Di Imaging Exam 2

What is enchondral ossification?

cartilage is the precursor on which new bone is laid down (majority of skeleton)

What is intramembranous ossification?

direct laying down of bone into the primitive tissue, without intermediate cartilage (most of skull, clavicle and fibula)

What is calcification?

laying down of calcium-based salts and crystals within cells and tissues

The primary ossification centers first appear where in spine at 9 weeks in utero followed by _

cervicothoracic junction

upper cervical then thoracolumbar vertebrae

lumbar neural arches is the last to appear at 14 weeks

C3-L5 vertebrae typically have _ primary ossification centers

3→ one in centrum (vertebral body) and one for each half of the neural arch

C1 has how many primary ossification centers in total?

3→ one for anterior arch and one for each side of posterior arch

C2 has how many primary ossification centers?

5→ same as typical vertebrae but has two extra for the dens

C3-L5 vertebrae have _ secondary ossification centers that fuse by 25-30 years

5→ one at tip of spinous, one at the tip of each TVP, two as ring epiphyses at upper and lower surfaces of bodies

T/F C1 has NO secondary ossification centers NBCE

True

C2 has a secondary ossification center where?

tip of the dens

Posterior arch agenesis can be _

complete or partial→ if cartilage template is present then partial

If you have a posterior arch agenesis, you may see an enlarged C2 spinous which is called _

C2 megaspinous sign

What are some additional things to look for with posterior arch agenesis?

C2 megaspinous sign

hypertrophy of the anterior tubercle

How do you determine trauma vs congenital?

congenital will have well corticated (white) borders

What is a non-union of the C1 posterior arch?

failure of fusion

aka SBO

aka Midline cleft

aka Dysraphism

cartilage of neural/posterior arches is present but the synchondrosis of the right and left posterior arch segments is faulty

margins are smooth, rounded, and corticated

What is non-union anterior arch of C1?

failure of fusion of the anterior arch RARE

What is chiari malformation?

herniation of cerebellar tonsils is over 3 mm

What is the significance of chiari malformation?

1. Wrong way scoliosis aka left thoracic scoliosis

2. Bony anomalies→ klippel-feil

3. Syrinx/syringomyelia

What is assimilation of atlas/occipitalization?

one of MC carniocervical junction anomaly

complete or partial

What is clinical significance of assimilation of atlas?

instability/basilar impression

What are some clinical signficance of assimilation of atlas?

1. Non-segmentation (blocked) of C2 and C3 is Common

2. Basilar invagination

3. Cleft palate

4. Cervical ribs

5. Urinary tract anomalies

6. Cranio-cervical instability

What are the classic features of congenital non-segmentation (block vertebra)?

1. Rudimentary disc

2. Smooth concave anterior vertebral body margins (Wasp waist)

3. Combined vertebrae are taller

4. Large foramen seen on lateral view

What is clinical significance of non-segmentation vertebra?

Non-segmentation is more accurate than fusion

MC at C5/C6, C2/C3, and L4/L5

How can you tell the difference between congenital and acquired/post-surgical block vertebra?

Congenital→ rudimentary disc, smooth concave anterior vertebral body margins, combined vertebra may be of greater height and large foramen on lateral view

Acquired→ Obliterated disc, flat/squared anterior vertebral body, no change in height, no change in foramen size

Today, most surgical fusion is performed with hardware alone or hardware with autograft, or allograft, and and not with _ alone

autograft

What is the surgery where you get a surgical fusion performed called?

COF→ anterior cervical discectomy fusion

What are multiple segmentation anomalies of cervical spine called?

Klippel-feil

What are some features of klippel-feil syndrome?

short webbed neck

low posterior hairline

reduced cervical range of motion

What are some associated conditions with klippel-feil syndrome?

1. Renal anomalies→ 50%

2. Hearing loss, possibly deafness→ 30%

3. Arnold chiari and or syringomyelina

4. Sprengel deformity→ non descended scapula (3:1 female to male)

What feature is associated with sprengel’s deformity?

omovertebra bar

What is a posterior ponticle?

arcuate foramen (ponticulus posticus) is a normal variant of atlas

calcification of the posterior atlanto-occipital membrane

can be complete or incomplete

What is the clinical significance of posterior ponticle?

possible vertebral artery occlusion with trauma related instability

What is this?

Epitransverse process→ bony extension originating from transverse process of C1 upward to the skull bone

What is the difference between epitransverse process and paracondylar process?

Epitransverse process→ variant of atlas where bony outgrowth arises from TVP and articulates with occiput

Paracondylar process→ variant of occipital bone where enlarged bony process extends caudally from paracondylar region towards TVP of atlas (can be unilateral or bilateral)

What imaging could be used for epitransverse processes to see?

