Skull bossing is a descriptive term in medical physical examination indicating a protuberance of the skull, most often in the

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

s of the forehead ("frontal bossing"). Although prominence of the skull bones may be normal, skull bossing may be associated with certain medical conditions, including nutritional, metabolic, hormonal, and hematologic disorders.

Frontal bossing

Frontal bossing is the development of an unusually pronounced forehead which may also be associated with a heavier than normal brow ridge. It is caused by enlargement of the

, often in conjunction with abnormal enlargement of other

facial bones The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull. The remainder of the skull is the neurocranium. In human anatomy and development, the facial skeleton is sometimes called the ''membranous viscer ...

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

, and bones of the hands and feet. Frontal bossing may be seen in a few rare medical syndromes such as

acromegaly Acromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There ...

– a chronic medical disorder in which the

anterior pituitary The anterior pituitary (also called the adenohypophysis or pars anterior) is a major Organ (anatomy), organ of the endocrine system. The anterior pituitary is the glandular, Anatomical terms of location#Usage in human anatomy, anterior lobe that t ...

gland produces excess

growth hormone Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...

(GH). Frontal bossing may also occur in diseases resulting in chronic anemia, where there is increased

hematopoiesis Haematopoiesis (; ; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult human, roughly ten ...

and enlargement of the medullary cavities of the skull.

Associated medical disorders

Rickets Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...

Achondroplasia Achondroplasia is a genetic disorder with an autosomal dominant pattern of inheritance whose primary feature is dwarfism. It is the most common cause of dwarfism and affects about 1 in 27,500 people. In those with the condition, the Rhizomeli ...

Acromegaly Acromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There ...

* Basal cell nevus syndrome *

Congenital syphilis Congenital syphilis is syphilis that occurs when a mother with untreated syphilis passes the infection to her baby during pregnancy or at childbirth, birth. It may present in the fetus, infant, or later. Clinical features vary and differ between ...

Cleidocranial dysostosis Cleidocranial dysostosis (CCD), also called cleidocranial dysplasia, is a congenital disorder, birth defect that mostly affects the bones and teeth. The collarbones are typically either poorly developed or absent, which allows the shoulders to be ...

Crouzon syndrome Crouzon syndrome is an autosomal dominant genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Because the branchia ...

* Cryopyrin-Associated Periodic Syndrome (CAPS – PFS) *

Ectodermal dysplasia Ectodermal Dysplasia (ED) refers to a group of genetic disorders characterized by the abnormal development or function of two or more structures that originate from the ectoderm, the outer layer of an embryo. These structures include hair, teeth ...

Extramedullary hematopoiesis Extramedullary hematopoiesis (EMH or sometimes EH) refers to hematopoiesis occurring outside of the medulla of the bone (bone marrow). It can be physiologic or pathologic. Physiologic EMH occurs during embryonic and fetal development; during this ...

Fragile X syndrome Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder. The average IQ in males with FXS is under 55, while affected females tend to be in the borderline to normal range, typically around 70–85. Physical features may include a lo ...

Hurler syndrome Hurler syndrome, also known as mucopolysaccharidosis Type IH (MPS-IH), Hurler's disease, and formerly gargoylism, is a genetic disorder that results in the buildup of large sugar molecules called glycosaminoglycans (GAGs) in lysosomes. The inabil ...

* Osteopathia Striata with Cranial Sclerosis *

Pfeiffer syndrome Pfeiffer syndrome is a rare genetic disorder, characterized by the premature fusion of certain bones of the human skull, skull (craniosynostosis), which affects the shape of the head and face. The syndrome includes abnormalities of the hands an ...

* Rubinstein-Taybi syndrome * Russell-Silver syndrome (Russell-Silver dwarf) *

Thanatophoric dysplasia Thanatophoric dysplasia is a severe skeleton, skeletal disorder characterized by a disproportionately small Rib cage, ribcage, extremely short limbs and folds of extra skin on the arms and legs. Symptoms and signs Infants with this condition hav ...

* Talfan syndrome *

Trimethadione Trimethadione (Tridione) is an oxazolidinedione anticonvulsant. It is most commonly used to treat epileptic conditions that are resistant to other treatments. It is primarily effective in treating absence seizures, but can also be used in ref ...

(antiseizure drug) use during pregnancy *

Beta-thalassemia Beta-thalassemia (β-thalassemia) is an inherited blood disorder, a form of thalassemia resulting in variable outcomes ranging from clinically asymptomatic to severe anemia individuals. It is caused by reduced or absent synthesis of the beta ...

(due to expansion of bone marrow secondary to increased

; see

)Bope, Edward T., and Rick D. Kellerman. "Chapter 13 – Hematology." ''Conn's Current Therapy: Latest Approved Methods of Treatment for the Practicing Physician''. Philadelphia: Saunders Elsevier, 2012. * Hallermann-Streiff syndrome

References

{{Reflist Medical terminology