Prognathism, also called Habsburg jaw or Habsburgs' jaw
primarily in the context of its prevalence amongst members of the
House of Habsburg
The House of Habsburg (), alternatively spelled Hapsburg in Englishgerman: Haus Habsburg, ; es, Casa de Habsburgo; hu, Habsburg család, it, Casa di Asburgo, nl, Huis van Habsburg, pl, dom Habsburgów, pt, Casa de Habsburgo, la, Domus Hab ...
,
is a positional relationship of the
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
or
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the
coronal plane
The coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes.
Details
The coronal plane is an example of a longitud ...
of the skull. In
general dentistry,
oral and maxillofacial surgery, and orthodontics, this is assessed clinically or radiographically (
cephalometrics). The word ''prognathism'' derives from Greek πρό (''pro'', meaning 'forward') and γνάθος (''gnáthos'', 'jaw'). One or more types of prognathism can result in the common condition of
malocclusion
In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855-1930), ...
, in which an individual's top
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
and lower teeth do not align properly.
Presentation
Prognathism in humans can occur due to normal variation among
phenotypes
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
. In human populations where prognathism is not the norm, it may be a malformation, the result of injury, a disease state or a hereditary condition.
Prognathism is considered a disorder only if it affects
chewing
Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...
,
speech
Speech is a human vocal communication using language. Each language uses Phonetics, phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if ...
or social function as a byproduct of severely affected aesthetics of the face.
Clinical determinants include soft tissue analysis where the clinician assesses nasolabial angle, the relationship of the soft tissue portion of the chin to the nose, and the relationship between the upper and lower lips; also used is dental arch relationship assessment such as
Angle's classification.
Cephalometric analysis is the most accurate way of determining all types of prognathism, as it includes assessments of skeletal base, occlusal plane angulation, facial height, soft tissue assessment and anterior dental angulation. Various calculations and assessments of the information in a cephalometric radiograph allow the clinician to objectively determine dental and skeletal relationships and determine a treatment plan.
Prognathism should not be confused with
micrognathism
Micrognathism is a condition where the jaw is undersized. It is also sometimes called mandibular hypoplasia. It is common in infants, but is usually self-corrected during growth, due to the jaws' increasing in size. It may be a cause of abnorma ...
, although combinations of both are found. It affects the middle third of the face, causing it to jut out, thereby increasing the facial area, similar to the phenotype of archaic hominids and other apes. Mandibular prognathism is a protrusion of the mandible, affecting the lower third of the face. Alveolar prognathism is a protrusion of that portion of the maxilla where the teeth are located, in the dental lining of the upper jaw.
Prognathism can also be used to describe ways that the maxillary and mandibular dental arches relate to one another, including malocclusion (where the upper and lower teeth do not align). When there is maxillary or alveolar prognathism which causes an alignment of the maxillary incisors significantly anterior to the lower teeth, the condition is called an
overjet
Overjet is the extent of horizontal ( anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II (division I) malocclusion the overjet is increased as the maxillary central incisors are protrud ...
. When the reverse is the case, and the lower jaw extends forward beyond the upper, the condition is referred to as
retrognathia (reverse overjet).
Classification
Alveolar prognathism
Not all alveolar prognathism is anomalous, and significant differences can be observed among different ethnicities.
Harmful habits such as
thumb sucking
Thumb sucking is a behavior found in humans, chimpanzees, captive ring-tailed lemurs, and other primates.Benjamin, Lorna S.: "The Beginning of Thumbsucking." ''Child Development'', Vol. 38, No. 4 (Dec., 1967), pp. 1065–1078. It usually involve ...
or
tongue thrust
Tongue thrust (also called reverse swallow or immature swallow) is a pseudo-pathological name of what is either considered a normal adaptive lip seal mechanism, whereby normal nasal breathing or normal swallowing can occur. Or, it is seen as an o ...
ing can result in or exaggerate an alveolar prognathism, causing teeth to misalign. Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition.
Alveolar prognathism can also easily be corrected with fixed orthodontic therapy. However, relapse is quite common, unless the cause is removed or a long-term retention is used.
Maxillary prognathism
In disease states, maxillary prognathism is associated with
Cornelia de Lange syndrome
Cornelia de Lange syndrome (CdLS) is a genetic disorder. People with this syndrome experience a range of physical, cognitive, and medical challenges ranging from mild to severe. The syndrome has a widely varied phenotype, meaning people with the sy ...
; however, so-called false maxillary prognathism, or more accurately,
retrognathism
Retrognathia is a type of malocclusion which refers to an abnormal posterior positioning of the maxilla or mandible, particularly the mandible, relative to the facial skeleton and soft tissues.
A retrognathic mandible is commonly referred to as a ...
, where there is a lack of growth of the mandible, is by far a more common condition.
Prognathism, if not extremely severe, can be treated in growing patients with orthodontic functional or orthopaedic appliances. In adult patients this condition can be corrected by means of a combined surgical/orthodontic treatment, where most of the time a mandibular advancement is performed. The same can be said for mandibular prognathism.
