Achondroplasia of Pelvis
1. "Champagne glass" pelvis
Normal pelvis shape - brandy snifter
2. Achondroplasia of Humerus
Rhizomelia - "short root"
*Look up other associated signs
Central canal stenosis - measurements too small (impingement on thecal sac)
Posterior scalloping (dural ectasia, CSF pulsations)
Underdeveloped ischium
Alteration at hip (valgus or varus representation)
Premature DJD
Small foramen magnum (most common lethal complication, usually die during birth)
Cleidocranial Dysostosis
Missing clavicle
Only 10% of patients will have complete agenesis of clavicle
Problems with cranial skull development (Wormian bones, cleft palate)
Shape of thoracic cage - to narrow at thoracic inlet, normal base, funnel-shaped)
Measure McGregor's line
Missing body of pubic bone
Lack of clavicle introduces a mobility of shoulder that is not normal (hypermobility of
shoulder complex)
Funnel Chest
Thoracic cage narrow at top
Marfan's Syndrome
Long, narrow feet
Arachnodactyly - spider fingers and toes (metacarpals, metatarsals, and phalanges are
longer than normal)
Ligament laxity
Thumb sign - have patient fold thumb across palm and make a fist
Marfan's patient has positive thumb sign (can see end of thumb sticking out of palm of
hand) - 2 reasons: arachnodactyly and ligament laxity
Need glasses or ocular surgery (lens dislocation)
About 50% will have scoliosis
There is a significant percentage that has pectus excavatum or pectus carinatum (chest
maldevelopment)
More lethal - connective tissue maldevelopment of aorta
Average height is over 6 feet
Absence of right heart border and shape of thoracic cage will help us determine chest
abnormality
Osteogenesis Imperfecta
Brittle bone disease
Long, thin bones or short, stumpy bones
Short bones - premature closure of growth plate (traps bone in immature dimension)
Rods in lower legs to help prevent fracture (sometimes also in femurs)
Exuberant callous formation
2 major forms:
1. Congenital - worst
2. Tarda form - discovered anytime after birth, fracture easily but not as much as
congenital form
Usually short stature
Bone that is under-mineralized
In the eye, there is blue sclera (over 90% of patients will have blue sclera)
Abnormal dentition (small, underdeveloped teeth and cavities easily develop)
Melorheostosis
Can add bone to outside but can fill-in intermedullary cavity with bone (inward or
outward dense bone)
Neurovascular compression - sensory or vascular abnormalities
Progressive
Melorheostosis
Osteopetrosis
*Brittle bone disease
Demonstrate a failure of reabsorption of fetal embryonic bone
May have infections due to decreased marrow so decreased WBC
Usually see tarda form
May change the way we treat these patients
Later we find it the less the severe the presentation
May affect few or many bones
Rugger jersey spine - alternating bands in spine, black, white, black, white, etc. (also
called sandwich vertebra)
Rugger jersey spine
Osteopetrosis in a 46-year-old man.
Abnormal bone can break and fracture plane can persist for a long time
Bone within a bone appearance
Increased density on plain film will not appear on bone scan
2 Categories:
1. Familial
2. Tarda - most common
Anemia is usually present
Osteopoikilosis
Multiple dense spots
No associated complaints
Age range is 3-73
Asymptomatic
Typically incidental finding
No malignant degeneration or lab findings
MRI presentation is not normal
Does not make bone weaker
Osteopoikilosis
Progressive Diaphyseal Dysplasia
Intrusion into medullary cavity
Distortion of cortical medullary junction
Progressive
Only involves diaphysis
Piknodysostosis
*Brittle bone disease
No frontal sinus
Large head
No mastoid air cells
Maxillary sinus not well developed
Patient has lost teeth
Obtuse angle of mandible
10% will have mental retardation
Elfin features - craniofacial discrepancies
Shepard's crook deformity - extensive involvement of proximal femur that results in a
characteristic varus deformity which resembles a shepard's crook;
Acroosteolysis - breaking of bones in hands and feet
Mucopolysaccharide Dysplasia
8 different types
1. Type I Hurler's - Gargoylism
Change in skull, positioning of eye
Hypertelerism
Depressed nasal bridge
Looked normal at birth
Over the next year to year and half the abnormalities develop
1 out 100,000 births
Testing in utero
Difference from achondroplasia is that achondroplasia is identifiable at birth
Inferior or superior beaking of vertebra
2. Type IV Murquios
Protruding sternum
Lab keratosulfaturia present in urine
Look normal at birth
Short stature (average 4 feet)
*Middle beaking of vertebra
*Tendency to have underdeveloped odontoid (odontoid hypoplasia)
Murquios: Middle beaking of vertebra
Spondyloepiphysial Dysplasia
Hump (heaped-up) vertebra
Along endplates
Failure for ring apophysis to mature correctly
Anomalies
Occipitalization of the Atlas
"Guess what did NOT happen on the way to the "formation" of the spine?"
