Tendons of the Pes Anserinus Mnemonic
↧
↧
Gracile Bones Mnemonic – NIMROD
This mnemonic has been commonly used to recall the differential diagnosis for gracile bones – NIMROD
N – Neurofibromatosis
I – Immobilization (Paralysis)
M – Muscular Dystrophy
R – Rheumatoid Arthritis
O – Osteogenesis Imperfecta (click the link or see below)
D – Dysplasias (Marfan’s syndrome, Homocystinuria)
Osteogenesis Imperfecta: Radiograph of the bilateral lower extremities reveals marked bowing deformities of the femurs, tibias, and fibulas with a background of diffuse osteopenia. The tibia and fibula also have a gracile diaphysis appearance, or overtubulation.
Filed under: Mnemonics, MSK Tagged: diaphysis, mnemonic, MSK
↧
Enchondroma – Phalanx
History: 35 year old male with hand pain.
Enchondroma – frontal radiograph of the right hand reveals a lytic lesion in the fourth proximal phalanx (yellow arrow) with subtle areas of calcified matrix within the lesion compatible with an enchondroma.
This is a classic appearance of an enchondroma in a phalanx on radiographs. An enchondroma is a benign cartilaginous tumor that arises from the medullary space of the bone. Enchondromas are the second most common benign tumor of bones (after osteochondroma) and most common benign tumor of small tubular bones, as seen here in the fourth proximal phalanx of the hand.
On MRI, enchondromas are characteristically lobulated with homogeneous hyperintense signal on fluid sensitive sequences, typical of benign cartilaginous lesions. Ideally, contrast is required to definitively distinguish between enchondromas and low grade chondrosarcomas, as some enchondromas can degenerate into chondrosarcomas. This is shown radiographically by excessive endosteal scalloping, and on MRI with contrast as peripheral puddling of contrast within the lesion. Another distinguishing factor is pain, indicating likely chondrosarcoma. Read more about other distinguishing findings here.
In the setting of multiple enchondromas, consider Ollier’s disease. In the setting of multiple enchondromas with soft tissue hemangiomas, consider Mafucci’s syndrome.
See an Enchondroma of the tibia on MRI here.
See the differential diagnosis for lytic bone lesions here.
Filed under: MSK Tagged: enchondroma, lytic lesion, MSK, phalanx
↧
Male versus Female Pelvis – Labeled Radiographic Anatomy
↧
Giant Cell Tumor of Tendon Sheath
History: Male with foot mass.
Giant Cell Tumor of Tendon Sheath – Sagittal T1 weighted MRI of the foot reveals an oblong hypointense mass on the dorsum of the foot (yellow arrow). This is a characteristic appearance of giant cell tumor of tendon sheath.
Giant Cell Tumor of Tendon Sheath – sagittal STIR sequence shows the mass is hyperintense with areas of internal low signal reflecting hemosiderin deposition and fibrous septations.
This is a nice example of a giant cell tumor of tendon sheath, which essentially is a benign proliferation of synovium within the tendon sheath. Giant cell tumors of tendon sheath (GCTTS) are the second most common benign tumors in the fingers after ganglion cysts. On MRI as shown above, GCTTS are classically hypointense to isointense on T1 and have foci of low internal signal on T2 weighted images due to hemosiderin and fibrous septations. On post-Gadolinium images they have diffuse enhancement which can appear heterogeneous.
The differential diagnosis in this case would include entities such as tenosynovitis, ganglion cyst, and peripheral nerve sheath tumors such as Schwannoma and Neurofibroma.
Read an article on giant cell tumors of tendon sheath here.
Filed under: MRI, MSK Tagged: Foot, MRI, MSK
↧
↧
Clavicle Fracture
History: child with left shoulder pain after bicycle accident.
Clavicle Fracture – a fracture is seen at the mid left clavicle (yellow arrow) with mild apex cephalad angulation.
This is a typical clavicle fracture in children with mild apex cephalad (pointing upward towards the head) angulation. This clavicle fracture actually exhibits full thickness break through the bone cortex, but children can frequently have incomplete fractures. These are referred to as buckle fractures (or torus fractures, from the Latin word “tori” meaning protuberance or swelling), greenstick fractures, and plastic bowing fractures. Here is the difference:
Buckle fractures: angular deformity found at the site of compression impact, opposite side cortex of bone is intact.
Greenstick fractures: fracture of the cortex opposite the side of impact (the tension, convex side)
Plastic bowing fracture: bowing deformity without visible fracture lines. See one here.
Filed under: MSK, Pediatrics Tagged: clavicle, MSK, pediatrics
↧
Lateral Epicondyle Avulsion Fracture
History: child with elbow pain.
Lateral epicondyle avulsion fracture – frontal radiograph of the left elbow reveals a fragment of bone (yellow arrow) which has been pulled from the lateral epicondyle by the common extensor tendon. Additionally, the fragment appears to be rotated laterally.
This is an example of a lateral epicondyle avulsion fracture in a child, which is a very rare epicondyle fracture and much less common than medial epicondyle fractures. A lateral epicondyle fracture is due to an avulsion of the lateral epicondyle by excessive force from the common extensor tendon, which is the shared origin of the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris.
With the above amount of displacement and rotation of the bone fragment, open reduction internal fixation will have to be performed. In general, >5mm of displacement requires internal fixation, which will usually be done with Kirshner wires in young children and screws in older children. If improper healing occurs, varus instability can occur.
It is important to understand the sequence of ossification in the pediatric elbow to be able to correctly interpret a pediatric elbow radiograph for possible injury. See this mnemonic here for elbow ossification centers.
Filed under: MSK, Pediatrics Tagged: elbow, MSK, pediatrics
↧
Pediatric Femur Anatomy
The following images are from WikiRadiography (WetPaint) here.
See a pediatric femur fracture here.
Filed under: Anatomy, MSK, Pediatrics Tagged: anatomy, femur, MSK, pediatrics
↧
Pediatric Knee Anatomy
The following images are from WikiRadiography (WetPaint) here .
Filed under: Anatomy, MSK, Pediatrics Tagged: anatomy, knee, MSK, pediatrics
↧
↧
Bone Infarcts
History: 55 year old male with knee pain.
Osteonecrosis of the Knee – Lateral radiograph of the right knee reveals large well defined serpentine regions of sclerosis in the proximal tibia and distal femur (yellow arrows). There is also be mild flattening of the tibial plateau and femoral condyle articular surfaces. This is representative of osteonecrosis of the knee, otherwise called bone infarcts.
This is a classic example of bone infarcts, here called osteonecrosis of the knee, which on radiographs is represented as a well defined sclerotic lesion with serpentine margins. In our example, the articular surfaces are mildly distorted, more so on the tibial plateau, causing collapse.
On MRI, bone infarcts in the acute phase are dark on T1 weighted images and bright on T2 weighted images, representing edema. The double line sign is diagnostic of bone infarcts, which is seen on T2 weighted images as a high-signal-intensity line within a parallel rim of decreased signal intensity. Read more about the double line sign here.
The differential diagnosis here includes spontaneous osteonecrosis of the knee, which usually involves the medial femoral condyle and middle age and older females, and regional migratory osteoporosis, which you can read more about here.
Filed under: MSK Tagged: Bone, bone infarcts, femur, knee pain, MSK, tibia
↧
More Pages to Explore .....
