: Narrow radiolucent line with a thin sclerotic border — often stable and non-progressive.

🔶 Periprosthetic Fracture:

Definition: Fracture of the bone surrounding the prosthesis, usually due to trauma or stress.

Radiographic finding: Commonly occurs near the tip of the femoral stem.

Classification: Often described by the Vancouver classification (location and implant stability).

🔩 Common Fixation Devices Used for AC Joint / Distal Clavicle Surgery

noreply@blogger.com (ABC RADIOLOGY BLOG) — Thu, 23 Oct 2025 08:39:00 +0000

🔩 Common Fixation Devices Used for AC Joint / Distal Clavicle Surgery:

1. Hook Plate – a contoured plate that hooks under the acromion to stabilize the distal clavicle.

Radiographically: long plate along the clavicle with a hook projecting beneath the acromion.

2. Clavicular Locking Plate – low-profile plate with multiple screws along the distal clavicle.

Radiographically: several screws seen linearly along the clavicle.

3. EndoButton / TightRope (Suture-Button Device) – two small metallic buttons connected by a high-strength suture for coracoclavicular ligament reconstruction.

It is a suture-button device used to stabilize the coracoclavicular (CC) joint, typically for severe acromioclavicular (AC) joint separations or distal clavicle fractures. The surgical procedure involves drilling tunnels through the clavicle and coracoid process and then passing a strong suture with two buttons through these tunnels.The buttons are then secured on either side of the bone, effectively mimicking and reinforcing the natural CC ligaments, which holds the clavicle and coracoid together.

Radiographically: On standard AP or scapular Y views:

Superior button (clavicular side): appears as small, round or rectangular metallic opacity over the superior surface of the distal clavicle. Usually the most visible part (seen end-on).

Inferior button (coracoid side): Often faint or obscured by overlying bone of the coracoid or glenoid. May appear as a second small metallic density inferior to the clavicle, but not always distinct on AP view.

Connecting suture is radiolucent (not seen). Only the buttons are radiopaque.

Double J Ureteric Catheter (DJ Stent)

noreply@blogger.com (ABC RADIOLOGY BLOG) — Wed, 22 Oct 2025 19:43:00 +0000

1. Definition & Purpose:

A Double J stent is a thin, flexible tube placed in the ureter to ensure urine drainage from the kidney to the bladder.

The term “Double J” refers to the curled (J-shaped) ends — one in the renal pelvis and the other in the bladder, preventing migration.

2. Indications:

● Post-ureteric surgery (e.g., pyeloplasty, ureteric reimplantation)

● Obstructive uropathy (stone, tumor, stricture, edema)

● Post-lithotripsy or ureteroscopy

● Urinary leak prevention (after trauma or

surgery)

3. Imaging Appearance:

Modality Appearance / Key Points

● X-ray KUB : Radiopaque linear tubular structure with curled ends—one in renal pelvis, one in bladder. Verify both ends visible and in correct position.

● CT (non-contrast) : Clearly visualized as a hyperdense linear structure along ureter’s course. Confirms position and checks for obstruction, migration, or encrustation.

● Ultrasound : Echogenic line with posterior shadow; sometimes only proximal/distal curls seen. Used to detect hydronephrosis or stent-related complications.

● Fluoroscopy Used during insertion/removal—real-time visualization of correct coil placement.

4. Correct Position:

● Proximal end: in renal pelvis or upper calyx.

● Distal end: within bladder lumen.

● Shaft follows ureteric path without kinking.

5. Complications & Radiologic Findings:

Complication, Imaging Findings / Notes

● Migration / Malposition Coil seen outside expected area (e.g., proximal coil in ureter or distal coil in urethra).

● Encrustation / Calcification Irregular hyperdense deposits along stent; better seen on CT or X-ray.

● Fragmentation / Fracture Discontinuity of stent; may cause obstruction.

● Infection / Pyelonephritis. In CT displayed as: perinephric stranding and hydronephrosis.

● Forgotten stent : Encrustation, stone formation and hydronephrosis.

