Lecture 7 Flashcards
TYPES OF JOINTS
FUNCTIONAL CLASSES
- ) SYNARTHROTIC - NOT MOVEABLE (I.E. FIBROUS SUTURES)
- ) AMPHIARTHROTIC - SLIGHTLY MOVEABLE (I.E. VERTEBRAE)
- ) DIARTHROTIC - MOVEABLE JOINT (I.E. SYNOVIAL JOINT)
EXAMPLES OF JOINTS
SYNARTHROTIC -
FIBROUS SUTURE - BONY *INTERDIGITATIONS, BOUND BY DENSE FIBROUS TISSUE
*GOMPHOSIS - BINDS TEETH IN ALVEOLAR BONE SOCKET (CONSISTS OF ALVEOLAR BONE, PDL, ROOT)
BONY FUSION SYNOSTOSIS - FRONTAL SUTURE OF FRONTAL BONE AND EPIPHYSEAL LINES OF MATURE BONE ARE SYNOSTOSES (METOPIC)
DIARTHROTIC - LOCATED AT THE ENDS OF LONG BONES
*TMJ - LOCATED BETWEEN TEMPORAL AND MANDIBULAR BONES
TMJ
GINGLYMOARTHRODIAL JOINT - ALLOWS JAW TO HINGE OR SLIDE SIDE TO SIDE
GINGLYMUS - HINGE JOINT
ARTHRODIAL - SLIDING JOINT
OPEN JAW VS. CLOSED JAW AND TMJ POSITION
OPEN - CONDYLE FORWARD, DISKS SLIDE FORWARD
CLOSED - CONDYLE FITS IN SOCKET ALONG W/ DISKS
TYPES OF TMJ MOVEMENTS
- ) ELEVATION (JAW CLOSING)
- ) DEPRESSION (JAW OPENING)
- ) PROTRUSION (FORWARD)
- ) RETRACTION (BACKWARD)
- ) LATEROTRUSION (SIDEWAYS)
SYNOVIAL CAPSULE MOVEMENTS
UPPER - MOVES DURING PROTRUSION (LATERAL PTERYGOID ASSISTED BY MEDIAL PTERYGOID) AND RETRACTION (POSTERIOR FIBERS OF TEMPORALIS, DEEP PART OF MASSETER, GENIOHYOID AND DIGASTRIC)
LOWER- MOVES DURING ELEVATION (TEMPORALIS, MASSETER, MEDIAL PTERYGOID) AND DEPRESSION (GRAVITY, DIGASTRIC, GENIOHYOID, AND MYLOHYOID MUSCLES)
TMJ STRUCTURAL FEATURES
ARTICULAR DISK - FOUND IN STERNOCLAVICULAR JOINT AS WELL
COMPOSED OF FIBROCARTILAGENOUS TISSUE
SYNOVIAL DISK DIVIDES INTO UPPER/LOWER CAVITY BY ARTICULAR DISK
CONDYLAR SURFACE - FIBROUS CONNECTIVE TISSUE
CONDYLAR SURFACE FEATURES
FIBROUS CONNECTIVE TISSUE => 2˚ CARTILAGE –> PROLIFERATIVE ZONE (CHONDROGENIC => GROWTH OF CONDYLE) –> HYPERTROPHIC ZONE –> OSSEUS TISSUE
TMD SIGNS AND SYMPTOMS
PAIN OF THE JOINT PAIN UPON MOVEMENT TRISMUS (SPASMS) MANDIBULAR DEVIATION POPPING CLICKING CREPITIS (FRICTION BETWEEN BONE AND CARTILAGE) FACIAL PAIN, MYALGIA, PAIN ON OPENING
MAXILLARY DEVELOPMENT
FORMS FROM ANTERIOR MESENCHYME AND FUSES W/ MESENCHYME CELLS FROM 1ST BRANCHIAL ARCH (FORMS MAXILLARY PROCESS)
MESENCHYMAL CONDENSATION OCCURS IN ANTERIOR PORTION OF THE DEVELOPING HEAD AND MIGRATES DOWN TO OVERLAP W/ STOMODEUM OVER TIME
=> DOWNWARD PROJECTION CALLED THE FRONTO-NASAL PROCESS (FNP)
FNP INTERACTS W/ MAXILLARY PROCESS AT 4 WKS IN UTERO => MAXILLA
MAIN BULK FORMATION OF MAXILLA
PAIRED MAXILLARY PROCESSES - DEVELOP FROM CRANIAL PART OF 1ST BRANCHIAL ARCH
