Growth and Development of Craniofacial skeleton

1. 1 Growth and development Growth and development of craniofacial skeleton of craniofacial skeleton Prepared by Prepared by Dr. Mohammed Alruby Dr. Mohammed Alruby G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Definitions Growth center and sites Facial processes Types of bone and bone cells Growth of cranial vault Growth of cranial base Growth of maxilla Growth of mandible Age changes Methods of studying bone growth Growth indicators G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

3. 3 Todd: growth: increase in size Development: progress toward maturity Krogman: increase in size : change in proportion and progressive complexity Meridth: segmental anatomic and physiologic changes taking place from beginning of prenatal life to senility Moyers: quantitative aspect of biologic development per unit of time Moss: change in any morphologic parameter which is measurable. By bone remodeling there is several changes in: size, shape, proportion, relationship with adjacent structure. Maxillary sinus: Like other paranasal sinuses are rudimentary at birth, they grew slowly until the age of 6 -7 years, then they enter the spurt specially the maxillary sinus. At 8 years it has a pyramidal form that will length after eruption of canine and last molar Function of sinuses: 1-Lightening of skull weight 2-Resonance of voice 3-Conditioning of air 4-Craniofacial protection Fate of pharyngeal arches: Mesodermal core of each pharyngeal arch and neural crest cells which migrate into the arches differentiate into: 1-Skeletal elements 2-Vascular elements 3-Nervous elements 4- Muscular elements Growth center Growth indicator Pushes a part Tissue separating force As: nasal cartilage Spheno occipital synchondrosis Synchondrosis 1-Cranial base 2-Interstitial growth 3-Bone replaced on both sites so it considered as double action of epiphyseal plate Center of ossification of maxilla start around the anterior superior dental arch of inferior orbital nerve and spread: Growth site Growth adjustor Pulled a part No tissue separating force As: condyle and suture Epiphyseal plate Long bones Appositional At one site G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

4. 4 Anterior: --- premaxilla Posterior ----zygomatic process of maxilla Superior ---- frontal process of maxilla Inferior: ------periosteum of alveolar process of maxilla Medial: ------- hard palate N: B: Types of bone remodeling: 1-Biomechanical remodeling: continuous deposition and removal of ions to maintain the mineral content 2-Growth remodeling: constant replacement of bone during childhood 3-Haversian remodeling: cortical reconstruction as primary vascular bone is replaced 4-Regeneration and reconstruction of bone following pathology or trauma Endochondral bone formation: = on the cartilage surface, there is -------chondroblast arranged in parallel columns while the matrix is being deposited among the columns of cells = chondroblast ----- hypertrophic and there is a lacuna become wide and so there is small strand of matrix between each cell = this matrix starts of mineralization after appear of nuclei then chondroblast ----------- chondrocyte ---------- degenerative and disappear after loss of nutrition fluids. = after time there is vascular invasion so; perichondrium changed into periosteum and the osteoblast start its action for osteoid formation = by this process there is a formation of central core of mineralized cartilage surrounded by matrix of bone -------- spongiosa---------- resorption of mineralized cartilage -------- degenerate space for vascular invasion ----------- by time is filled by red bone marrow Mandible: Have two different ways of mandibular formation: 1-Primary intramembranous calcification center arise lateral to each half of Meckel’ cartilage around the nerve and blood supply: to start ossification spread ventrally and laterally to forms body and ramus of mandible. Meckel’ cartilage after time disappear except: incus, mellus, mental ossicles that incorporated to mental region 2-Accessory cartilage: a-Condyle center: starts as separate part to form condyle and posterior part of ramus above inferior nerve b-Coronoid center: form coronoid and anterior part of ramus above the inferior alveolar nerve c-Mental ossicles: Types of bone: 1-Lamellar: collagen fibers run parallel to each other in lamellae as compact and spongy 2-Non lamellar: woven bone (embryonic bone) 3-Bundle bone: found adjacent to periosteum give attachment to ligament and tendon G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

