<P> A tooth is the toughest known substance in the body exceeding bones in density and strength . Tooth enamel lends great strength to the tooth structure . The formation of a developing tooth includes the process of dentin formation, (see: Dentinogenesis) and enamel formation, (see: amelogenesis). The tooth breaks through the gum into the mouth in a process called eruption . The formation of teeth begins in early fetal development and goes through six stages: </P> <Ul> <Li> (1) initiation stage, 6th - 7th week </Li> <Li> (2) bud stage, 8th wk </Li> <Li> (3) cap stage, 9th - 10 wk </Li> <Li> (4) bell stage, 11th - 12th wk </Li> <Li> (5) apposition </Li> <Li> (6) maturation stage </Li> </Ul> <Li> (1) initiation stage, 6th - 7th week </Li> <Li> (2) bud stage, 8th wk </Li>

Where do the neck muscles attach to the skull