Craniometry.pptx

cranio

1. CRANIOMETRY

2. Craniometry : It is the technique used to measure dry skull after removal of its soft parts . A landmark on the skull from which craniometric measurements can be taken are craniometric points . A landmark may be defined as a definite anatomical point or an indefinite point located by geometrical relations which form the termini of the direct measurement.

3. Points : Unpaired: N asion, glabella, bregma, akanthion, lambda, orale, opisthocranion, basion, staphylion . Binate: P teryon, porion, euryon, zygion, gonion, endomolare .

4. Unpaired: Nasion : The intersection of the nasofrontal suture with the midsagittal plane. Nasion is the uppermost landmark for the measure of facial height. Glabella : The most forward projecting point in the midline of the forehead at the level of the supra-orbital ridges and above the nasofrontal suture. Bregma : The intersection of the coronal and sagittal sutures in the midline.

5. Lambda : The intersection of the sagittal and lambdoidal sutures in the midline. Opisthocranion : The most posterior point on the skull not on the external occipital protuberance. It is the posterior end point of maximum cranial length measured from glabella. It is determined instrumentally. Basion : The midpoint of the anterior margin of the foramen magnum.

6. Binate : Porion : The uppermost lateral point in the margin of the external auditory meatus. The right and left porion with the left orbitale define the Frankfort Horizontal. Zygion : The most lateral point of the zygomatic arch. It is determined instrumentally.

7. Gonion : The midpoint of the angel of the mandible between body and ramus. Euryon : The two points on the opposite sides of the skull that form termini of the lines of greatest breadth. The two points are determined instrumentally. Pterion: Estimated as 2 finger-breadths above the zygomatic arch and a thumb’s breadth behind the frontal process of the zygomatic bone.

8. O rale E ndomolare S taphylion B asion

9. G labella N asion A kanthion G nathion B regma L ambda O pistocranion

10. P orion P teryon

11. Z ygion E uryon G onion

12. Length: Glabella - Opisthocranion Width: Euryon - Euryon High: Bregma - Basion SIZE OF THE SKULL

13. Length: Nasion - Gnathion Width: Zygion - Zygion SIZE OF THE FACE

14. Width: Endomolara - Endomolare Length: Orale - Staphylion SIZE OF THE PALATUM

15. Skull is the upper most part of the human skeleton consisting of head and face. The human skull consists of 22 bones. Except for the mandible (lower jaw), all the bones of the skull are connected together by sutures. The skeleton of a skull without mandible is called Cranium which is made up of 8 bones and thirteen bones form the facial skeleton. The mandible is a movable bone held to the cranium by ligaments. The cranial bones can be divided into two categories: the calvaria and the cranial base. The calvaria is the domeshaped superior portion of the cranium. It is composed of the frontal, occipital, and parietal bones, and the flat portion of the temporal bones. The cranial base is composed of the two remaining cranial bones, the ethmoid and the sphenoid bone . Fourteen facial bones form the other components of the skull. The facial bones are composed of the inferior nasal conchae , lacrimal bones, mandible, maxillary bones, nasal bones, palatine bones, vomer and zygomatic bones. SKULL

16. CRANIOMETRIC MEASUREMENTS (I) Cranial circumference Max. cranial breadth Min. frontal breadth Bigonial breadth Upper facial height Basion-Prosthion length Nasal breadth (max.) Lower nasal breadth Orbital breadth Biorbital breadth Foramen magnum breadth

17. Cranial height Max. cranial length Bizygomatic breadth Total facial height Basion-Nasion length Basal height Upper nasal breadth Orbital height Interorbital breadth Palate-external breadth & length Palate-internal breadth & length

18. CRANIOMETRIC MEASUREMENTS (II) Condylo-symphyseal length Bicondylar width Min. ramus breadth Mandibular body height Symphyseal height Mastoid length Ascending ramus height Mandibular body breadth Mandibular body length Total facial angle Mid-facial angle Alveolar angle Nasion-Opisthion arc Transverse arc Sagittal cord Coronal cord

19. INSTRUMENTS USED FOR CRANIOMETRY Instruments like spreading caliper, sliding caliper, steel tape and mandibulometer are used while recording craniometric measurements . Calipers Calipers are the most important instruments available for measuring distances between two definite points. There are two types of calipers-Spreading and Sliding .

20. Spreading Caliper This instrument is available in two sizes i.e. 25 cm long for taking smaller measurements and another one 60 cm long for taking the measurements on Pelvis and hence it is called as Pelvimeter. The caliper comprises of two long arms which are curved outwards and bounded at one end. A meter scale is fixed to one of the arms and passes through the socket on the second arm. The spreading calipers are made with blunt or rounded ends and sharp or pointed ends . The spreading caliper with rounded or blunted ends is used to make measurements on living human being, whereas, the spreading caliper with sharp or pointed end is employed to record measurements on skeletons. The calipers are graduated up to one millimeter

21. Spreading Caliper

22. Sliding Caliper

23. CRANIOMETRIC MEASUREMENTS The procedures for various craniometric measurements are presented as below : Maximum Cranial Length (g - op): It measures the straight distance between glabella (g) and opisthocranion (op ). Instrument: Spreading Caliper (Pointed end ) Procedure: A skull is placed on the working table or on the seed bag. One point of spreading caliper is kept on the glabella and other point is moved to the posterior region of the skull on the occipital bone in midsagittal plane and wherever the maximum length is observed it should be measured.

24. Recording of Cranial Length

25. Maximum Cranial Breadth ( eu – eu ): It is the maximum breadth ( width) measured on the skull on right angle (90º) to the mid- sagittal plane . Instrument: Spreading Caliper Procedure: Place the skull on the working table or on the seed bag. Keep the two points of the spreading caliper on two sides of the euryon with the two hands in the same horizontal plane and record the measurement.

