Step deformity is a skeletal deformity in which 2 adjacent bones which should be aligned with each other are displaced and are at different levels – resembling a step of a staircase
Examples:

Step deformity of spine

two adjacent vertebra are at different levels
can be identified by palpating the spinous process
spinous process appears prominent due to anterior/posterior displacement of adjacent vertebra (spondylolisthesis)

Step defromity of infraorbital ridge

seen in zygomatic bone (tripod fracture)

Step deformity of knee

seen in rupture of cruciate ligaments
results in displacement of tibia and fibula relative to femur

Step deformity below acromion

seen  in separation …

Blount’s disease is a growth disorder of the tibia characterised by bowing of legs
Also called pathologic tibia vara, non rachitic bowlegs, Blount Barber disease
Clinical features

Presents with progressive bowing of legs in a child
There is varus angulation and internal rotation of tibia
Usually seen in children if African origin
Associated with obesity, early walking and short stature

Clinical types

Infantile – early onset (<3 years of age)
Juvenile – 4-10 years
Adolescent – >11 years

Pathology

There is disordered bone ossification in the medial part of proximal tibial epiphysis, physis and metaphysis
Presumed to be caused by excessive compressional forces on the …

KAFO stands for :

Knee Ankle Foot Orthosis (used in orthopedics)

Orthopedic Trauma Association

Anterior wedge compression fracture of vertebra
(Click on  image for an enlarged view)

Compression fracture of the anterior part of vertebral body occurring in forward flexion
Usually does not produce neurological deficits
It is a stable fracture as only the anterior column of spine is involved
Caused by : Road traffic accidents, Fall from height
Predisposing factors : Osteoporosis

Stable spine is one which after the initial injury does not get displaced further. The spine is stable when atleast 2 columns of the spine are intact. According to the three column concept, the spine is considered to have 3 columns:

* Anterior
* Middle
* Posterior

Bones of the hand
(Click on  image for an enlarged view)
Swan neck deformity refers to a structural deformity of the hand in which

proximal interphalangeal joints are in hyperextension
distal interphalangeal joints are in hyperflexion

Commonly seen in injuries or inflammatory conditions like rheumatoid arthritis
Seen in 50% of patients with rheumatoid arthritis

Treatment is by surgical correction

Fracture of a bone in which the fracture fragments do not separate

Refers to biconcave vertebral bodies seen in osteomalacia
Similar appearance can also be seen in osteoporosis

External links:

“Fish” or “Fish Mouth” Vertebrae? – American Journal of Roentgenology

Plain x-ray pelvis AP view showing undisplaced fracture of inferior ramus of pubis.
(Click on the image for an enlarged view)
Differential diagnosis

Looser’s zone seen in osteomalacia