The bones of the skull are connected to each other by continuous fibrous (sometimes cartilaginous) joints. That means that there is not cavity in the structure of these joints, and the bones are held together with dense fibrous connective tissue (or, in case of synchondroses, with cartilaginous tissue).

The exception is the joint connecting the temporal bone and the mandible, which is a temporomandibular joint.

Let’s learn about the fibrous joints, namely sutures (suturae).

Depending on the shape of the edges, the sutures can be serrate (sut. serrata), plane (sut. plana) and squamous (sut. squamosa). The largest and most noticeable sutures are:

• The sagittal suture (sut. sagittalis), which connects the medial borders of the parietal bones.

  

• The coronal suture (sut. coronalis), which connects the posterior border of the frontal bone with the anterior border of the parietal bone.

  

  

• The lambdoid suture (sut. lambdoidea), which connects the occipital margin of the parietal bone and the squamous part of the occipital bone.

  

  

• The squamous suture (sut. squamosa), which connects the squamous part of the temporal bone with the parietal bone and the greater wing of the sphenoidal bone.

  

  The rest of the sutures are less noticeable and in their name reflect the bones they connect:

  Title	Connections
  Occipitomastoid suture (sut. occipitomastoidea)	Connects the mastoid process of the temporal bone with the squamous part of the occipital bone
  Parietomastoid suture (sut. parietomastoidea)	Connects the mastoid angle of the parietal bone and the parietal notch of the squamous part, and the mastoid process of the temporal bone
  Sphenoparietal suture (sut. sphenoparietalis)	Connects the sphenoidal angle of the parietal bone and the parietal margin of the sphenoid bone
  Phenofrontal suture (sut. sphenofrontalis)	Connects the frontal edge of the greater and lesser wings of the sphenoidal bone and the orbital part of the frontal bone
  Spenosquamous suture (sut. sphenosquamosa)	Connects the squamous margin of the greater wing of the sphenoid bone with the spenoidal margin of the squamous part of the temporal bone
  Spheno-ethmoidal suture (sut. sphenoethmoidalis)	Connects the sphenoidal crest of the sphenoidal bone and the posterior border of the perpendicular plate of the ethmoidal bone
  Sphenovomerine suture (sut. sphenovomeralis)	Connects the inferior surface of the sphenoidal body and rostrum and the sphenoidal margin of the squamous part of the temporal bone
  Sphenozygomatic suture (sut. sphenozygomatica)	Connects the zygomatic margin of the greater wing of the sphenoidal bone and the frontal process of the zygomatic bone
  Frontonasal suture (sut. frontonasalis)	Connects the nasal margin of the frontal bone and the superior margin of the nasal bones
  Fronto-ethmoidal suture (sut. frontoethmoidalis)	Connects the orbital and nasal parts of the frontal bone and the corresponding margins of the ethmoidal bone
  Frontomaxillary suture (sut. frontomaxillaris)	Connects the nasal part of the frontal bone and the frontal process of the maxilla
  Frontolacrimal suture (sut. frontolacrimalis)	Connects the orbital part of the frontal bone and the superior process of the zygomatic bone
  Frontozygomatic suture (sut. frontozygomatica)	Connects the zygomatic process of the frontal bone and the frontal process of the zygomatic bone
  Zygomaticomaxillary suture (sut. zygomaticomaxillaris)	Connects the zygomatic bone and the zygomatic process of the maxilla
  Ethmoidomaxillary suture (sut. ethmoidomaxillaris)	Connects the inferior border of the orbital plate of the ethmoidal bone and the orbital surface of the body of the maxilla
  Ethmoidolacrimal suture (sut. ethmoidolacrimalis)	Connects the orbital plate of the ethmoidal bone and the lacrimal bone
  Temporozygomatic suture (sut. temporozygomatica)	Connects the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
  Internasal suture (sut. internasalis)	Connects the medial borders of the nasal bones facing each other
  Nasomaxillary suture (sut. nasomaxillaris)	Connects the lateral margin of the nasal bone and the frontal process of the maxilla
  Lacrimomaxillary suture (sut. lacrimomaxillaris)	Connects the inferior border of the lacrimal bone and the orbital surface of the maxilla
  Lacrimoconchal suture (sut. lacrimoconchalis)	Connects the inferior border of the lacrimal bone and the lacrimal process of the inferior nasal concha
  Intermaxillary suture (sut. intermaxillaris)	Connects the alveolar processes of both maxillary bones
  Palatomaxillary suture (sut. palatomaxillaris)	Connects the orbital margin of the palatine bone and the posterior border of the orbital plate of the ethmoidal bone
  Palato-ethmoidal suture (sut. palatoethmoidalis)	Connects the orbital margin of the palatine bone and the posterior border of the orbital plate of the ethmoid bone
  Median palatine suture (sut. palatina mediana)	Connects the medial border of the palatine processes of both maxillary bones, as well as the medial borders of the horizontal plates of both palatine bones
  Transverse palatine suture (sut. palatina transversa)	Connects the posterior border of the palatine processes of both maxillary bones with the anterior borders of the horizontal plates of both palatine bones