🦵 TYPES OF ACL REPAIR & RECONSTRUCTION TECHNIQUES

noreply@blogger.com (ABC RADIOLOGY BLOG) — Wed, 22 Oct 2025 16:14:00 +0000

🔹 Primary ACL Repair (Direct Repair)

Definition: Reattachment of the torn native ACL to its femoral or tibial footprint, preserving the original ligament.

Indications:

Proximal (femoral-sided) tears

Good tissue quality

Often in acute injuries (<3 weeks old)

Techniques:

Suture anchor repair (reattaching ACL to femoral wall)

Suture augmentation/internal brace (using FiberTape or similar to protect repair during healing)

Examples:

Arthroscopic primary ACL repair with suture anchors (e.g., “BEAR,” “InternalBrace”)

🔹 Biologic-Enhanced ACL Repair

Definition: Augmenting primary repair with biological scaffolds to improve healing.

Types:

BEAR (Bridge-Enhanced ACL Repair): Uses a collagen scaffold saturated with autologous blood to bridge torn ends.

Stem cell or PRP-assisted repair: Under research; aims to enhance ligament healing biologically.

🔹 ACL Reconstruction (Graft-Based Replacement)

When native ACL cannot be repaired (most common), a graft is used to reconstruct it.

a. Autograft Reconstruction

Using patient’s own tissue:

Hamstring tendon graft (most common)

Bone–Patellar Tendon–Bone (BPTB) graft

Quadriceps tendon graft

Each has different pros/cons:

Graft Advantages Disadvantages

Hamstring Smaller incision, less anterior knee pain Slower graft incorporation

BPTB Bone-to-bone healing, strong fixation Anterior knee pain, kneeling discomfort

Quadriceps Good graft size, less donor-site pain May cause temporary extensor weakness

b. Allograft Reconstruction

Uses donor tissue (e.g., Achilles, tibialis anterior)

Pros: shorter surgery, no donor morbidity

Cons: slower incorporation, higher re-tear rate (especially in young athletes)

🔹 Hybrid Techniques

Combination of repair and reconstruction — for example:

Augmented repair + partial graft if some ACL fibers remain intact.

ACL remnant-preserving reconstruction to retain proprioceptive fibers.

🔹 Dynamic Intraligamentary Stabilization (DIS)

Technique: Uses a dynamic spring screw (e.g., Ligamys system) to stabilize ACL during healing.

Goal: Promotes natural healing while preventing anterior tibial translation.

The intramedullary nail

noreply@blogger.com (ABC RADIOLOGY BLOG) — Mon, 20 Oct 2025 12:11:00 +0000

An intramedullary nail is a metal rod inserted into the medullary cavity of a long bone to treat fractures. This surgical procedure stabilizes the bone, acting as an internal splint to help the bone heal and allowing for earlier weight-bearing. Common bones treated with this method include the femur, tibia, and humerus.

Bile duct

noreply@blogger.com (ABC RADIOLOGY BLOG) — Mon, 20 Oct 2025 11:55:00 +0000

A bile duct is a tube that carries bile from the liver and gallbladder to the small intestine, where it helps digest fats. The system includes both tubes within the liver (intrahepatic) and tubes outside the liver (extrahepatic). Blockages in the bile ducts can lead to health problems, such as gallstones or cancer, causing symptoms like jaundice.

Hallux Valgus

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 18 Oct 2025 19:18:00 +0000

Hallux Valgus, commonly referred to as a bunion, is a complex valgus deformity of the first ray that can cause medial big toe pain and difficulty with shoe wear.

Diagnosis is made clinically with presence of a hallux that rests in a valgus and pronated position. Radiographs of the foot are obtained to identify the severity of the disease and for surgical planning.

Treatment can be nonoperative with shoe modifications for mild and minimally symptomatic cases. Surgical management is indicated for progressive deformity and difficulty with shoe wear.