Mandibular prognathism (progenism)
Pathologic
mandibular
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
prognathism is a potentially disfiguring genetic disorder where the lower
jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth and serv ...
outgrows the upper, resulting in an extended
chin
The chin is the forward pointed part of the anterior mandible (List_of_human_anatomical_regions#Regions, mental region) below the lower lip. A fully developed human skull has a chin of between 0.7 cm and 1.1 cm.
Evolution
The presence of a we ...
and a
crossbite
Crossbite is a form of malocclusion where a tooth (or teeth) has a more buccal or lingual position (that is, the tooth is either closer to the cheek or to the tongue) than its corresponding antagonist tooth in the upper or lower dental arch. In o ...
. In both humans and animals, it can be the result of
inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and o ...
. In brachycephalic or flat-faced dogs, like
shih tzu
The Shih Tzu (, ; literally " Hsi Shih dog") is a toy dog breed originating from Tibet and was bred from the Pekingese and the Lhasa Apso.
Shih Tzus are known for their short snouts and large round eyes, as well as their long coat, floppy ear ...
s and
boxers, it can lead to problems such as underbite.
In humans, it results in a condition sometimes called ''lantern jaw'', reportedly derived from 15th century
horn lanterns, which had convex sides. Traits such as these were often exaggerated by inbreeding, and can be traced within specific families.
Although more common than appreciated, the best known historical example is Habsburg jaw, or Habsburg or Austrian lip, due to its prevalence in members of the
House of Habsburg
The House of Habsburg (), alternatively spelled Hapsburg in Englishgerman: Haus Habsburg, ; es, Casa de Habsburgo; hu, Habsburg család, it, Casa di Asburgo, nl, Huis van Habsburg, pl, dom Habsburgów, pt, Casa de Habsburgo, la, Domus Hab ...
, which can be traced in their portraits. The process of portrait-mapping has provided tools for
geneticist
A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic processe ...
s and
pedigree
Pedigree may refer to:
Breeding
* Pedigree chart, a document to record ancestry, used by genealogists in study of human family lines, and in selective breeding of other animals
** Pedigree, a human genealogy (ancestry chart)
** Pedigree (animal ...
analysis; most instances are considered
polygenic
A polygene is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait, thus contributing to multiple-gene inheritance (polygenic inheritance, multigenic inheritance, quantitative inheritance), a type of ...
, but a number of researchers believe that this trait is transmitted through an autosomal recessive type of inheritance.
![Berlín DHM Leopoldo I 02](https://upload.wikimedia.org/wikipedia/commons/a/ac/Berl%C3%ADn_DHM_Leopoldo_I_02.JPG)
Allegedly introduced into the family by a
member
Member may refer to:
* Military jury, referred to as "Members" in military jargon
* Element (mathematics), an object that belongs to a mathematical set
* In object-oriented programming, a member of a class
** Field (computer science), entries in ...
of the
Piast dynasty
The House of Piast was the first historical ruling dynasty of Poland. The first documented Polish monarch was Duke Mieszko I (c. 930–992). The Piasts' royal rule in Poland ended in 1370 with the death of king Casimir III the Great.
Branch ...
, it is clearly visible on family tomb sculptures in
St. John's Cathedral, Warsaw. A high propensity for politically motivated intermarriage among Habsburgs meant the dynasty was virtually unparalleled in the degree of its inbreeding.
Charles II of Spain
Charles II of Spain (''Spanish: Carlos II,'' 6 November 1661 – 1 November 1700), known as the Bewitched (''Spanish: El Hechizado''), was the last Habsburg ruler of the Spanish Empire. Best remembered for his physical disabilities and the War o ...
, who lived 1661 to 1700, is said to have had the most pronounced case of the Habsburg jaw on record, due to the high number of
consanguineous
Consanguinity ("blood relation", from Latin '' consanguinitas'') is the characteristic of having a kinship with another person (being descended from a common ancestor).
Many jurisdictions have laws prohibiting people who are related by blood fro ...
marriages in the dynasty preceding his birth.
Treatment
Prior to the development of modern dentistry, there was no treatment for this condition; those who had it simply endured it. Today, the most common treatment for mandibular prognathism is a combination of
orthodontics
Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial ...
and
orthognathic surgery
Orthognathic surgery (), also known as corrective jaw surgery or simply jaw surgery, is surgery designed to correct conditions of the jaw and lower face related to structure, growth, airway issues including sleep apnea, TMJ disorders, malocclusion ...
. The orthodontics can involve
braces, removal of teeth, or a
mouthguard
A mouthguard is a protective device for the mouth that covers the teeth and gums to prevent and reduce injury to the teeth, arches, lips and gums. An effective mouthguard is like a crash helmet for teeth and jaws. It also prevents the jaws com ...
.
In insects
In
entomology
Entomology () is the science, scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such ...
, prognathous means that the mouthparts face forwards, being at the front of the head, rather than facing downwards as in some insects.
See also
*
Dental pathology
Tooth pathology is any condition of the tooth, teeth that can be congenital or acquired. Sometimes a congenital tooth diseases are called ''tooth abnormalities''. These are among the most common diseases in humans The preventive medicine, preventi ...
Notes
References
Sources
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External links
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{{Dentofacial anomalies and jaw disease
Biological anthropology
Facial features
House of Habsburg
Jaw disorders
Paleoanthropology
pt:Prognatismo