OK- messing up the images with colour overlays. 


There is a thickened and oedematous Lisfranc ligament (1st intermetarsal space) consistent with Lisfranc ligament sprain/partial tear. 


Note mild widening of the Lisfranc joint. 

The Lisfranc joint injury spans a spectrum from strain to frank dislocation. We've talked about it here before. 


The Lisfranc ligament is also called the first intermetatarsal ligament and bridges the medial cuneiform with the base of the 2nd metatarsal. The other metatarsals are connected by intermetatarsal ligaments which are transverse in orientation. The 1st intermetarsal joint has no transverse ligament. This effectively jams the base of the 2nd metatarsal into the cuneiform on weight-bearing (a keystone effect).


Lisfranc injuries manifest as a step off at the base of the 2nd metatarsal relative to the cuneiforms. Patients also cannot tip-toe due to pain.

Chronic ankle pain. Sagittal PD fat sat and coronal PD.

Nice example of osteochondral injury involving the cartilage tidemark. There are multiple subchondral cysts, and bone oedema. This is quite classic of inversion injuries, with impaction injury between the talus and distal tibia. The important thing, of course, is to make sure that there is no detached osteochondral fragment. For that, follow the cartilage lining from end to end, and the overlying cortex. Make sure there are no cortical disruptions.

Swelling left side of buttock- 6 months' duration. Sagittal T1, Sagittal PD, Axial T1 and Axial T2 fat sat.

There is a loculated fluid collection with septation, and multiple fluid levels (see axial T2 fat sat image). It's adjacent to the left ischial tuberosity. There's a thick rim around the lesion.


Ischial bursitis: also called weaver's bottom

Let's play Name That Structure!

Write in with your answers!

OK- so the female patient's breast MRI reveals something quite interesting. Previous ultrasound done at St Elsewhere revealed no focal mass. Agree?

Well, let's go back to the ultrasound images. If you compare the right breast with the left, you'll find that there's asymmetry in the images. There's a hypoechoic focus in the left breast, with thin linear septation. Of course, on MRI you see that there is an intermuscular lipomatous lesion, with some intramuscular components. And you remember that in the breast, fat is hypoechoic- as opposed to other body parts where fat is hyperechoic.


So, sometimes if it's too big you can walk past it. God gave us duplicate body parts to compare.

OK- not a musculoskeletal case. But a nice one anyway. Sagittal T1W, axial diffusion, axial T2W, axial FLAIR and axial T1W.

Epidermoid cyst. Extra-axial. 1% of intracranial lesions. Rarely rupture compared with dermoid cysts (which cause chemical meningitis). Likely congenital- and grow very slowly. 


Read about it here.

As you can see, the images were taken with the knee in semiflexion. We usually acquire them in extension. Bad scan?

So- it's not a bad scan. Pixellated - but that's poor photoshopping.
There's a bucket handle medial meniscus tear (thanks, Dr TS!) with displaced fragment within the intercondylar notch. It's getting in the way of full extension. A classic case of locking.


You see the remnant anterior and posterior horns of medial meniscus, with loss of free edge. The remnants are small- and that's your first clue that it's torn. Scroll slowly, and you see the flipped fragment in the intercondylar notch (look at axial image). The bucket handle is easy to miss because it can blend with the cortex of the intercondylar notch, so be careful. And don't dismiss it as a bad scan.

Coronal and axial T2 fat sat images of the lower limbs. This, taken from a guy who ran a marathon without adequate training.


The images reveal oedema in the gastrocnemius muscles bilaterally, with fluid in the gastrocsoleus myotendinous junction. This is a grade 2/3 myotendinous junction tear. You can see this in tennis players, but bilateral changes are somewhat less common.


Grading of myotendinous junction injuries is as follows:
Grade 1- oedema, without disruption.
Grade 2- partial tear of the myotendinous junction with oedema/haemorrhage
Grade 3- complete tear with oedema and haemorrhage

Image on left is a coronal PD through the midfoot, and fat saturated PD on the right. What do you see?

There's thickening of the Lisfranc ligament (the ligament connecting the medial cuneiform with the base of the 2nd metatarsal bone). There's no joint widening, and no fracture- and would be radiographically occult.


In civil society, this injury can be sustained during football injuries (or kicking someone's tires). In Napoleon's day, you would have a carriage roll over your foot, causing a fracture. Jacques Lisfranc, after whom the injury is named, is taught to treat this injury with a mid-forefoot amputation.


Ligament injuries can be classified as sprains or tears (in which case, there's discontinuity of the ligament). Clinically, there's localised tenderness and pain when squeezing the midfoot.


The injury is well demonstrated on a PD nonfat sat image- so look carefully.