  In the area of the facial skeleton, the sutures have a more even or flat appearance. Such sutures are also called harmonious.

  The cranial cartilaginous joints (or synchondroses) are located at the base of skull. They are formed by fibrous cartilage tissue. In most synchondroses, the cartilage layer between the bones persists only until a certain age, after which the cartilage is replaced by bone tissue and synchondrosis turns into synostosis.

• The spheno-occipital synchondrosis (synchondrosis sphenooccipitalis), which connects the posterior surface of the body of the sphenoidal bone and the basilar part of the occipital bone.

• The sphenopetrosal synchondrosis (synchondrosis sphenopetrosa), which connects the body of the sphenoid bonewith the petrous part of the temporal bone.

• The petro-occipital synchondrosis (synchondrosis petrooccipitalis), which connects the posterior border of the petrous part of the temporal bone and the external borders of the basilar and lateral parts of the occipital bone.

Dictionary

Joints of the skull

Occipitomastoid suture

sutura occipitomastoidea

Parietomastoid suture

sutura parietomastoidea

Sphenoparietal suture

sutura sphenoparietalis

Sphenofrontal suture

sutura sphenofrontalis

Sphenosquamous suture

sutura sphenosquamosa

Spheno-ethmoidal suture

sutura sphenoethmoidalis

Sphenovomerine suture

sutura sphenovomeralis

Sphenozygomatic suture

sutura sphenozygomatica

Frontonasal suture

sutura frontonasalis

Fronto-ethmoidal suture

sutura frontoethmoidalis

Coronal suture

sutura coronalis

Frontomaxillary suture

sutura frontomaxillaris

Frontolacrimal suture

sutura frontolacrimalis

Frontozygomatic suture

sutura frontozygomatica

Zygomaticomaxillary suture

sutura zygomaticomaxillaris

Lambdoid suture

sutura lambdoidea

Ethmoidomaxillary suture

sutura ethmoidomaxillaris

Ethmoidolacrimal suture

sutura ethmoidolacrimalis

Temporozygomatic suture

sutura temporozygomatica

Internasal suture

sutura internasalis

Squamous suture

sutura squamosa

Nasomaxillary suture

sutura nasomaxillaris

Lacrimomaxillary suture

sutura lacrimomaxillaris

Lacrimoconchal suture

sutura lacrimoconchalis

Intermaxillary suture

sutura intermaxillaris

Sagittal suture suture

sutura sagittalis

Palatomaxillary suture

sutura palatomaxillaris

Palato-ethmoidal suture

sutura palatoethmoidalis

Median palatine suture

sutura palatina mediana

Transverse palatine suture

sutura palatina transversa

Spheno-occipital synchondrosis

synchondrosis sphenooccipitalis

Sphenopetrosal synchondrosis

synchondrosis sphenopetrosa

Petro-occipital synchondrosis

synchondrosis petrooccipitalis