Skull bossing

Skull bossing is when the bones of the skull become bigger than normal. It most often occurs in the frontal bones beneath the forehead. Skull bossing may happen from different medical conditions.M. Sperling: Pediatric Endocrinology. p.748 Saunders; 3 edition (2008) 

Frontal bossing
Frontal bossing is when the forehead becomes bigger than normal which may also make the brow ridge (eyebrow part of the face) stick out more. It happens when the frontal bone becomes bigger because of a medical condition. This often happens when other facial bones of the skull become bigger too, as well as the jaw bone and the bones in the hands and feet. Frontal bossing is usually seen in a few rare medical syndromes such as acromegaly - a chronic medical disorder in which the anterior pituitary  gland makes to much growth hormone (GH).PubMed Health: Frontal bossing

Turricephaly
Turricephaly often called "tower skull", may be caused by different medical conditions. In some cases such as Apert and Pfeiffer syndromes, it is caused when sutures in the skull close before they are supposed to.The Cambridge Encyclopedia of Human Paleopathology. Arthur C. Aufderheide, Conrado Rodriguez-Martin. Cambridge University Press; 1 edition (1998) p.52 

Turricephaly is also one of the most common problems which affect the bones of the face and skull in those with Sickle-cell disease.Craniofacial bone abnormalities and malocclusion in individuals with sickle cell anemia: a critical review of the literature. Costa CP1, de Carvalho HL, Thomaz EB, Sousa Sde F. Rev Bras Hematol Hemoter. 2012;34(1):60-3. doi: 10.5581/1516-8484.20120016.  2012;34(1):60-3. doi: 10.5581/1516-8484.20120016.
PMID 23049386

Medical disorders that may cause skull bossing
Acromegaly
Basal cell nevus syndrome
Congenital syphilis
Cleidocranial dysostosis
Crouzon syndrome
Hurler syndrome
Pfeiffer syndrome
Rubinstein-Taybi syndrome
Russell-Silver syndrome (Russell-Silver dwarf)
Sickle-cell disease
Trimethadione (antiseizure drug) use during pregnancy
Beta-thalassemia (due to expansion of bone marrow secondary to increased hematopoiesis)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.

References

Category:Diseases and disorders of bones
Category:Head (body part)