Neer classification divides lesions of the rotator cuff into three stages that typically succeed in this order during one's life.

This multidisciplinary concensus was adopted in 2001 by both the American Thoracic Society (ATS) and the European Respiratory Society (ERS) in order to standardize classification of the idiopathic interstitial pneumonias.

Hydronephrosis in infants is divided into five grades that were standardized by the Society of Fetal Urology. The grading is usually based on ultrasound, ev. intravenous urography.
 

Hydronephrosis is commonly divided into four grades according to dilation of the pelvicalyceal system and cortical thinning that can be visualised on ultrasound, CT and MRI.
 

The Hounsfield scale of tissue density is based on two values: air as -1000HU (minimum HU value) and water as 0HU. Density of other tissues is related to this range, usually from -1000 to +1000HU (-1024 to 1024 or 3072 depending on the coding of particular vendor). However, the scale by its the definition is open-ended.
 

The classification of fractures of axis was introduced by Effendi et al. and later modified by Lewine and Edwards. With further two types added (IA and IIA), the modified classification has five types.

The Young-Burgess classification system divides pelvic fracture by the direction of the force involved into three basic types - anteroposterior compression (APC), lateral compression (LC), and vertical shear (VC). First two types have three subgroups with increasing degree of severity of the injury

The original Tile classification divides pelvic fractures into three basic types according to stability based on the integrity of the posterior sacroiliac complex. It also takes into consideration the force involved. In type A, the fracture does not involve the posterior arch. Type B fracture is a result of rotational forces that cause partial disruption of the posterior sacroiliac complex. Complete disruption of the posterior complex (including the sacrospinous and sacrotuberous ligaments) occurs in type C fractures, that are both rotationally and vertically unstable.

The modified Tile AO Müller classification, like the original, divides pelvic fractures into three basic types according to stability based on the integrity of the posterior sacroiliac complex. It takes into consideration the direction of the force involved. In type A, the fracture does not involve the posterior arch. Type B fracture is a result of rotational forces that cause partial disruption of the posterior sacroiliac complex.

Le Fort classification divides fractures of the midface skeleton into three basic types according to the location of the fracture plane. However, most fractures are too complex to fit exactly one of the types.