5. 5 Synchondrosis: layer of cartilage connect bone to bone Syndesmosis: layer of CT connect bone to bone Synostosis: bridge of calcified tissue connect bone to bone Cartilaginous area of facial skeleton: 1-Mandibular condyle 2-Nasal septum 3-Spheno-occipital synchondrosis at base of skull Types of bone cells: 1-Osteoblast 2-Osteoclast 3-Osteocyte 4-Bone lining cells: will have major impact on Ca metabolism within the body Cranial vault Anatomy: 2 frontal bone------- metopic suture 2 parital bone --------sagittal suture 1 occipital bone Coronal suture = lambdoid suture Origin: intramembranous Width: coronal suture and lambdoid suture Cranial fontanelles; anterior: bregma: 2---3 years of life Posterior: lambda: 1 years of life 2 anterior lateral: sphenoid petrion -------- close soon after birth 2 posterior lateral: mastoid sterion ---------close soon after birth Cranial base Origin: intramembranous and endochondral bone formation Anatomy: anterior cranial base: nasion to sella Posterior cranial base: sella to basion Sutures: 1-Front- ethmoidal suture 2-Spheno-ethmoidal synchondrosis --------- 6 -7 years of age 3-Sphno-occipital synchondrosis ------------ 20 years of age 4-Inter-sphenoid ------- close before birth 5-Inter-occipital ------- 3 -5 years of age Anterior-posterior direction: = nasion to foramen cecaum: ----- thickness of frontal bone = foramen cecaum to sella turcica; ------- include the length of cripriform plate of ethmoid which is neural growth (eruption of U6 and L6) = sella turcica to basion ------ skeletal growth (eruption of U8 and L8) = cranial base complete more than half of its growth by age of 8 years G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

6. 6 Vertical direction: At occipital bone, frontal bone, greater wing of sphenoid bone Lateral direction: width: 7 to 8 years increase transverse size follow the neural pattern Maxilla Origin: intra-membranous bone formation Formed of 1-Bone: Palatal bone Maxillary bone Vomer Malar bone Zygomatic bone Pterygoid plate of ethmoid 2-Sutures: Fronto-maxillary suture Zygomatico-maxillary suture Zygomatico frontal suture Zygomatico temporal suture Fronto-nasal suture Pterygo- palatine suture Height: Half of growth by displacement due to anterior cranial base and nasal cartilage due to respiratory demands The other half, by drift, reposition on the nasal floor and deposition of the palate and alveolar process. So the nasal floor become in low level than orbital floor due to more reposition on nasal floor (V principle) and eruption of teeth increase the alveolar height Width: Sutures, appositional, direction of eruption of teeth Length: 1-Displacement to cranial base 2-Pnumatization of maxillary sinus 3-Deposition of bone at tuberosity area 4-Give chamber of eruption of 6,7 together with primary displacement N: B: Vomer: One of unpaired facial bone of skull located at mid sagittal line Articulate with sphenoid, ethmoid, right and left palatine bone, right and left maxillary bone Vomer articulate with six bones: Two with cranium: sphenoid and ethmoid Four with face: two maxillary bone and two palatine bone. And also articulate with septal cartilage of nose G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

7. 7 Mandible Origin: endochondral and intramembranous bone formation Endochondral sites: condyle, coronoid, mental ossicles, symphyseal cartilage Sites of mandibular growth: 1-Symphysis: depend on symphyseal suture until 11 years and after that fusion complete 2-Condyle: appositional growth of cartilage at the perichondrium of condyle, it is the major site of growth 3-Processes: a- alveolar process b-Muscular process: 1-Gonial process: --- masseter muscle and medial pterygoid 2-Coronoid process: temporalis muscle 3-Mental process: mentalis muscle Height: Surface apposition on the lower border of mandible Development of alveolar arch with eruption of teeth Width: Symphyseal cartilage growth V principle Remodeling from inner and outer surface of mandible Length: Secondary displacement Surface apposition Relocation at ramus area Mental foramen: early in life it is under mesial cusp of the 1st deciduous molars, in adult is below and between 1st and 2nd premolars due to backward and outward inclination of canal Role of Meckel’s cartilage: 1-It guides the development of mandible forming morphogenic template which exert tension on the ossification center 2- It participates in the development of symphysis menti 3-It serves as a means of attachment of the muscles of mastication and tongue muscles 4-It is involved in the development of middle ear ossicles 5-Contribute in the formation of articular disc of TMJ 6-It is important in shaping the palate Section of Meckel’s cartilage regard to their position: 1-Proximal or tympanic portion give raise to the mellus and incus (Richary et al 1965) 2-Anterior process of mellus formed from osgonial 3-Portion from mellus of middle ear and lingualla of mandible is transformed into spheno- mandibular ligament 4-Spin of sphenoid bone 5-Mental ossicles G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

