This maybe because a posterior placing of the condylar head with regard to the skull or to a steep mandibular angle resulting in an evident jaw retrusion. The acquired type of micrognathia occurs after birth and usually is an effect of a disturbance to temporomandibular joint. Growth of mandible depends on the normally developing condyles and the muscle function For example, trauma or infection that affect mastoid, middle ear or the joint will result in ankylosis of temporomandibular joint leading to mandibular micrognathia. MacronagthiaMacronagthia is a condition of abnormally large jaws. The jaw size is usually proportion to the increase in skeleton size. It is usually due to excessive growth of the mandible and can have features including reverse maxillary to mandibular relationship, reverse overjet or absence of overbite. It can also be clinically presented when the glenoid fossa and condylar head is more anteriorly placed, causing mandibular prognathism. Macronagthism can be associated with other medical conditions :-
1. Pagets disease where there is overgrowth of the maxilla, cranium and mandible2. Acromegaly, an endocrine disease, can present with enlargement of bones with growth potential such as the mandible, thickened soft tissues and facial features and spade-like hands 
Macrogenia or MicrogeniaMacrogenia and microgenia occur when there is a normal skeletal relationship but the chin, skeletal and soft tissue components, failed to develop in proportion to the skeletal base, resulting in marked protrusive (macrogenia) or retrusive (microgenia) facial profile.
This allows for an accurate assessment of the size, position, orientation, shape, and symmetry of the jaws. The anterior-posterior skeletal pattern measures the relationship of the lower jaw to the upper jaw. This is judged with the patient seated upright, head in a neutral horizontal position, and teeth in gentle occlusion. It can be classified into the following classes:

Class I: The ideal relationship whereby the upper jaw lies 2-4mm in front of the lower jaw 
Class II: Upper jaw lies more than 4mm in front of the lower jaw
Class III: Upper jaw lies less than 2mm in front of the lower jaw, or in more severe cases, the lower jaw may be in front of the upper jaw. The vertical dimension can be measured by facial thirds, with ideal facial aesthetics showing equality between each vertical third. The face is divided into thirds – hairline to glabella; glabella to subnasale; and subnasale to the lowest part of the chin. Two other clinical indicators can be assessed when analysing vertical dimensions, namely the Frankfort Mandibular Planes Angle (FMPA) and the Lower Facial Height (LFH) – both of which are each recorded as either average, increased, or decreased. FMPA: This is estimated by the point of intersection between the lower border of the mandible and the Frankfort Horizontal plane. LFH: The face is divided into thirds, and the proportion of the lower third of the face is compared to the rest.The transverse relationship is a measure of jaw or facial asymmetry.