5.Development of Cartilages Bones of Facial Skeleton.pdf

Development of Cartilages & Bones of Facial Skeleton 1-Fibrous membrane 2- Flat Bones of skull 3- ostoid osreoblast osteoclast 4- Foramina...

Development of Cartilages & Bones of Facial Skeleton 1-Fibrous membrane 2- Flat Bones of skull 3- ostoid osreoblast osteoclast 4- Foramina Dr. Bnar Hamaali Mohammed 5- Cranial Base BDS, KBMS Periodontics The First & The Only Franchise in the Iraq 1 The embryology of the first pharyngeal (branchial) arch The First & The Only Franchise in the Iraq 2  The first pharyngeal arch is one of a series of arches that appear in the developing embryo and give rise to the structures of the head and neck. It is also known as the mandibular arch because it gives rise to the mandible (lower jaw), as well as other structures such as the muscles of mastication and the anterior two-thirds of the tongue. The First & The Only Franchise in the Iraq 3  The development of the first pharyngeal arch begins in the fourth week of embryonic development and involves the migration and proliferation of neural crest cells. rapid reproduction The First & The Only Franchise in the Iraq 4  These cells differentiate into various types of cells, including chondrocytes, osteoblasts, myoblasts, and endothelial cells, which contribute to the formation of the bones, muscles, and blood vessels of the face and neck. myoblast relates to muscle cell endothelial cells are single layered cells that line the blood vessels The First & The Only Franchise in the Iraq 5  The mesodermal core of the first pharyngeal arch gives rise to the Meckel's cartilage, which eventually becomes the mandible. Meckel's cartilage is a temporary cartilaginous structure that serves as a template for the formation of the lower jaw. Meckel's cartilage is initially composed of a central core of mesenchymal cells surrounded by a layer of perichondrium, which produces cartilage matrix. Over time, the cartilage is replaced by bone as ossification centers form in the mandible. The First & The Only Franchise in the Iraq 6  The muscles of mastication, including the temporalis, masseter, and lateral and medial pterygoid muscles, are also derived from the first arch.. The First & The Only Franchise in the Iraq 7  The maxillary artery, which supplies blood to the face and maxilla, arises from the first arch. The First & The Only Franchise in the Iraq 8  The ectodermal layer covering the first pharyngeal arch gives rise to the ectomesenchyme, which is a precursor to the tooth-forming tissues of the oral cavity. The anterior two-thirds of the tongue is also derived from the first arch, with its sensory innervation provided by the trigeminal nerve (CN V). The trigeminal nerve is derived from the first pharyngeal arch. The trigeminal nerve is the fifth cranial nerve (CN V) and the largest of the cranial nerves. Its primary function is to provide sensory innervation to the face and is divided into three main branches. The different branches are the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves. The First & The Only Franchise in the Iraq 9 The embryology of the second pharyngeal (branchial) arch The First & The Only Franchise in the Iraq 10  The second pharyngeal arch, also known as the hyoid arch, is one of a series of arches that appear in the early development of the embryo. It is formed during the fourth week of embryonic development and gives rise to a number of structures in the head and neck. The First & The Only Franchise in the Iraq 11 The First & The Only Franchise in the Iraq 12  Reichert's cartilage develops from the mesenchyme of the second pharyngeal arch, which is a structure that appears in the early stages of embryonic development. The First & The Only Franchise in the Iraq 13  dorsal=back ventral=front As the cartilage forms, it takes on a distinctive "S" shape, with the dorsal portion of the cartilage forming the stapes bone, and the ventral portion forming the styloid process of the temporal bone. The remainder of the cartilage forms the lesser horn and upper body of the hyoid bone. styloid process The First & The Only Franchise in the Iraq 14  The second pharyngeal arch also gives rise to the sensory innervation of the head and neck, including the chorda tympani nerve (which carries taste information from the anterior two-thirds of the tongue), the lingual nerve (which carries general sensation from the anterior two-thirds of the tongue), and the glossopharyngeal nerve (which carries sensation from the posterior one- third of the tongue and the oropharynx). The First & The Only Franchise in the Iraq 15 The bone Formation Process The First & The Only Franchise in the Iraq 16  Endochondral bone formation Endochondral bone formation is one of the two processes by which bone is formed during embryonic development and in the growth of bones during postnatal life. This process