8. 8 Age change in the mandible: At birth: = bone, mere shell containing sockets of two incisors, canine and two deciduous molars = mandibular canal: large size and run near the lower border of the bone = mental foramen opens beneath the socket of 1st deciduous molar = condyle portion in the line with the body = coronoid process: large size and project above the level of condyle Childhood: = two segment of bone become joined at symphysis from below to upward in 1st year, but trace of separation may be present at 2nd year = body become elongated in whole length, but more especially behind the mental foramen to provide space for the three molar developed = depth increase to allow for roots (increase vertical growth) = increase thickening of bone at sub-dental portion which enable the jaws to withstand the action of muscle = mandibular canal is just above the mylohyoid line = mental foramen occupies the position that usually in adult = mandibular angle become less obtuse 140 degrees Adulthood: = mental foramen opens midway between the upper and lower border of bone = mandibular canal: parallel to mylohyoid line = mandibular angle: 110 – 120 degrees Old age: = bone reduce in size with loss of teeth = mandibular canal with mental opening from it and close to the alveolar border = ramus: oblique in direction = mandibular canal: 140 = neck of condyle: less bent backward Methods of studying craniofacial bone growth 1-Vital staining: In 1736 Belchier reported that bones of animals who had eaten the madder plant were stained red color In 1739 Duhamel fed madder plant to animal, withheld it for a period prior to sacrifice as a result, the bone contained a band of red stain followed by unstained band Alizarin red was the essential dye for madder plant There are another dyes as: procion compound, trypan blue, acid alizarin blue, antibiotic tetracycline Value of such vital dyes: 1-Describe the pattern of postnatal bone deposition over an expected period in one animal 2-The manner in which the bone is laid out 3-The sites of growth 4-The direction of growth 5-The relation duration at different sites G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

9. 9 2-Radio Isotopes: Used as un-vivo marker Such labelled material is injected and then after time located within the growing bone by means of: -Giger counter -Auto-radiographic technique 3-Implant: Bjork method: implanting the bits of titanium into growing bone of animals or human being, this will serve as reference marker during several cephalometric analysis Implant growth studies: Bjork 1969: Involve implanting of small bits of biological inert alloy into growing bone:-- titanium—1.5mm length and 0.5 diameter In maxilla: -Hard palate behind the deciduous canine (prior eruption of maxillary permanent incisors) -Below anterior nasal spin after eruption of maxillary incisors -Two implant on either side of zygomatic process of maxilla -Border between hard palate and alveolar process medial to 1st molar In mandible: -Anterior aspect of symphysis in midline below root tips -Two pins on right side of mandibular body, one under 1st premolar and one below 2nd premolar or 1st molar -One pin on the external aspect of the right ramus at the level of occlusal surface of molars 4-Comparative anatomy: Significant contribution to the knowledge of human facial growth have been provided through comparison with other species 5-Craniometry: Measurements of skull to determine its characteristic related to sex, race, or body type 6-Genetic studies: Used to study parents’ child relationship There are different genetic factors in the dentofacial development The problem is to identify the specify, site, timing, and mechanism of any such genetic control 7-Natural markers: The persistence of certain developmental features of bone has led to their use as natural markers using certain radiograph -Trabecula -Nutrient canal -Incremental lines (lines arrested growth) This can use for reference to study deposition, resorption, and remodeling 8-Removal of parts to study growth: As cartilaginous nasal septum and its effect on the forward growth G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