Typically, the anterior arch of the atlas is fused to the skull base
–one half of patients with occipitalization of the atlas also have vertebral fusion at the C2-C3 spinal
level
–although the odontoid process is high, directly beneath the foramen magnum basilar impression is
uncommon
Significance
–is a normal variant that is asymptomatic in most cases
–hypermobiliy at the ADI
Os Odontoideum
Overall considered uncommon
Ununited ossification centers
Long-standing non-union fracture
Can be absent
Significance
–renders the transverse atlantal ligament
incompetent
–potential for significant neurological insult from trivial trauma. High velocity adjusting
contraindicated.
Patient may not know
Doctor probably should suspect an abnormality
Not recent
Atlanto-axial instability
Sub-occipital muscle spasm and headaches
VBAI
Wedge-shaped ADI
Boney structures have not fully developed
Ligaments are more lax
Failure of Segmentation AKA Block Vertebra
Embryological failure of sclerotome segmentation and separation first described by
Macalister in 1893
Fusing of Vertebral Bodies
Causes:
Trauma
Inflammatory arthritides: psoriasis, Rheumatoid arthritis, etc.
Congenital
Infection
Wasp waist appearance
Rudimentary disc - very common
No facet joint
Anterior and posterior fusion - typical
Losing motion
Should perform flexion/extension views to assess ADI
Higher the block the more common the complication
Most common complication is DJD
Higher the block the more strongly it is associated with ADI instability
Sprengels Deformity
Unilateral elevation of scapula
Sometimes presents with omovertebral bone (spine to spine bone bridge) - usually
presents 45% of the time
Scapula fail to descend
Winking Owl Sign
Appears as if there is no pedicle on plain film
On CT scan, there is evidence of pedicle
Most common cause of this is lytic metastasis
On CT scan, the other pedicle is very dense because doing the work for both pedicles
Best described as hypoplastic pedicle
Can determine if problem congenital or lytic metastasis based on other pedicle (if bright
white (more dense) then congenital)
This can occur in other regions (L5/S!) but not called winking owl syndrome because
there are not true pedicles in sacral region
Variant of Hemivertebra
Growth center did not completely develop
One side of vertebra higher than other side
Produces a structural convexity
Butterfly Vertebra
Superior endplate of one vertebra and inferior endplate of next vertebra did not form
Triangular-shaped
Spina Bifida Oculta
Spinous process does not develop
No clinical significance
Might palpate as defect
Beaked Vertebra
Limbus variant
Anterior part of lumbar vertebra dips down
Cupid's Bow
Biconcave endplate
Notochordal persistency
Very common at L5
On CT scan, the inclusion of nucleus pulposus on endplate – Nuclear impression
Series of Hemivertebrae
Structural scoliosis
"Scrambled" spine
Knife-Clasp Deformity
Translocation of growth center
Blade-like spinous process
Can cause back and leg pain
Pain on extension
Hypoplasia of posterior arch
Hypoplasia of Posterior Tubercle of C1
Short posterior arch of C1
Spinolaminar line not in alignment (posterior tubercle is further inward)
Have to rule out ADI space and Os Odontoideum
Elongation of Posterior Tubercle and Elongation Between Posterior Cervical Body
and Spinolaminar Line of C2 Body
Both are normal variations
Posterior Ponticle
A.k.a. arcuate foramen, Kimmerly anomaly, posticus ponticus
Calcific bridge between the lateral mass and posterior tubercle
In 15% of the population
Proper testing for VBAI is recommended (George's test, etc.)
