A positional abnormality marked by outward bowing of the legs in which the knees stay wide apart when a person stands with the feet and ankles together.

The legs angle inward, such that the knees are close together and the ankles far apart.

Short (hypoplastic) phalanx of finger, affecting one or more phalanges.

Diminished length of one or more metacarpal bones in relation to the others of the same hand or to the contralateral metacarpal.

Underdeveloped acetabulae.

Delayed ossification of the femoral head.

There is normally one ossification center in the head of the femur. This term applies if there are multiple such centers.

Weakness of the hip girdle and upper thigh muscles, for instance in myopathies, leads to an instability of the pelvis on standing and walking. If the muscles extending the hip joint are affected, the posture in that joint becomes flexed and lumbar lordosis increases. The patients usually have difficulties standing up from a sitting position. Due to weakness in the gluteus medius muscle, the hip on the side of the swinging leg drops with each step (referred to as Trendelenburg sign). The gait appears waddling. The patients frequently attempt to counteract the dropping of the hip on the swinging side by bending the trunk towards the side which is in the stance phase (in the German language literature this is referred to as Duchenne sign). Similar gait patterns can be caused by orthopedic conditions when the origin and the insertion site of the gluteus medius muscle are closer to each other than normal, for instance due to a posttraumatic elevation of the trochanter or pseudarthrosis of the femoral neck.

Exaggerated anterior convexity of the thoracic vertebral column.

The presence of an abnormal lateral curvature of the spine.

An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.

A rounded, bulging chest that resembles the shape of a barrel. That is, there is an increased anteroposterior diameter and usually some degree of kyphosis.

Abnormally increased movement at the junction between the first cervical (atlas) and the second cervical (axis) vertebrae as a result of either a bony or ligamentous anomaly.

A positional abnormality marked by outward bowing of the legs in which the knees stay wide apart when a person stands with the feet and ankles together.

Irregularity of the normally smooth surface of the metaphyses.

A flattened vertebral body shape with reduced distance between the vertebral endplates.

Underdeveloped scapula.

A type of disproportionate short stature characterized by a short trunk but a average-sized limbs.

The odontoid process, or dens, is a bony projection from the axis (C2) upward into the ring of the atlas (C1) at the top of the spine. During embryogenesis, the body of the odontoid derives from the centrum of the atlas and separates from the atlas, fusing with the superior portion of the axis. If the odontoid is hypoplastic or absent, the attachments for the apical and alar ligaments are missing, allowing for excessive rotation of the atlas, craniocervical instability, and possibly cord compression (summary by Stevens et al., 2009).

An alteration of the normally smooth contour of the epiphysis leading to an irregular appearance.

Anterior tongue-like protrusions of the vertebral bodies.

Head circumference below 2 standard deviations below the mean for age and gender.