The skull is a bone protective cavity for the brain. The skull is composed of three types of bone: cranial bones, facial bones, and ear ossicles. Two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium (braincase) and the viscerocranium that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans, these sensory structures are part of the facial skeleton.
The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats, birds and dogs, but not in whales, or most reptiles.
The occipital bone is a cranial dermal bone and the main bone of the occiput. It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of the skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord.
The parietal bones are two bones in the skull which, when joined at a fibrous joint known as a cranial suture, form the sides and roof of the neurocranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin paries (-ietis), wall.
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
In anatomy, the axis is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The spinal cord passes through the axis.
The cerebellar tentorium or tentorium cerebelli is an extension of the dura mater between the inferior aspect of the occipital lobes and the superior aspect of the cerebellum. The free border of the tentorium gives passage to the midbrain.
A synarthrosis is a type of joint which allows no movement under normal conditions. Sutures and gomphoses are both synarthroses. Joints which allow more movement are called amphiarthroses or diarthroses. Syndesmoses are considered to be amphiarthrotic, because they allow a small amount of movement.
The sphenoid sinus is a paired paranasal sinus occurring within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses. The pair of sphenoid sinuses are separated in the middle by a septum of sphenoid sinuses. Each sphenoid sinus communicates with the nasal cavity via the opening of sphenoidal sinus. The two sphenoid sinuses vary in size and shape, and are usually asymmetrical.
The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word petrosus, meaning "stone-like, hard". It is one of the densest bones in the body. In other mammals, it is a separate bone, the petrosal bone.
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal.
The basilar part of the occipital bone extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline.
The lateral half of the great wing of the sphenoid bone articulates, by means of a synchondrosis, with the petrous part of the temporal bone. Between these two bones on the under surface of the skull, is a furrow, the 'sulcus of auditory tubule, for the lodgement of the cartilaginous part of the auditory tube.
The atlanto-occipital joint is an articulation between the atlas bone and the occipital bone. It consists of a pair of condyloid joints. It is a synovial joint.
In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull, the joints between the bones are called sutures. Such immovable joints are also referred to as synarthroses.
The clivus or Blumenbach clivus is a part of the occipital bone at the base of the skull. It is a shallow depression behind the dorsum sellae of the sphenoid bone. It slopes gradually to the anterior part of the basilar occipital bone at its junction with the sphenoid bone. It extends to the foramen magnum. It is related to the pons and the abducens nerve.
Cartilaginous joints are connected entirely by cartilage. Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. Cartilaginous joints also forms the growth regions of immature long bones and the intervertebral discs of the spinal column.
The following outline is provided as an overview of and topical guide to human anatomy:
In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skullcap. The remainder of the skull is the facial skeleton.
The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy.