Approximately 10% of the patients with arcuate foramen demonstrate signs and
symptoms
Significance
–minimal clinical significance or risk
–question of vertebral artery occlusion
Agenesis of posterior tubercle
No spinolaminar line on posterior tubercle
Stress hypertrophy
Failure in segmentation
Agenesis of posterior arch of C1
Posterior Arch Maldevelopment at L5
Associated with spina bifida oculta
Underdevelopment of Pars Interarticularis
Neck of Scotty dog extremely thin
No contact sports because could cause fracture
Spondylolitic Spondylolisthesis - Anterolisthesis
Look at Myerding's scale and Ullman's line
Slippage of the L5 body anterior on sacral base
Most reliable way to make sure this does not change overtime is to use the percentage
method
Surgical stabilization could be an option (more than 3mm of translation)
Etiology is trauma, congenital, stress fracture (obesity, constant loading), pathology
(metastasis), or elongated pars (fracture that healed longer)
Stress fracture is the most common etiology
Degenerative is the second most common etiology
Average age of onset of a stress fracture is 18 months old
*3 mm or more of translation in considered unstable*
1. Grade I Spondylolisthesis of L5 on S1
2. Bilateral Pars Fracture of L5
Ununited Growth Centers on Tips of T1
Hypoplastic Rib
Under-developed
Intrathoracic Rib
Coming off vertebral body but not wrapping around thoracic cage
Actually goes through lung field
Patient usually does not present with any signs or symptoms
Fused Rib
2 rib heads articulating together - conjoined rib head
Might have problems with chest expansion in that area
C7
Transverse processes go down and out
T1
Transverse processes go up and out
Cervical Rib
If it has an accessory articulation then it is known as cervical digit
Linked with thoracic cage
Cervicothoracic Transitional Segment
No joint space - hypertrophic transverse process on one side
Cervical rib on other side (joint space was visible)
Rib Cartilage
Costochondral calcification
No increased serum calcium levels
Physiological calcification
Hip DJD (young patient)
Decreased joint space
Congenital hypoplasia of the acetabulum
Underdevelopment of the acetabulum can cause wear and tear and early DJD
23-year-old female with congenital hip hypoplasia.
Pseudotumor of the Pelvis
Growth center and as bone matures it disappears
Bilateral and symmetrical
On inferior ramus
Coxa Valga
Measure femoral neck angles
More than 130 degrees
Children usually in valgus range
Congenital Hypoplasia of Ischium and Pubis
Underdevelopment
Pectus Excavatum (Funnel Chest)
Heart displaced to left
Thoracic ribs steeper than normal
Reduced AP diameter
Sacral Agenesis
No sacrum
L5 articulates directly with the ilium
Bipartate Sesamoid
2 sesamoid bones on big toe
May be bilateral but will not be symmetrical
Supracondylar Process
Bone projection
Might be confused with osteochondroma (benign tumor)
Always on humerus and always points to elbow
Single projection
Osteochodroma
Consists of bone and cartilage (mixed density) - benign
On many bones
When they are on long bones, they point away from joint
Does not have ligamentous attachment
Madelung Deformity
Occurs in wrist
Carpals are not aligned
Polydactyly
More than normal amount of digits
Can occur with fingers or toes
Apert's
Mitten hand - glove hand
Malformation of the skull
Brachicephaly - skull taller than normal and thinner than normal in A-P view - coronal
sutures closed too early
Scaphocephaly - long, narrow - "boat head" - midsagittal suture does not grow normally
Lumbosacral Transitional Segments
Sacralization
Lumbarization
Type Ia - single TP that is taller than 19mm
Type Ib - pair of TP's that are both taller than 19mm
Clinically Significant Transitional Segments:
1. Type IIa - single accessory articulation, disc at transitional level has high rate of disc
herniation, also disc at above level
2. Type IIb - pair of joint articulations, also has high rate of disc herniation (not as high as
Type IIa), also disc at above level
Type IIIa - bone bar - partial sacralization, no intersegmental motion, cannot exert any
force on the disc
Type IIIb - full sacralization, pair of bone bars, no motion
Type IV - accessory joint on one side and bone bar on the other side - bone bar will
trump the joint - bone bar produces fixation