Radiological Anatomy Second Stage PDF

Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic .Dept 2nd Stage Radiological Anatomy First Semester Theory L-3 Dr Younis Ibraheem The mandible The mandible The mandible is the largest bone in the human skull. I...

Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic .Dept 2nd Stage Radiological Anatomy First Semester Theory L-3 Dr Younis Ibraheem The mandible The mandible The mandible is the largest bone in the human skull. It holds the lower teeth in place, it assists in mastication and forms the lower jawline. The mandible is composed of two halves united at the symphysis menti. Each half comprises a horizontal body and a vertical ramus joined at the angle of the mandible. The mandible The mandible The ramus has two superior projections, the coronoid process anteriorly and the condylar process posteriorly, separated by the mandibular (or condylar ) notch. The coronoid process gives attachment to the temporalis muscle, and the condylar process (or head of mandible) articulates with the base of the skull at the temporomandibular joint. The body of the mandible bears the alveolar border with its 16 tooth sockets The mandible External surface of the mandible The mandible The mandibular canal runs in the ramus and body of the bone, transmitting the inferior alveolar artery (branch of the maxillary artery) and nerve (branch of the mandibular division of the trigeminal nerve) The mandibular canal opens proximally as the mandibular foramen on the inner surface of on the external surface of the body below and between the the upper ramus, and its distal opening is the mental foramen two premolars. The inner surface of the mandible External surface of the mandible The muscles of the mandible The muscles of the floor of the mouth, including the medial pterygoid muscles, are attached to the inner surface of the mandible and the muscles of mastication are attached to its outer surface The muscles of the mandible The muscles of the mandible The temporomandibular joint This is a synovial joint between the condyle of the mandible and the temporal bone. The temporal articular surface consists of a fossa posteriorly, the temporomandibular fossa , and a prominence anteriorly, the articular tubercle, The head of the mandible sits in the fossa at rest and glides anteriorly on to the articular tubercle when fully open, The joint is least stable during occlusion. Axiolateral TMJ Closed mouth Axiolateral TMJ Closed mouth Tempromandibular joint TMJ TMJ Closed mouth The teeth – nomenclature and anatomy There are 20 deciduous or milk teeth; in the adult these are replaced by 32 permanent teeth. The complement of teeth in each quadrant is as follows: • in the child: two incisors, one canine, two molars; and • in the adult: two incisors, one canine, two premolars, three molars The teeth are referred to by their position in each of the four quadrants. The relevant quadrant is designated by two arms of a cross, and the tooth by its position relative to the midline The permanent teeth are referred to by number and the milk teeth by capital letter Thus the second right lower premolar in the adult is designated 5 and the second left upper molar in child ’ s milk dentition is designated E. a The Head Lecture 1 Dr. Azhy Rwandizy Bones of the Skull: The skull comprises several separate bones united at immobile joints called sutures. The connective tissue between the bones is called a sutural ligament. The mandible is an exception to this rule, for it is united to the skull by the Mobile temporomandibular joint. The bones of the skull can be divided into those of the cranium and those of the face. The vault is the upper part of the cranium, and the base of the skull is the lowest part of the cranium. The skull consists of the following bones, two of which are paired: • • • • • • Frontal bone: 1 Parietal bones:2 Occipital bone: 1 Temporal bones: 2 Sphenoid bone: I Ethmoid bone: I The facial bones consist of the following. Two of which are single: • Zygomatic bones: 2 • Maxillae:2 • Nasal bones:2 • Lacrimal bones: 2 • Vomer: I • Palatine bones:2 • Inferior conchae: 2 • Mandible: I • The bones forming the vault are mainly the paired temporal and parietal bones, and parts of the unpaired frontal, sphenoid, and occipital bones. • The bones forming the base of the cranium are mainly parts of the sphenoid, temporal, and occipital bones. • The bones forming the facial skeleton are the paired nasal bones, palatine bones, lacrimal bones, zygomatic bones, maxillae, inferior nasal conchae, and the unpaired vomer. 1 The mandible is not part of the cranium nor part of the facial skeleton. The foramen magnum occupies the central area of the floor and transmits the medulla oblongata and its surrounding meninges, the ascending spinal parts of the accessory nerves, and the two vertebral arteries. Anterior view The anterior view of the skull includes the forehead superiorly, and, inferiorly, the orbits, the nasal region, the part of the face between the orbit and the upper jaw, the upper jaw, and the lower jaw. 2 Lateral view The lateral view of the skull consists of the lateral wall of the cranium, which includes lateral portions of the vault and the facial skeleton, and half of the lower jaw. • bones forming the lateral portion of the vault include the frontal, parietal, occipital, sphenoid, and temporal bones; • bones forming the visible part of the facial skeleton include the nasal, maxilla, and zygomatic bones. • the mandible forms the visible part of the lower jaw. 3 Posterior view The occipital, parietal, and temporal bones are seen in the posterior view of the skull. 