CT, CBCT

What is the clinical significance of epitransverse processes?

1. May create lateral head tilt

2. may affect adjusting technique

3. effectively results in fusion of C1 to occiput

What is os terminale? (Ossiculum terminale aka bergmann ossicle)

failure of union of the secondary center of ossification found at the tip of the dens

appears at age 3-6

Not considered anomaly unless persists after age of 12

not associated with instability

Os terminale is almost always in what shape?

“V” shaped

look at cortical borders to rule out fracture

Os odontoideum is associated with what condition?

down syndrome

People with os odontoideum are at risk for _

VBAI

Os terminale is oftenly confused for _

Type 1 Dens fracture

always stable

What type of dens fracture is the most common?

Type 2 dens fracture→ heal bad

confused for os odontoideum

Type 3 fracture has the best _

prognosis

Most os odontoidium is a result of _

old un-united odontoid fracture

If a patient is stable and asymptomatic what is the treatment?

leave alone/monitor

If a patient is unstable and symptomatic, what is the treatment?

surgical referral

Castelvi classifcation is used for _

transitional segment classification

If L5 doesn’t fully segment from sacrum and looks like S1 it is called _

sacralization

If S1 doesn’t full segment rom L5 and looks like L6 it is called _

Lumbarization

What is a typical feature of lumbosacral transitional segments?

hyperplasia of transverse process→ L3 MC

occasional accessory joint degeneration→ Bertolotti’s syndrome

Spatulated TVP

Rudimentary disc space

What is bertolotti syndrome?

lumbo-sacral transitional segment with accessory bone degeneration

low back pain

Transitional segment and iliolumbar ligament calcification=

DISH unilaterally or bilaterally

What is facet tropism?

asymmetrical orientation of facet joints

common in sub axial cervical spine

coronal and sagittal facets at one level

8 degree difference side to side

highest at c2-c3 whereas lowest at c6-c7 level

common at L5-S1

What is the clinical significance of facet tropism?

Facet tropism could be predisposing factor to disc degeneration, facet degeneration, and degenerative spondylolisthesis

What is transverse process accessory articulation?

TVP grow towards eachother→ forming pseudoarticulation

What is persistent apophysis?

look for well corticated borders

DDX→ old clay shoveler fx

Apophyseal injuries occur most commonly during _

sporting activities→ MC at growth plates

What is a risser sign?

how to measure skeletal maturity

Where is most apophyseal injuries occur?

occur in pelvic region due to numerous apophyses and strength or attaching muscles

other location are tibial tuberosity, inferior patellar pole, calcaneal tuberosity, 5th metatarsal base, acromion, proximal humerus, medial epicondyle and distal radius

What is the best imaging for persistent apophysis?

X-ray

MRI→ BEST MODALITY

1. shows physeal widening without displacement

2. increased signal of the physis on fluid-sensitive sequences

3. bone marrow edema of apophysis

4. soft tissue edema

What are oppenheimer ossicles?

accessory ossicles of the facet joints

found in 4% lumbar spines

single, unilateral ossicle of the inferior articular processes

What are image findings with oppenheimer ossicles?

1. Best seen on sagittal CT

2. usually seen at L2/L3

3. Smooth corticated

4. Synovial space of adjacent facet may communicate with the cleft between the ossicle and articular process

5. Associated with neural arch malformations

What is an absent pedicle?

can be congenital agenesis or acquired destruction

Congenital→ RARE condition

Destructive→ BAD

1. Tumor→ Primary bone tumor, soft tissue tumor, secondary tumor (lytic metastasis MC)

Winking owl sign (unilateral absence of spine pedicle)

What are some items that may help differentiate congenital absence from other etiologies?

1. May have stress hypertrophy (enlargment, cortical thickening and sclerosis) or contralateral pedicle

2. May have accessory transverse process sign, small inferiorly directed transverse process with small joint like space seperates it from pedicle or vertebral body

3. May have spinous deviation sign→ deviation of spinous towards contralateral side

If you see a winking owl sign that is congenital you should assume it is _

lytic metastasis

What is Hahn vascular cleft/groove/canal?

vertebral vascular foramina

intraosseous nutrient arteries: foramen usually seen anterolaterally

basivertebral veins which can be seen on posterior surface of vertebral body in midline

What is clinical significance of developmental dysplasia of the hip (DDH)?

congenital dislocation of the hip

occurs from ligamentous laxity and abnormal position in utero

What are the risk factors for DDH?

1. Female gender

2. firstborn baby

3. family history

4. breech presentation

5. oligohydramnios

6. metatarsus adductus

7. spina bifida

What orthopedic exam is performed on infants for developmental dysplasia of the hip?