involves the replacement of a cartilaginous template, with bone tissue. The First & The Only Franchise in the Iraq 17 The First & The Only Franchise in the Iraq 18  During endochondral bone formation, a cartilage model is first formed. This cartilage model is gradually replaced by bone tissue through a series of steps. Blood vessels invade the cartilage, and cells called osteoblasts begin to form bone tissue at the site of invasion. As the bone tissue grows, it gradually replaces the cartilage until the entire model is converted to bone. The First & The Only Franchise in the Iraq 19 The First & The Only Franchise in the Iraq 20  Endochondral bone formation is responsible for the formation of most of the bones in the body, including the long bones of the arms and legs, the bones of the pelvis, and the vertebrae of the spine. This process is also involved in bone growth during childhood and adolescence, as well as bone repair after injury. The First & The Only Franchise in the Iraq 21  Intramembranous Bone Formation. It involves the direct ossification of mesenchymal cells within a fibrous membrane. This process is responsible for the formation of the flat bones of the skull, as well as the clavicles and some facial bones. The First & The Only Franchise in the Iraq 22 The First & The Only Franchise in the Iraq 23  During intramembranous bone formation, mesenchymal cells within the fibrous membrane differentiate into osteoblasts, which then produce bone matrix. The bone matrix becomes mineralized, and eventually, the mesenchymal cells are completely surrounded by bone. The mesenchymal cells differentiate into osteocytes, which are fully mature bone cells. The First & The Only Franchise in the Iraq 24 The First & The Only Franchise in the Iraq 25 The First & The Only Franchise in the Iraq 26 The First & The Only Franchise in the Iraq 27  Skull components The First & The Only Franchise in the Iraq 28  Cranial kasay sar vault The cranial vault, also known as the calvaria, is the part of the skull that encloses and protects the brain. It is formed by the frontal bone, parietal bones, the squamous parts of the temporal bone and occipital bone. The cranial vault is dome- shaped and forms the upper and back parts of the skull. The First & The Only Franchise in the Iraq 29 The First & The Only Franchise in the Iraq 30  The bones of the cranial vault are joined together by immovable fibrous joints called sutures. The sutures allow for some flexibility and movement during birth and growth, but as an adult, the bones fuse together to provide maximum protection for the brain. The First & The Only Franchise in the Iraq 31  The cranial vault also contains several foramina (openings) that allow for the passage of nerves and blood vessels These include the foramen magnum, which is the large opening in the base of the skull through which the spinal cord passes, and the paired temporal, parietal, and occipital foramina, which allow for the passage of nerves and blood vessels to and from the brain. The First & The Only Franchise in the Iraq 32  Cranial base The cranial base is the part of the skull that supports the brain and provides attachment for the structures of the head and neck. It forms the floor of the cranial cavity and separates the brain from the structures of the face and neck. The First & The Only Franchise in the Iraq 33  The cranial base is composed of several bones, including the ethmoid, sphenoid, occipital, and temporal bones. These bones are joined together by fibrous connective tissue called sutures, which allow for slight movement during birth and growth. The First & The Only Franchise in the Iraq 34  Facial bones The human face is composed of 14 bones that make up the facial skeleton. The First & The Only Franchise in the Iraq 35 The First & The Only Franchise in the Iraq 36 The First & The Only Franchise in the Iraq 37 Early skull development The First & The Only Franchise in the Iraq 38  Membranous neurocranium During fetal development, the skull is initially composed of soft tissues that gradually harden into bone. The membranous neurocranium is involved in this process, and plays a critical role in the development of the cranial bones. The First & The Only Franchise in the Iraq 39  The bones that develop from the membranous neurocranium include the frontal bone, the parietal bones, the occipital bone, and the temporal bones. These bones form the protective shell around the brain and provide attachment sites for the muscles of the head and neck. The First & The Only Franchise in the Iraq 40  -Viscerocranium cartilages The viscerocranium, also known as the facial skeleton, is the part of the skull that consists of bones and cartilages that form the face and the base of the skull. The First & The Only Franchise in the Iraq 41 The First & The Only Franchise in the Iraq 42 The First & The Only Franchise in the Iraq 43