26. Recording of cranial breadth

27. Maximum Bizygomatic Breadth ( zy – zy ): It measures the straight distance between two zygia ( zy ) which are the most laterally placed points on the zygomatic bone . Instrument: Spreading caliper Procedure: A skull is placed on the table in norma verticalis position . Two points of the spreading caliper are kept on zygion of either side of the skull, wherever maximum breadth observed it should be recorded .

28. Basion-Bregma Height ( ba – b ): It measures the straight distance between basion ( ba ) and bregma (b ). Instrument: Spreading caliper Procedure: The skull is placed in norma lateralis position while right side rests on the pad. Basion and bregma landmarks are located on the skull. One end of spreading caliper is kept on the basion on the backside of the skull and the other end of the caliper is moved to the bregma of the skull and the measurement is made .

29. Upper Facial Height (n – pr): It measures the straight distance between nasion (n ) to prosthion (pr ). Instrument: Sliding caliper Procedure: The skull has to be placed in such a manner that the occipital region rests on the pad. One point of sharp end of caliper is kept on nasion and the movable point is extended to the prosthion and the measurement is recorded.

30. Minimum Frontal Breadth (ft): It measures the straight distance between frontotemporale located on either side of the skull . Instrument: Sliding caliper Procedure: A skull is placed on the working table. Frontotemporale on either side of the skull are identified. One sharp end of the caliper is placed on the frontotemporale on the one side of the skull and the movable point is spread up to the frontotemporal end on the other side of skull and wherever the least distance is observed the measurement should be made.

31. Morphological Facial Height (n – gn ): It measures the straight distance between nasion and gnathion . Instrument: Sliding Caliper Procedure: The measuring skull should be placed towards the measurer . Nasion and gnathion landmarks are identified on the skull. The sharp end of the caliper is kept on the nasion and the movable part of the caliper touches the gnathion and the measurement is made.

32. Nasal Height (n – ns): It measures the straight distance between nasion and nasospinale . Instrument: Sliding Caliper Procedure : The skull is kept in such a manner that the basal region rests on the pad . The fixed point of cross-bar is placed on nasion (n) and the movable crossbar is adjusted against the nasospinale (ns ).

33. Nasal Breadth: It measures the maximum breadth of the pyriform aperture. Instrument: Sliding Caliper Procedure: The skull to be kept on the working table. The measurement should be taken by Sliding Caliper by placing the two ends of the cross-bars on the two farthest points of the nasal aperture.

34. Facial length or Facial depth ( ba -pr): It measures the straight distance between basion and prosthian . Instrument: Sliding Caliper Procedure: The skull is placed in the position of norma basalis on the working table facing the measurer. Identify the prosthion and basion landmarks on the skull. One sharp point of Sliding Caliper is kept on the prosthion and the movable point is spread to the level of basion and the measurement is made.

35. Upper Facial height (n-pr): It measures the straight distance between nasion and prosthion . Instrument: Sliding Caliper Procedure: The skull is placed on the working table in frontal part facing the measurer . Nasion and Prosthion landmarks are identified. One sharp end of the sliding caliper is kept on nasion and the movable point is drawn to the prosthion .

36. Horizontal Circumference of skull (g-op-g): It is the maximum circumference of the cranium in horizontal plane over glabella (g) – opisthocranion (op )- glabella (g ). Instrument: Measuring tape Procedure: The skull is placed facing frontal region facing the measurer. The landmark opisthocranion is located which is found on the back of the skull. Passing the tape through opisthocranion the maximum circumference between glabella to glabella is measured.

37. Morphological Facial height (n- gn ): It measures the straight distance between nasion and gnathion . Instruments: Sliding Caliper Procedure: The skull is placed on the working table facing frontal region to the measurer. Identify and mark the nasion and gnathion landmarks. Keep one sharp point of the Sliding Caliper on gnathion and draw the movable sharp point towards nasion and record the measurement.

38. Breadth of the Upper Jaw or Bimaxillary Breadth ( zm-zm ): It measures the straight distance between two zygomaxillaria . Instruments: Sliding Caliper Procedure: Place the skull on the working table facing the measurer. Identify Zygomaxillare on either side of the skull. Keep one sharp fix point on left zygomaxillare and draw the movable sharp point towards the right zygomaxillrea and record the measurement.

39. INDICES An Index represents the relationship between two absolute measurements. Various indices can be calculated based on craniometric measurements. However, some of the indices are given below.

40. CEPHALOMETRY I t i s used in dentristy, especially in orthodontics, to gauge the size and special relationships of the teeth, jaws and cranium . This analysis informs treatment planning, quantifies changes during treatment, and provides data for clinical research .

41. CEPHALOMETRIC LANDMARKS

42. CEPHALOMETRIC POINT, PLANE, LINE AND ANGLES USED IN DENTISTRY S (Sella) : M idpoint of sella turcica N (Nasion) : M ost anterior point on fronto-nasal suture Or (Orbitale) : M ost inferior anterior point on margin of orbit Po (Porion) : U pper most point on bony external auditory meatus ANS (Anterior Nasal Spine) PNS (Posterior Nasal Spine)

43. Go (Gonion) : M ost posterior inferior point on angle of mandible Me (Menton) : L ower most point on the mandibular symphysis A ( A point) : P osition of deepest concavity on anterior profile of maxilla B ( B point) : P osition of deepest concavity on anterior profile of mandibular symphysis

44. Frankfort Plane: Po – Or Equivalent to the true horizontal when patient is standing upright Maxillary Plane: PNS - ANS Gives inclination of maxilla relative to other lines/planes Mandibular Plane: Go - Me Gives inclination of mandible relative to other lines/planes

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