PAIRED MANDIBULAR PROCESSES - DEVELOP FROM CAUDAL PART OF 1ST BRANCHIAL ARCH (FORMS 1ST FOLLOWED BY MAX. PROCESSES)
OSSIFICATION OF THE MAXILLA
IM OSSIFICATION BEGINS AT THE OSSIFICATION CENTERS (APPEAR WHERE ANTEROSUPERIOR DENTAL NERVE BRANCHES FROM INFERIOR BRANCH OF INFRAORBITAL NERVE)
BONE SPREADS FROM CENTER…
POSTERIORLY - BELOW ORBIT TO DEVELOPING ZYGOMA
ANTERIORLY - TOWARD FUTURE INCISOR REGION
SUPERIORLY - TO FORM FRONTAL PROCESSES OF THE MAXILLA
SECONDARY OSSIFICATION CENTERS LOCATED
AT ZYGOMATIC, NASOPALATINE, AND ORBITONASAL AREAS
OSSIFICATION SPREADS TO PALATINE PROCESS TO FORM HARD PALATE
TYPES OF CARTILAGE
MAXILLA = MEMBRANOUS VISCEROCRANIUM (CONTACTS SPHENOID, ETHMOID - BOTH = CARTILAGENOUS NEUROCRANIUM
HYOID BONE = CARTILAGENOUS VISCEROCRANIUM (*REMEMBER, FORMED FROM REICHERT’S CARTILAGE)
DEVELOPMENT OF THE PALATE
POSTERIOR SURFACE OF THE MAXILLA OSSIFICATION PROCESSES FOR THE FORMATION OF THE PALATE ARE FORMING - STARTS AT POINTS ON THE POSTERIOR AND INFERIOR SIDE OF THE MAXILLA THAT FORM BONY PLATES THAT BECOME A MAJORITY OF THE PALATE
PALATOGENESIS
VERY IMPORTANT PROCESS THAT CAN BE INTERRUPTED AT MULTIPLE POINTS
STARTS AT WEEK 5 IN UTERO
ENDS AT WEEK 12 IN UTERO
DIRECTED BY FIELDS OF EPITHELIAL AND MESENCHYMAL CELLS
PALATE DEVELOPS FROM 2 PRIMORDIAL TISSUES
•PRIMARY - PREMAXILLARY PART OF THE MAXILLA (ANTERIOR PORTION)
•SECONDARY - PALATINE PROCESS (POSTERIOR PORTION)
•WEEK 7 IN UTERO- FUSION OF THESE 2 PALATAL SHELVES IS PREVENTED BY POSITIONING OF THE TONGUE UNTIL PALATINE PROXIMATION
*FUSION OF PALATE DOES NOT OCCUR SIMULTANEOUSLY ALONG WIDTH OF INTERMAXILLARY SUTURE - COMPLETES BETWEEN 1-2 YEARS AFTER BIRTH (FGF PLAYS A ROLE IN COORDINATION)
•WEEK 8 IN UTERO - BILATERALLY LOCATED CENTERS IN ANTERIOR PALATE => PRE-MAXILLA AND MAXILLA, PALATAL SHELVES BEGIN HORIZONTAL GROWTH TOWARDS MIDLINE
•WEEK 9 IN UTERO - PROXIMATION AT MIDLINE OCCURS W/ THE NASAL SEPTUM AND POSTERIOR PALATE OF 1˚ TISSUE
•WEEK 10 IN UTERO - FUSION OF SOFT TISSUE IN PALATE AND OSSIFICATION CENTERS GROW MEDIALLY
•WEEK 14 IN UTERO - PRE-MAXILLARY BONE => INCISORS AND MAXILLARY BONE SUPPORTS CUSPIDS 1ST MOLARS AND MID-PALATINE SUTURE SUPPORTS 2ND MOLARS
DELETION OF FGF SIGNALING ANATAGONIST
CAUSES A CLEFT PALATE TO FORM
FGF PATHWAY SIGNALS TO EPITHELIUM AND MESENCHYMAL DIRECTING CELLS TO PROMOTE COORDINATED OSTEOGENESIS OF THE PALATAL SHELVES (CLEFT PALATES CAN BE SYNDROMIC AND NON-SYNDROMIC)
MECHANISMS OF PALATE ELEVATION
DESCENT OF TONGUE BY GROWTH OF MECKEL’S CARTILAGE AND MANDIBLE
MYONEURAL ACTIVITY IN TONGUE
