How do skull joints protect the brain


What is the skull

The skull (cranium) forms the bony basis of the head and the top of the body. It is made up of various individual bones and fulfills several tasks. Hence, its anatomy is also quite complicated. The skull is roughly divided into a brain skull and a facial skull.

Brain skull (neurocranium)

The brain skull includes:

  • the frontal bone
  • the sphenoid bone (sphenoid bone)
  • the paired temporal bone (os temporale) with the ossicles
  • the paired parietal bone (os parietale)
  • the occiput (os occipitale)

The skull seams form the articulated connection between the individual skull bones. In young children they are even more flexible than in adults - the skull bones in newborns must be able to move so that the child's head can fit through the birth canal.

At birth, the child's skull also has several small, membranous openings between the adjacent skull bones, the so-called fontanelles. The largest is on top of the newborn's head between the parietal bones and the frontal bones. In the course of the first few months of life, the fontanelles close - they ossify.


The upper part of the skull is called the roof of the skull or skullcap. It is formed by the frontal, parietal and occipital bones.

Skull base

The lower part of the skull is called the base of the skull. You can read more about this part of the skull in the post Skull Base.

Sphenoid bone

The sphenoid bone is involved in building the base of the skull - a bone shaped like a bat with its wings open. You can read more about this in the article Sphenoid Bone.

Frontal bone

The arched bone edge above the eyes, where the eyebrows sit on the skull, belongs to the frontal bone (os frontale).

The connective tissue bone seam between the frontal bone and the two parietal bones is called the crown seam. It runs roughly where a headband is worn.

Temporal bone

The temporal bone belongs to the temporal bone and houses the inner ear. Read more about this in the article Temporal bone.

The occiput, which forms the lower area of ​​the back of the head, is connected to the first cervical vertebra (atlas) via a joint.

Facial skull (viscerocranium)

The facial skull includes:

  • the ethmoid bone (ethmoid bone)
  • the paired nasal bone (os nasale)
  • the paired tear bone (os lacrimale)
  • the paired lower turbinate (Concha nasalis inferior)
  • the ploughshare (vomer)
  • the paired zygomatic bone (Os zygomaticum)
  • the paired palatine bone (os palatinum)
  • the upper jaw (maxilla)
  • the lower jaw (mandible)

The ethmoid bone is the most fragile bone in the skull. It represents the border to the cerebral cavity. Its middle part forms the upper part of the nasal septum, its lateral parts are chambered. These chambers, called ethmoid cells, belong to the paranasal sinuses and border the eye socket with a wafer-thin wall. The upper ethmoid bone cells are closed by the frontal bone, the lower ones by the upper jaw and the lacrimal bone. The number, size and extent of ethmoid cells vary greatly from person to person.

The connection between the sphenoid bone and the ethmoid bone in the area of ​​the skull base represents the transition from the cerebral to the facial skull.

Eye socket

The eyeball lies protectively embedded in the eye socket. You can find out more about this in the article Eye socket.

Nasal bone

A punch in the face quickly breaks the nasal bone. You can read more about these paired facial bones in the article nasal bone.

Tear bone

The two delicate tear bones that lie on the sides behind the nasal bones are the smallest facial bones. They are reminiscent of a fingernail in shape and size. Each tear bone forms a so-called tear pit together with one of the two upper jaw bones. The tear fluid is collected in the tear sac housed here and drains through the nasal cavity when we cry.

Zygomatic bone

The cheekbone is also called the cheekbones or cheekbones. You can find out more about these paired facial bones in the article cheekbones.

Lower jaw

The lower jaw is the largest and strongest facial bone and - apart from the auditory ossicles - the only freely movable bone in the skull. You can read more about this in the article Lower jaw.

upper jaw

The upper jaw carries the upper row of teeth and forms most of the hard palate. You can read more about the maxilla in the article Upper jaw.

Temporomandibular joint

The upper and lower jaw are not directly connected to one another via a joint. Rather, the lower jaw hangs on the two temporal bones. The extremely articulated link between them are the temporomandibular joints. You can read more about them in the article TMJ.