The Human Skull
The human body is complex, consisting of various organs, muscles, ligaments, tissues and bones all with their own names and roles. When considering a career it nursing it is imperative that you have a complete understanding of the human body before attempting to move onto more complicated, complex subjects. When undertaking training and education in the medical field you must learn to walk before you can run.
The skull or cranium is at the very top of the human body. To the untrained eye the skull may appear to be one large bone but this is not the case. The skull consists of 23 different sections. These sections are the Coronal suture, Frontal bone, Sphenoid bone, Ethmoid bone, Lacrimal bone, Lacrimal canal, Nasal bone, Zygomatic bone, Condyloid process, Maxilla, Mental foramen, Mandible, body, Coronoid process, External auditory meatus, Mastoid process, Mandibular fossa, Zygomatic process, Occipital bone, Lambdoidal suture, Temporal bone, Squamosal suture and the Parietal bone.
The Coronal suture is a fibrous connective tissue joint which is rather dense which separates the parietal and frontal bones of the human skull. When born, these bones of the skull do not meet. In the event of particular bones of the skull growing too fast the sutures may close prematurely which may result in deformities of the skull such as “Oxycephaly” which is characterised by a high tower-like skull or “Plagiocephaly” which is characterised by a twisted and asymmetrical skull.
The frontal bone of the human skull bares a resemblance to a cockleshell and is made of two portions. These portions are the squama frontalis which is a vertical portion which corresponds with the forehead region and the Pars Orbitalis which is in an orbital or horizontal position and enters into the formation of the top of the nasal and orbital cavities.
The Sphenoid bone (the word sphenoid is derived from the Greek word sphenoeides which means “wedgelike”) is a singular bone in a shape resembling a butterfly which is located at the base of the human skull in front of both the temporal bone and basilar part of the occipital bone. This bone is one of seven which combine to form the orbit.
The Ethmoid bone is located at the roof of the nose between the two orbits or eye sockets and is one of the bones which make up the orbit of the eye. This bone is responsible for separating the nasal cavity from the brain and is cubical in shape and is of a spongy construction making it lightweight.
The smallest and most fragile bone in the human face is the Lacrimal bone which is located at the front section of the medial wall of the eye socket. This bone consists of two surfaces and four borders.
The Lacrimal Canals (also known as “Lacrimal canaliculi” or “Lacrimal ducts”) are the channels located in each eyelid which are small in size and originate at tiny orifices which are known as puncta lacrimalia.
The Nasal bones in the human skull are two small sized bones which are oblong in shape which vary in both size and form from person to person. These bones are beside one another in the upper and middle section of the face and form the “bridge” of the nose.
The entirety of the skull is often referred to as the body of the skull.
The cheekbone is known as the Zygomatic bone or the malar bone. This bone is a paired bone of the skull and goes with the maxilla, temporal bone, frontal bone and the sphenoid one. This bone is situated at the higher lateral area of the face and the prominence of the cheek, a section of the lateral wall and also the floor of the orbit is formed by this one.
The condyloid process is thicker than the coronoid and is a part of the mandible. This bone consists of two portions which are the condyle and the neck which is the constricted portion which is responsible for supporting it.
The maxilla is two bones which are fused along the palatal fissure which forms the upper jaw. It is similar to the lower jaw.
The Mental foramen is the name given to one of two holes which are located on the anterior surface of the mandible and allows the mental nerves and vessels passage.
The Mandible is the bone which forms the lower jaw and holds the lower teeth in place.
The coronoid Process is a thin and triangular shaped bone which is flat from side to side and varies both in size and shape. The coronoid process has 2 borders, anterior and posterior and also 2 surfaces lateral and medial.
External auditory meatus
The External auditory meatus is a tube which runs from the outer ear in to the middle ear and is known as the ear canal. This ear canal in humans spans from the pinna to the eardrum with a length of 26mm on average and a diameter of 7mm.
The mastoid process is of a cone shape and projects from the under the surface of the mastoid section of the temporal bone and is located slightly behind the ear canal and lateral to the stylod process. In males this Mastoid process is larger than in females and they do somewhat vary in size and form.
The Mandibular Fossa is in the temporal bone and is bounded by its front by the articular tubercle and behind by the tympanic section of the bone which is responsible for separating it from the external ear canal. A narrow slit divides it into two sections; this slit is known as the petrotympanic fissure.
The zygomatic process protrudes from the rest of the skull such as a bumper on a car does with the majority of it belonging to the zygomatic bone. Other bones also contribute to it as well such as the frontal bone, maxilla and the temporal bone which then from the zygomatic process of frontal bone, the zygomatic process of maxilla and the zygomatic process of temporal bone.
The saucer shaped membrane bone which is located at the lower rear section of the skull is the occipital bone and is shaped like a trapezoid and curves onto itself. A large oval aperture pierces this bone to allow the skull cavity to communicate with the vertebral canal.
The lambdoid suture is a connective tissue joint which is both dense and fibrous located on the outside area of the skull. This suture is what connects the parietal bone and the temporal bone to the occipital bone.
The temporal bones are located and both the sides and also the base of the cranium and the temporal bone support the section of the face which is known as the temple.
Arching backwards from the pterion and connecting the temporal squama with the lower order of the parietal is the squamosal suture. This suture continues behind the parietomastoid suture which unites the mastoid process and the region of the mastoid angle of the parietal with one another.
The parietal bones together form the sides and the roof of the human skull. These bones are all irregular in form with two surfaces, four borders and also four angles.