Human Skull Bones: Anatomy and Functions
Classified in Biology
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Cranial Bones
Frontal Bone
The Frontal Bone is an unpaired, flat bone located on the top and front of the head. It forms the "roof" of the orbits and the root of the nose.
Sphenoid Bone
The Sphenoid Bone is an unpaired bone located in the anterior base of the skull. It has a body and six extensions: two greater wings, two lesser wings, and two pterygoid processes. Through these, it is inserted like a wedge between the other bones of the skull.
Occipital Bone
The Occipital Bone is an unpaired bone located posteroinferiorly in the skull. Its lowest part, which forms part of the skull base, features the foramen magnum. This opening connects the cranial cavity, housing the brain, to the spinal canal, which contains the spinal cord, thus allowing the continuity of the central nervous system. Its two condyles articulate with the atlas (first cervical vertebra).
Ethmoid Bone
The Ethmoid Bone is an unpaired bone located centrally, anterior to the sphenoid and inferior to the frontal bone. It is involved in forming the skeleton of the nasal passages and features two pairs of turbinates (superior and middle) that increase the olfactory area.
Parietal Bones
The Parietal Bones are paired bones located in the lateral region of the skull, contributing to the formation of the cranial vault. Both bones articulate through a serrated sagittal suture.
Temporal Bones
The Temporal Bones are paired bones located on the bottom and side of the skull. Each consists of three parts: the squamous part, the petrous part, and the mastoid process. On its inner side is the petrous part, which forms part of the skull base and contains the organs of hearing.
Facial Bones
Nasal Bones
The Nasal Bones are paired, laminar bones located on either side of the midline. They form part of the nasal bridge and have anterior and posterior surfaces.
Lacrimal Bones
The Lacrimal Bones are paired, laminar bones located in the inner region of the orbital cavity. They feature a groove for the lacrimal sac.
Inferior Nasal Conchae
The Inferior Nasal Conchae are paired bones, but unlike the superior and middle turbinates (which are part of the ethmoid bone), these are independent. They belong to the nasal cavity and have a convoluted shape that significantly increases their surface area.
Zygomatic Bones (Malar Bones)
The Zygomatic Bones are paired, quadrilateral bones located in the outermost part of the face. They articulate with the maxilla and the temporal bone, forming the zygomatic arch.
Vomer Bone
The Vomer Bone is an unpaired bone that forms a significant part of the nasal septum, separating the two nostrils.
Maxilla
The Maxilla consists of paired bones that form the upper jaw. They contain alveoli along their inferior border where the upper teeth are housed. Within the bone's thickness is a large excavation called the maxillary sinus, which is connected to the nasal cavity. On its inner side, it has a palatine process that forms the hard palate.
Mandible (Lower Jaw)
The Mandible is an unpaired bone located in the lower face, forming the lower jaw itself. It has a horseshoe shape and is divided into two main parts: a body, whose upper border contains alveoli for the lower teeth, and two rami (lateral parts), which articulate with the temporal bone via condyles. A symphysis is present in the middle of the body.
Other Bones
Hyoid Bone
The Hyoid Bone is a small, unpaired bone situated in the anterior neck. It is U-shaped and consists of a body and four extensions: two greater horns (cornua) and two lesser horns (cornua). It provides attachment for various muscles and parts of the tongue. As a floating bone, it does not articulate directly with any other bone of the skeleton.