Features of the newborn skull structure
Aspect ratio of parts of the skull with newborn length and weight of his body other than an adult. Baby's skull is much larger and the bones of the skull are separated. The spaces between the bones are filled with layers of connective tissue or cartilage neokostenevshego. Cranial size substantially predominates over the facial. If an adult ratio of the facial skull to the brain is approximately 1: 2, then the newborn is a ratio of 1: 8.
The main distinguishing feature is the presence of neonatal cranial fontanelles. Fontanels - it neokostenevshie parts of the membranous skull (desmocranium), which are located in areas of future joint formation.
In the early stages of fetal development calvarium is membranous formation that covers the brain. At the 2-3rd month, skipping the stage of cartilage, bone-forming nucleus, which subsequently merged with each other and form a bony plates, that is the basis of skeletal bones of the skull roof. By the time of birth between formed bone preserved sections of narrow lanes and wider spaces - fontanels. It is through these sections of the membranous skull that can sink and bulge, there is a significant shift of the skull bones themselves, allowing the passage of the head of the fetus through the narrow places of the birth canal.
The front, or large fontanelle (fonticulus anterior) has a diamond shape and is located at the junction of the frontal and parietal bones. He completely ossified by age 2. Rear, or small, fontanelle (fonticulus posterior) is located between the occipital and parietal bones. It ossifies already on the 2-3rd month after birth. Sphenoid fontanelle (fonticulus sphenoidalis) pair, located in the anterior lateral surfaces of the skull between the frontal, parietal, sphenoid and temporal bones. It ossifies almost immediately after birth. Mastoid fontanelle (fonticulus mastoideus) pair, located posterior to the wedge, at the junction of the occipital, parietal and temporal bones. Ossifies at the same time with the wedge.
|In Fig. 89.
A - lateral view;
B - top view:
1 - large fontanelle;
2 - small fontanelle;
3 - wedge-shaped fontanelle;
4 - mastoid fontanelle
a., aa. — arteria, arteriae (artery, the artery)
lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)
m., mm. — musculus, musculi (muscle, the muscle)
n., nn. — nervus, nervi (nerve, the nerve)
r., rr. — ramus, rami (branch)
s. — seu (or)
v., vv. — vena, venae (vienna)