An anatomy lesson from Coach Smith, who realizes that this may provoke
another LONG discussion:

No one disputes that the 12 Cranial nerves (6 of which affect infant
suck-swallow-breathe) pass through foramina. Any college-level anatomy book
contains this information. Gray's Anatomy is both classic and excellent, and
there are many others.

The disagreement lies in the nature of these foramina and the nature of the
sutures between the cranial bones. Some of these foramen begin in the spaces
or sutures between the cranial bones, such as the jugular foramen which is
between the temporal and occipital bones. Other foramina, in the adult, are
holes through the bone, such as the hypoglossal foramen entirely within the
occipital bone.

Ossification of the cranial bones has a LOT to do with this discussion. At
birth the cranial bones are very different than they are in the adult.  All
of the cranial bones move during the birth process - therefore there is
motion along the sutures/spaces between the bones. If there were no motion
along the sutures, birth would be very difficult.  In addition, in the
infant, some of the cranial bones are in several pieces. This allows for
even more molding during birth. The pieces of an individual bone join (fuse
or ossify) before adulthood. An example is the occipital bone, which is in 4
pieces during infancy and fuses into one piece by around age 6 years.
Furthermore, some texts say the major bones fuse (or nearly fuse) by
adulthood, such as the occipital and temporal, making the foramen that began
in the sutures between those bones more stable.

The hypoglossal foramen is an example of a foramen that begins as a space
between the pieces of the occipital bone during infancy, then fuses to form
a hole through the bone by adulthood. Through it passes the hypoglossal
nerve, which controls the motor activity of the tongue.

Osteopathic and cranial-sacral research asserts, with some very good
evidence, that the sutures remain moveable even in adulthood, as long as the
person is alive. Other scientists assert that by adulthood, the skull is
fused, period.  However, I have found NO disagreement that during infancy,
the sutures do allow substantial movement and growth - hence the changing
size and shape of the infant head. This includes the spaces between the bone
pieces as well as the sutures between the bones themselves.

Linda J. Smith, BSE, FACCE, IBCLC
Bright Future Lactation Resource Centre
Dayton, OH USA
http://www.bflrc.com

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