Skull 1 Lecture Notes PDF

 SKULL 1 Dr. Ruba Ahmad Alslehat Dr. Syeda Uzma Zahra  Reference ◦Snell’s clinical anatomy by regions. 10th edition  Introduction ◦ The skeleton of the head and neck region includes: 1. Skull(22) 2. Middle ear ossicle...

 SKULL 1 Dr. Ruba Ahmad Alslehat Dr. Syeda Uzma Zahra  Reference ◦Snell’s clinical anatomy by regions. 10th edition  Introduction ◦ The skeleton of the head and neck region includes: 1. Skull(22) 2. Middle ear ossicles(6) 3. Hyoid bone(1) 4. Cervical vertebrae(7)  Skull ◦ The skull is composed of several separate bones united at immobile fibrous joints called sutures. ◦ The connective tissue between the bones is called a sutural ligament. ◦ Only the mandible is united to the skull by the mobile synovial temporomandibular joint. ◦ The bones of the skull can be divided into: 1. Cranial bones: surrounds the brain(8) 2. facial bones(14) Neurocranium(cranial bones) vs viscerocranium(facial bones) ◦ Cranial bones: two ◦ Facial bones: two of of which are which are single: paired ◦ Zygomatic bones: 2 ◦ Frontal bone: 1 ◦ Maxillae: 2 ◦ Parietal bones: 2 ◦ Nasal bones: 2 ◦ Occipital bone: 1 ◦ Temporal bones: 2 ◦ Lacrimal bones: 2 ◦ Sphenoid bone: 1 ◦ Vomer: 1 ◦ Ethmoid bone: 1 ◦ Palatine bones: 2 ◦ Inferior conchae: 2 ◦ Mandible: 1 ◦ The cranial cavity is the space containing the brain(interior of the skull). ◦ The skull vault(calvarium) is the upper part of the cranium and forms the roof and side walls of the cranial cavity. ◦ The base of the skull is the lowest part of the cranium and forms the floor of the cranial cavity.  the skull is studied in six views, each is called norma: From below: From inside : From in front : From behind : From above : From the side : Norma basalis Norma basalis Norma frontalis Norma occipitalis Norma verticalis Norma lateralis. externa interna  Norma frontalis Made of three parts: 1. Upper part: Forehead; made of the frontal bone 2. Middle part: contains 3 O O caviteis;2 orbital & 1 N nasal 3. Lower part: formed by the upper & lower jaws Norma frontalis  Norma frontalis 1. Frontal bone 2. Zygomatic bone 3. Maxilla 4. Mandible 5. Nasal bone 6. Orbital aperture 7. Anterior nasal aperture Frontal bone  Frontal bone 1. The superciliary arches: Superomedial to each orbit is a rounded superciliary arch between which there may be a median elevation, the glabella. 2. Glabella: median elevation between the superciliary arches 3. Nasion: point depression at which the internasal and frontonasal sutures meet 4. Frontal eminence: the most prominent areas on either side of the forehead 5. The supraorbital foramen: which transmits supraorbital nerve and vessels.  Frontal bone Glabella Nasion Supraorbital foramen/fissure Nasal bones  Maxilla It has a body and 4 processes The body contains maxillary paranasal sinus Maxillae form parts of 3 cavities:  Orbital cavity  Nasal cavity 1  Oral cavity 4 1. Frontal process of maxillary 2 bone Infraorbital foramen 2. Zygomatic process of maxillary 3 bone 3. Alveolar process of maxillary Anterior nasal spine bone: The two alveolar processes unite to form the alveolar arch (= upper jaw) 4. Orbital plate: forms the floor of orbit  processes of maxilla (4) 1.Frontal process of 2. Zygomatic process of 3. Alveolar process of 4. Palatine process of maxillary bone maxillary bone maxillary bone maxillary bone  Incisive foramen ◦ Palatine process of maxillary bone: Extends medially to form the majority of: The Hard Palate. ◦ Articulates with: the palatine process of the opposite side and the horizontal plate of the palatine bone  Maxilla Orbital plate of maxillary sinus maxillary bone Anterior nasal spine of maxillary bone  Zygomatic bone (cheek bone) 1. Frontal process of Zygomatic bone 2.Maxillary process of Zygomatic bone 3. Orbital plate of zygomatic bone: forms the floor and lateral wall of 1 the orbit 3  zygomatico -facial foramen 2 zygomatico-facial foramen 1  zygomatico-temporal foramen 4. Temporal process of zygomatic bone Temporal process of zygomatic bone articulates with zygomatic process of temporal bone to form the zygomatic arch  Mandible (lower jaw) Mental foramen Maxillary process of frontal bone Frontal process of maxillary bone Zygomatic process of maxillary bone Maxillary process of zygomatic bone Zygomatic process of frontal bone Frontal process of zygomatic bone Supraorbital foramen/fissure Notice that the Infraorbital foramen supraorbital, infraorbital and mental foramina lie in the same vertical line. Mental foramen  Norma verticals Bones: ◦ Anteriorly : The frontal bone ◦ Laterally : The two parietal bones ◦ Posteriorly : The occipital bone Sutures: ◦ The coronal suture : between the frontal bone and the two parietal bones. ◦ The sagittal suture : between the two parietal bones. ◦ The lambdoid suture : between the occipital bone and the two parietal bones.  Norma verticals ◦ Meeting points : The bregma : Coronal suture Frontal bone ◦ Is the meeting of the coronal and sagittal sutures. ◦ It is the site of the anterior fontanelle Bregma The lambda : ◦ Is the meeting of the lambdoid and sagittal sutures. Parietal bone Sagittal suture ◦ It is the site of the posterior fontanelle. Vertex: highest point of the skull Lambdoid suture Occipital bone Lambda  Anterior fontanelle Posterior fontanelle Shape Rhomboidal Triangular Time of closure closes 1.5-2 years after closes 3-6 months after birth. (18months) birth After closure It is the site of the It is the site of the bregma lambda  Norma occipitalis ◦ Posterior view of the skull ◦ Superior: the posterior parts of the two parietal bones with the sagittal suture. ◦ Inferior: squamous part of occipital bone and lambdoid suture  Norma occipitalis Parietal bone Parietal bone  External occipital protuberance : is a Occipital bone median elevation on the occipital bone.(attachment to muscles and the ligamentum nuchae) Lambdoid  External occipital crest : extends from the suture protuberance to the foramen magnum.  The superior nuchal lines : extend laterally from the external occipital protuberance  Highest nuchal line superior nuchal line Inferior nuchal line External occipital protuberance External occipital crest  External occipital crest ‫ﺷﻜﺮا ً‬