Suture

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Sketch of two human skulls, each with a view of the vertex:
1 coronal suture ( sutura coronalis )
2 arrow suture ( sutura sagittalis )
3 lambda suture ( sutura lambdoidea )
Drawing of a human skull in side view with the designation of all skull sutures
Side view of the skull of a male elk with the designation of the individual skull bones. The clearly pronounced sutures show that the animal was probably still relatively young.

The suture ( Latin sutura , bone seam ) is the connective tissue seam between two skull bones . It is one of the fake joints .

Sutures of the skull

A distinction is made between the following main sutures in the human skull (cranium) :

  • Coronal suture (also parietal suture ) (Sutura coronalis): between the frontal bone (Os frontale) and the parietal bone (Os parietale)
  • Lambda suture (Sutura lambdoidea): between the parietal bone (Os parietale) and occiput (Os occipitale)
  • Arrow suture (Sutura sagittalis): between both parietal bones (Ossa parietalia)
  • End seam (frontal suture) between the two end legs (bones frontalia)

The other 29 sutures are systematically named after the adjacent bones, e.g. B. Sutura temporozygomatica between the temporal and zygomatic bones.

Classification according to the shape

A distinction is made according to the shape of the connecting surfaces of the adjacent bone plates:

  • Smooth seam ( Sutura plana ): The bones lie flat against each other. Example: Sutura zygomaticomaxillaris
  • Groove seam ( Schindylesis , cleavage): The bone plate of one bone engages in a groove in the other. Example: perpendicular lamina of the sphenoid bone
  • Cuticle suture ( Sutura squamosa ): The ends of the bones are beveled and overlap. Example: Sutura temporoparietalis
  • Serrated suture ( Sutura serrata ): The bones are interlocked. Example: Sutura coronalis.

Ossification of the sutures

During embryonic and fetal development , the cranial bones grow radially under the skin starting from ossification centers. At the time of birth, this growth process is not yet fully completed, so that the large flat bones of the skull roof are flexibly connected to each other via flat areas of connective tissue , the so-called fontanelles , and can be moved against each other. This allows the head to adapt to the narrowness of the birth canal during childbirth by deforming it slightly. The deformation disappears after a few days. During the first two years of life, the skull bones continue to grow and the fontanelles close. In adults, the sutures become increasingly ossified, so that the skull bones are finally firmly connected to one another by bone tissue ( synostosis ).

An unusual ossification of the cranial sutures can lead to a change in the shape of the head and B. to microcephalus , trigonocephalus , dolichocephalus , turricephalus , macrocephaly , plagiocephaly or scaphocephalus .

Premature ossification is also found in the context of syndromes , such as Muenke's syndrome or Crouzon's syndrome .

literature

  • Dieter Sasse: Compact textbook anatomy . Vol. 1 General Anatomy . Schattauer, 2004, p. 172.
  • Adolf Faller : The human body. Georg Thieme, Stuttgart 1980, ISBN 3-13-329709-0 .