Os vesalianum vs os peroneum

noreply@blogger.com (ABC RADIOLOGY BLOG) — Thu, 16 Oct 2025 22:28:00 +0000

The os peroneum is an accessory bone found within the peroneus longus tendon near the cuboid bone, while the os vesalianum is a rare accessory bone located near the base of the fifth metatarsal within the peroneus brevis tendon. The os peroneum is a more common accessory ossicle, whereas the os vesalianum can be confused with an avulsion fracture of the fifth metatarsal. Painful os peroneum syndrome typically involves the peroneus longus tendon, while a symptomatic os vesalianum can cause pain near the base of the fifth metatarsal.

NAME THE STRUCTURE SERIES VIDEO NUMBER 3

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 07 Mar 2020 14:50:00 +0000

NAME THE STRUCTURE SERIES VIDEO NUMBER 1

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 07 Mar 2020 12:54:00 +0000

NAME THE STRUCTURE SERIES VIDEO NUMBER 2

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 07 Mar 2020 12:50:00 +0000

Milkman Fracture

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 28 Dec 2019 10:56:00 +0000

Milkman Fracture ⏩

Breast mouse

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sat, 20 Apr 2019 14:09:00 +0000

Zinner syndrome

noreply@blogger.com (ABC RADIOLOGY BLOG) — Thu, 18 Apr 2019 12:49:00 +0000

Artificial intelligence in radiology

noreply@blogger.com (ABC RADIOLOGY BLOG) — Fri, 22 Mar 2019 18:26:00 +0000

Breast MRI

noreply@blogger.com (ABC RADIOLOGY BLOG) — Mon, 18 Mar 2019 13:19:00 +0000

Toxic Megacolon

noreply@blogger.com (ABC RADIOLOGY BLOG) — Thu, 28 Feb 2019 22:20:00 +0000

Fibrous Dysplasia

noreply@blogger.com (ABC RADIOLOGY BLOG) — Tue, 12 Feb 2019 21:46:00 +0000

Irreversible electroporation

noreply@blogger.com (ABC RADIOLOGY BLOG) — Sun, 29 Nov 2015 13:14:00 +0000

Irreversible electroporation (IRE or NTIRE for non-thermal irreversible electroporation) is a soft tissue ablation technique using ultra short but strong electrical fields to create permanent and hence lethal nanopores in the cell membrane, to disrupt the cellular homeostasis.
The resulting cell death results from apoptosis and not necrosis as in all other thermal or radiation based ablation techniques.
The main use of IRE lies in tumor ablation in regions where precision and conservation of the extracellular matrix, blood flow and nerves are of importance. The technique is in an experimental stage and has not been approved for use outside of clinical trials.
Utilizing ultra short pulsed but very strong electrical fields, micropores and nanopores are induced in the phospholipid bilayers which form the outer cell membranes.
A number of electrodes, in form of long needles, are placed around the target volume. The point of penetration for the electrodes is chosen according to anatomical conditions. Imaging is essential to the placement and can be achieved by ultrasound, magnetic resonance imaging or tomography. The needles are then connected to the IRE-generator, which then proceeds to sequentially build up a potential difference between two electrodes. The geometry of the IRE-treatment field is calculated in real time and can be influenced by the user. Depending on treatment-field and number of electrodes used, the ablation takes between 1 to 10 minutes of time. In general muscle-relaxants are administered, since even under general anaesthetics, strong muscle-contractions are induced by excitation of the motor end-plate.
One specific device for the IRE procedure is the so-called The NanoKnife system manufactured by AngioDynamics which has received premarket notification from the FDA.

Scope of applications:

Prostate: Using IRE, the urethra, bladder, rectum and neurovascular bundle can potentially be included in the treatment field without taking (permanent) damage. This would potentially give IRE superiority both for focal therapy and whole gland treatments compared to all other available methods.
Liver, kidney, and pancreas: Several inoperable tumors of the liver and the kidney can be treated using IRE. This is due to tissue selectivity regarding blood vessels and epithelial type tissue.
Other organs: the feasibility of IRE for breast cancer and other heterogeneous tissue organs have been reported.