MOUTH OPENING REFLEXES
INTRINSIC MECHANISMS OF PALATE ELEVATION
HYDRATION/POLYMERIZATION OF INTRACELLULAR SUBSTANCES PRODUCING AN ELASTIC ELEVATING FORCE
DIFFERENTIAL GROWTH OF ONE SIDE OF PALATAL SHELF
BUILDUP OF MUCOPOLYSACCHARIDES
5-HT RELEASE FROM NEURAL TISSUE
GENESIS OF CLEFT PALATE
DELAY IN SHELF ELEVATION DISTURBANCE IN MECHANISMS OF SHELF ELEVATION FAILURE OF SHELVES TO CONTACT FAILURE TO DISPLACE TONGUE (PIERRE ROBIN SEQUENCE) FAILURE TO FUSE AFTER CONTACT FAILURE TO DISPLACE TONGUE RUPTURE AFTER FUSION DETECTIVE MERGING
FORMATION OF CLEFT PALATE
ALTERATION OF BLOOD FLOW
ALTERATION IN MUSCULAR MOVEMENTS
W/DRAWAL OF FACE FROM AGAINST HEART PROMINENCE => JAW OPENING AND TONGUE DROPPING
BRAIN GROWTH
OCCURS UNTIL 8 YEARS OF AGE
@ 2 MO. HEAD = 50%
@ BIRTH HEAD = 25% (FACE/HEAD = 1/8)
@ 25 YEARS HEAD = 12% FACE/HEAD = 1/3-1/2)
CRANIAL VAULT = INTRAMEMBRANOUS OSSIFICATION
ANTERIOR CRANIAL BASE = ENDOCHONDRAL OSSIFICATION (FULLY FORMED @ 10 YEARS)
POSTERIOR CRANIAL BASE = FULLY FORMED @ 20 YEARS
SKULL GROWTH
OCCURS W/IN SUTURES, W/IN CONTAINED ORGANS (TONGUE, EYEBALLS, BRAIN), SURFACE APPOSITION, REMODELING RESORPTION
MECHANISMS OF GROWTH
GROWTH =
1.) APPOSITIONAL GROWTH - WIDENING OF BONE (BONE DEPOSITION BY OSTEOBLASTS OF PERIOSTEUM AND MEDULLARY CAVITY MAINTAINED BY OSTEOCLASTS)
2.) LENGTHENING OF BONE (EPIPHYSEAL PLATES ENLARGE BY CHONDROBLASTS, MATRIX CALCIFICATION (BONE TISSUE REPLACES CARTILAGE ON DIAPHYSIS SIDE)
REMODELING =
DUE TO MECHANICAL STRESS, BONE TISSUES NEED TO BE REPLACED VIA OSTEOBLASTS AND OSTEOCLASTS - THEIR ACTIVITY IS IDEALLY MAINTAINED IN EQUILIBRIUM
UNTIL AGE 25 OSTEOBLAST CONCENTRATION IN BONE IS GREATER THAN OSTEOCLAST CONCENTRATION IN BONE THEN DECREASES THROUGHOUT THE REST OF THE LIFE CYCLE
OSTEOPROTEGERIN
OPG IS A DECOY RECEPTOR FOR RANK - REGULATES STIMULATION OF RANK SIGNALING PATHWAY BY COMPETING W/ RANKL
BONE RESORPTION
TRIGGERED BY PTH IN RESPONSE TO HYPOCALCEMIA (PTH => OSTEOCLASTOGENESIS)
- ) OSTEOCLASTS ADHERE TO BONE => SPECIALIZED ISOLATED COMPARTMENTS
- ) MEMBRANES ADJACENT TO BONE DIFFERENTIATE INTO RUFFLED MEMBRANES (CONTAINS PROTEINS THAT ACIDIFY COMPARTMENT ADJACENT TO BONE)
- ) ACID DISSOLVES MINERALS IN BONE - DIGESTIVE ENZYMES BREAKDOWN TYPE I COLLAGEN
THIS PROCESS ENDS WHEN OSTEOCLASTS DIE BY APOPTOSIS
COORDINATION REQUIRED
TO MAINTAIN PROPORTIONATE GROWTH IN PALATE AND MAXILLAE
TEMPOROSPATIAL
PALATAL FUSION OCCURS FROM ANTERIOR TO POSTERIOR
SECONDARY PALATE IS COMPOSED OF
2 PALATAL SHELVES OF MAXILLARY PROCESS
FRONTONASAL PROCESS
