MSK Flashcards
Pathological vertebral fracture vs osteoporotic
Bone marrow on MRI
Tarlov cyst
-Dilatation of posterior nerve root sheath.
Dural ectasia
- Ballooning of the dural sac resulting in posterior vertebral scalloping
Disc Bulging and nerve compression
- In cervical spine C3/C4 will affect C4 etc
Causes of Marrow Reconveresion
Myelofibrosis
Bone marrow is gradually replaced by fibrous tissue
Fibrous tissue contains fewer water molecules
Low signal T1 + T2
Concurrent hepatosplenomegally
Cause of a super scan
Vertebral haemangioma
Typical: High signal T1 + T2 (Lipid rich)
Atypical: Low T1, high T2 (Lipid poor)
Avid enhancement
Sign—lateral (corduroy)
Differential for permeative bone destruction
Nerve compression secondary to disc bulging
Posterior vertebral scalloping
- SATAN
Anterior vertebral scalloping
Myotomes
Dermatomes
Osteoporosis v mets
Causes for block vertebrae:
Sprengel shoulder
Can occur in isolation or as part of Klippel-Feil syndrome
- both associated with renal anomalies
Congenital abnormality where scapula is attached to the cervical vertebrae by fibrous or osseous (omovertebral) connection
Result is elevation and medial rotation of hypoplastic scapula.
- CAN BE SEEN ON PLAIN FILM
Klippel - Feil syndrome
Segmentation anomaly with cervical fusion of 2or more vertebrae. C2-C3 most commonly involved.
Other associations:
Renal abnormalities
Scoliosis
Sprengel shoulder
Deafness (SN) (Nbb microtia, deformed ossicles)
Cervical ribs
Congential heart disease - ASD
Ivory vertebrae - dense sclerosis of a solitary vertebrae without change in size/shape
Holt-Oram syndrome
Associated with numerous skeletal and cardiac malformations
Cardiac : ASD, VSD, tetralogy of Fallot, coarctation.
MSK: Radial ray hypoplasia - absence of one or both thumbs
Ependymoma
T1 hypointense, foci high T2 signal
Predominate in 4th ventricle (roof)
Toothpaste tumour
Spinal cord ependymoma is slightly different - most common intramedullary tumour in adult which shows intense enhancement
Can be associated with syrinx
NF2 - spinal ependymoma
Hemangioblastoma
Cyst with enhancing nodule
ISO or high T1, high T2.
Sometimes cause polycythaemia.
Phemister triad - features of articular tuberculosis
Tuberculous spondylitis known as Pott disease
- L1 usually first affected
- anterior vertebrae affected first because of bacterial spread anterior longitudinal ligament
- Juxta-articular osteoporosis
- Marginal erosions
- Gradual reduction in joint space
Tuberculous spondylitis v pyogenic spondylitis
Widened interpedicular distance
Diastomatomyelia
Split cord
Two Dural sac type 1, one sac type 2
Disc terminology
Increased Atlantodental interval
Normal
- adults <3mm
- children <5mm
Also prevertebral space
- <7mm at c2
- <5mm C3/4
- <22mm C6 (14mm kids)
Paget’s disease
Lytic phase: radiolucency with flame or blade of grass shape extends along the diaphysis. Osteoporosis circumscripta (lucent areas in skull).
Mixed phase: lytic and sclerotic
Sclerotic phase: densely sclerotic eg ivory vertebrae.
Clinically :
Raised ALP, normal Ca and phosphate
Pathological fracture although sclerotic
CN palsy secondary to neural foramina compression
Enlarging head/hat - Tam O’Shanter
Radiologically: bony expansion with coarsening of trabecular and cortices.
Hyperparathyroidism
PTH increases calcium levels prompting renal re absorption or acting on osteoclasts to increase bone resorption.
Therefore generalised osteopenia, cortical thinning of subperiosteal bone.
Osteoporosis
- loss of bone mass
Susceptible to fracture
- typically Colles fracture
- NOF fracture
DEXA
Density of bone calculated
Z score
Causes:
Osteogenesis Imperfecta
Chromosome 7/17
Abnormal type 1 collagen
- Autosomal dominant fashion
On imaging diffuse undermineralisation of skeleton and cortical thinning.
Soft bones become bowed
Acetabula protrusion
Basilar invagination (C-spine v base of skull)
Wormian bones
Madelung deformity
- problem with ulnar side of the distal radius
- distal radioulnar joint subluxes and ulna displaces dorsally
- positive ulnar variance
- lunate is triangular
- radioulnarcarpel joint angle <120 degrees
Pseudo gout - CPPD
Can be acute or subacute
- similar characteristics to OA
Particular joint involvement
- patellofemoral joint
- TFCC calcification
- Radiocarpal joint
Median nerve supply
L lateral 2 lumbricals
O Opponens policis
A Abductor pollicis brevis
F Flexor pollicis brevis
Carpel tunnel
Alkaptonuria (Ochronosis)
Autosommal recessive
Raised enzyme - HGA
Affinity for collagen and accumulates in CT throughout the body.
Causes a black staining
Chondrocalcinosis most prominent feature
Calcification and destruction intervertebral discs.
Premature OA changes hands, feet, shoulders, hips, knees.
Haemachromatosis
Primary - excessive dietary iron accumulation
Secondary - blood transfusions with too little chelation.
On MRI
Iron paramagnetic, and therefore liver will be lower than expected, but spleen normal
Transfusion also siderosis spleen/bone marrow affected.
Wilsons - excess copper
Enteropathic arteropathy