4 Superior view The frontal bone, parietal bone, and occipital bone are seen in a superior view of the skull. These bones make up the superior part of the vault. In an anterior-to-posterior direction: • the unpaired frontal bone articulates with the paired parietal bones at the coronal suture; • the two parietal bones articulate with each other in the midline at the sagittal suture; • the parietal bones articulate with the unpaired occipital bone at the lambdoid suture. 5 Inferior view The base of the skull is seen in the inferior view and extends anteriorly from the middle incisor teeth posteriorly to the superior nuchal lines and laterally to the mastoid processes and zygomatic arches. For descriptive purposes the base of the skull is often divided into: • an anterior part, which includes the teeth and the hard palate; • a middle part, which extends from behind the hard palate to the anterior margin of the foramen magnum; and • a posterior part, which extends from the anterior edge of the foramen magnum to the superior nuchal lines. 6 Anatomy Lecture 9 Dr.Azhy Rwandizy NASAL CAVITIES The two nasal cavities are the uppermost parts of the respiratory tract and contain the olfactory receptors. They are elongated wedge-shaped spaces with a large inferior base and a narrow superior apex and are held open by a skeletal framework consisting mainly of bone and cartilage. The smaller anterior regions of the cavities are enclosed by the external nose, whereas the larger posterior regions are more central within the skull. The anterior apertures of the nasal cavities are the nares, which open onto the inferior surface of the nose. The posterior apertures are the choanae, which open into the nasopharynx. The nasal cavities are separated: • from each other by a midline nasal septum; • from the oral cavity below by the hard palate; and • from the cranial cavity above by parts of the frontal, ethmoid, and sphenoid bones. 1 Lateral to the nasal cavities are the orbits. Each nasal cavity has a floor, roof, medial wall, and lateral wall. Lateral wall The lateral wall is characterized by three curved shelves of bone (conchae), which are one above the other and project medially and inferiorly across the nasal cavity. These conchae increase the surface area of contact between tissues of the lateral wall and the respired air. The openings of the paranasal sinuses, which are extensions of the nasal cavity that erode into the surrounding bones during childhood and early adulthood, are on the lateral wall and roof of the nasal cavities. In addition, the lateral wall also contains the opening of the nasolacrimal duct, which drains tears from the eye into the nasal cavity. Regions: Each nasal cavity consists of three general regions-the nasal vestibule, the respiratory region, and the olfactory region: • the nasal vestibule is a small dilated space just internal to the naris that is lined by skin and contains hair follicles; • the respiratory region is the largest part of the nasal cavity, has a rich neurovascular supply, and is lined by respiratory epithelium composed mainly of ciliated and mucous cells; • the olfactory region is small, is at the apex of each nasal cavity, is lined by olfactoryepithelium, and contains the olfactory receptors. 2 In addition to housing receptors for the sense of smell (olfaction), the nasal cavities adjust the temperature and humidity of respired air by the action of a rich blood supply, and trap and remove particulate matter from the airway by filtering the air through hair in the vestibule and by capturing foreign material in abundant mucus. The mucus normally is moved posteriorly by cilia on epithelial cells in the nasal cavities and is swallowed. Innervation and blood supply Innervation of the nasal cavities is by three cranial nerves: • olfaction is carried by the olfactory nerve [I]; • general sensation is carried by the trigeminal nerve [V], the anterior region by the ophthalmic nerve [V1], and the posterior region by the maxillary nerve [V2]; • all glands are innervated by parasympathetic fibers in the facial nerve [VII] (greater petrosal nerve), which join branches of the maxillary nerve [V2] in the pterygopalatine fossa. Blood supply to the nasal cavities is by: • terminal branches of the maxillary and facial arteries, which originate from the external carotid artery; and • from ethmoidal branches of the ophthalmic artery, which originates from the internal carotid artery. 3 Skeletal framework Bones that contribute to the skeletal framework of the nasal cavities include: • the unpaired ethmoid, sphenoid, frontal bone, and vomer; • the paired nasal, maxillary, palatine and lacrimal bones, and inferior conchae. External nose The external nose extends the nasal cavities onto the front of the face and positions the nares so that they point downward. It is pyramidal in shape with its apex anterior in position. The upper angle of the nose between the openings of the orbits is continuous with the forehead. Like posterior regions, the anterior parts of the nasal cavities found within the nose are held open by a skeletal framework, which is composed partly of bone and mainly of cartilage: • the bony parts are where the nose is continuous with the skull-here the nasal bones and parts of the maxillae and frontal bones provide support; • anteriorly, and on each side, support is provided by lateral processes of the septal cartilage, major alar and three or four minor alar cartilages, and a single septal cartilage in the midline that forms the anterior part of the nasal septum. Paranasal sinuses There are four paranasal air sinuses-the ethmoidal cells, and the sphenoidal, maxillary, and frontal sinuses. Each is named according to the bone in which it is found. The paranasal sinuses develop as outgrowths from the nasal cavities and erode into the surrounding bones. All are: • lined by respiratory mucosa, which is ciliated and mucus secreting; • open into the nasal cavities; and • innervated by branches of the trigeminal nerve [V]. 4 5