10. 10 9-Histologic study: Study matrix and its density Beam of x-ray and microscopic level is passed through un-calcified thin section of bone placed over sensitive emulsion Different passage of ray, record on the film as varying ---- black, gray, while colors 10-Split line technique: Benninghoff 1925 Bone is partially decalcified making it soft enough and punched with needle India ink inserted in these split to make them visible and fixes permanently (pattern of trabecula) Growth indicators History: 1896: Sydney Rowand record hand & wrist x-ray after 6 months from discover x-ray in London 1900: Pryor Rotch 1928: Helman and Haward 1936: Flory (Sesamoid) stage of begins calcification 1-Hand & wrist radiograph: = Using left hand or use 1st ,2nd, 3rd finger on the front of cephalometric film in attempt to reduce the dose of radiation = Most common published by Greulish and Pyle in 1959 = TW2 (Tuner and white house 2) make developmental score with twenty bones on hand and wrist = the long axis of third finger in direct line with axis of forearm = the thumb is placed in the most comfortable natural degree of rotation with its long axis making 30 degree with 1st finger = tube is centered above the third metacarpal at a tube film distance of 30 inches or 75cm = hand and wrist views may be interpreted by many ways: a-Either comparing the radiograph with series of standard films represent normal children at different age b-Time of occurrence of certain ossification events in relation to spurte growth c-By assessing score to developmental age of 20 bones in hand and wrist (TW2 1975) (phalanx, radius, ulna) Methods: -Greulish Pyle 1959 -TW2 1975 -Singer method 1980 -Hagg and Taranger 1980 -Fishman 2-Adductor sesamoid: Sesamoid of the adductor bravis muscle at the metacarpo-pharyngeal joint of thumb Sesamoid bone: bone embedded within tendon or muscle, it is derived from Latin ward (sesamum) (seasamy seads) due to small size. Sesamoid bone found on joint throughout the body: a-Knee: the patella b-Hand --- two sesamoid, most used that present within the tendon of adductor pollicis c-Wrist: the pisiform of the wrist within tendon of flexor carpi ulnaris G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

11. 11 d-In foot: 1st metatarsal e-In neck Described by Champan 1972 as the following: ASO: no ossification AS1: pin point ossification AS2: ossification more than pin point but not identified AS3: seed shape: well defined outline, measured about 3mm x2mm ------- short female and 3mm x 4mm -------- long male 3-Cervical vertebrae: Lampanraski 1972 Hassel and Farman 1995 Fishman 1982 Baccelli et al 2000 Franchi and Macnamara Anatomy: C1: atlas: Known as atlas vertebrae is the 1st of upper most of 33 vertebrae of spinal column of cervical vertebrae 1st, 2nd vertebrae are distinct from the other true vertebrae or removable vertebrae below them within the neck C2: axis: 2nd cervical vertebrae, 2nd upper most vertebrae Name axis derived from its role in allowing the head to rotate from its support at C1 where the skull attach the neck C3: Setting below the C2 axis, from C3 to C6 are grouped together Composed of: -Vertebral arch: protect spinal cord -Ventral body centrum: provide strength, protection and mobility to the body C4: Small in relation to the other vertebrae but with large vertebral foramen for passage of nerves of spinal Cervical vertebrae maturation: CVM: Depend on: C2, C3, C4 Definition of cervical vertebrae maturation stages: Cs1: the lower border of all 3 vertebrae C2 – C4 are flat The bodies of C3 and C4 are trapezoid in shape Cs2: a concavity is present at the lower border of C2 in 80% of cases. The bodies of both C3 and C4 are trapezoid in shape Cs3: concavities at the lower border of both C2 and C3 are present. The bodies of C3 and C4 can be either trapezoid or rectangular horizontal in shape. Cs4: concavities at lower border of C2, C3 and C4 now present, the bodies of C3 and C4 are rectangular horizontal in shape Cs5: the concavities at lower border of C2, C3, C4 still present at least body of C3 or C4 square in shape. If not square the body of others cervical vertebrae still rectangular horizontal G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby

12. 12 Cs6: the concavities at lower border of C2, C3 and C4 still present At least body of C3 or C4 is rectangular vertical in shape if not rectangular is square 4-Frontal sinus: Rossow 1991: analysis the size of frontal sinus highest point and lowest point and relate to SN line 5-Dental development: 1-Nolla calcification stages 1960 2-Bjork and Hellman 1967 3-Hagg and Taranger 1982 4-Damaergian 1982 5-Chertknow 1980: calcification stage of permanent lower canine at the close to the ossification on sesamoid of adductor 6-Lower third molar development: a-Tooth germ visible b-Cusp formation c-Crown formation complete d-Half of root formed e-Root formation complete but apex not closed 7-Other indicators: a-Body weight and hight b-Chronological age c-Growth velocity d-Concentration of growth hormone G Growth rowth and development of craniofacial skeleton and development of craniofacial skeleton Dr. Mohammed Alruby Dr. Mohammed Alruby