Ortolani and Barlow

What are some image findings of DDH?

left hip is more frequently affected

ULTRASOUND is the modality of choice

Alpha angle needs to be greater than 60 degrees (normal)

ultrasound is less than 50 degrees is DDH

Bony coverage is greater than 50% coverage of the femoral epiphysis by the acetabular roof is normal

What are some other lines that diagnosis DDH?

1. Hilgenreiner line

2. Perkin line

3. Shenton line

4. acetabular angle

5. extrusion index

6. center-edge angle

What is hilgenreiner’s line?

horizontal line connecting inferior aspect of tri-radiate cartilages bilaterally

What is perkin’s line?

drawn vertically through lateral aspect of acetabular roof perpendicular to Hilgenreiner’s line

ossified femoral head should be inferomedial quadrant

What is the acetabular angle?

plain film measurement used when evaluating DDH

measured between Hilgenreiner’s line and line parallel to acetabular roof

What is the measurement for acetabular angle?

Under 1= Less than 22 degrees

Adults= over 45 degrees (33-38 degrees)

What is Putti’s triad? TQ

1. Absent or small proximal femoral epiphysis

2. Superolateral/lateral displacement of femur

3. Increased acetabular angle

What is the clinical significance of DDH?

acetabular protrusion→ intrapelvic displacement of acetabulum

Primary→ developmental or post-surgical DDH

Secondary→ bone softening diseases like paget disease, psoriatic arthopathy, RA, ankylosing spondylitis

What are some image findings of DDH?

Center-edge angle (Wiberg)→ greater than 40 degrees (Kohler’s line)

Projection of the femoral head medial to the iliioischial line (acetabular protrusion)

What are femoral herniation pits?

“schmorl’s node in femoral neck”

Synovial herniation pits have no clinicial significance (LEAVE IT ALONE LESION)

seen in 5-33% of the cam form of femoral acetabular impingement FAI

“Pitt’s pit”

What is Femoral acetabular impingement? FAI

presents with hip pain secondary to mechanical impingement from abnormal hip morphology

What are the three types of FAI?

1. Pincer morphology→ overcoverage of the femoral head

2. Cam morphology→ bump formation at the femoral neck and asphericity

3. Both forms of morpholigcal changes can co-occur in a mixed type

What is accelerated with FAI?

Labral and cartilage injury→ leads to OA

What views are recommended for FAI?

frog-leg lateral

What are the possible features on imaging of FAI?

1. Cam or pincer morphology

2. Pistol grip deformity (CAM)

3. Acetabular overcoverage (PINCER)

what is this angle?

wiberg angle→ should be 25-40 degrees

if excessed 40→ Pincer type FAI

What does the alpha angle measure with FAI?

extent to which the femoral head deviates from spherical

What are the measurements for an alpha angle in hip?

Normal→ less than 50 degrees

CAM type FAI→ greater than 50 degrees

What is a ischiopubic synchondrosis?

little bump on the ischiopubic region

DDx→ fracture

What is paraglenoid sulcus?

little archs at the ASIS seen in pelvic view

DDX→ sacroilitis

What are the types of soft tissue calcification?

Dystrophic→ tissue trauma, prior infection, inflammation MC

Metabolic/metastatic→ widespread soft tissue calcification secondary to metabolic and endocrinological diseases

Physiological→ normal, within cartilaginous tissue

What is the significance of a stylohyoideus ossificaiton?

Eagle syndrome→ neck pain, neurovascular compromise

CBCT can help measure elongation adn approximation to C1

What is the differential diagnosis for costal cartilage calcification?

lung cancer

What is a falx cerebri calcification?

calcification of dura

right down middle of head (separates R and L hemispheres)

What is petroclinoid ligament calcification?

calcification of the dura

runs horizontal above eyes

What is pineal gland calcification?

les than 1.0 cm is good

50% of population has it

rare

in less than 6 years suspect pinealoma

should not exceed 10 mm

Where is thyroid cartilage calcifications seen?

C6-C7 area

vertical lines over the TVP in the AP cervical view

What is phleboliths?

calcified venous thrombi

perirectal veins (not midline)

If you see phleboliths in other areas, what does it indicate?

hemangioma/AV fistula/ malformations

What is carpal coalition?

carpal and tarsal fusion are misnomers so called (coalition)

connection between two bones without indicating the etiology

MC involved bones are hamate and triquetrum although many combinations are reported

What are the associations with multiple carpal coalitions?

ellis-van creveld syndrome

Holt oram syndrome

Arthrogryposis

Turner syndrome

symphalangism