FETAL SKULL PPT .pptx

Content is helpful to the students those who are doing masters in Obstetrics and Gynecological nursing.

1. SUBMITTED TO: PRESENTED BY: Mrs. Anugrah Milton Komal Upreti Head Of Department M.Sc. Nursing Obstetrics & Gynaecological Nursing First Year RAK College Of Nursing DISSCUSSION ON FETAL SKULL

2. INTRODUCTION Understanding the anatomy of the fetal skull and its diameter will help you recognise how a labour is progressing, and whether the baby's head is 'presenting' correctly as it comes down the birth canal. This will give you a better understanding of whether a normal vaginal delivery is likely, or if the mother needs referral because the descent of the baby's head is not & making sufficient progress. The fetal head is large in relation to the fetal body compared with the adult. The fetal skull is the most difficult part of the baby to pass through the mother's pelvic canal, due to the hard bony nature of the skull. Adaptation between the fetal skull and the pelvis is necessary to allow the head to pass through the pelvis during labour without complications.

3. OBJECTIVES Define the fetal skull. Enumerate the importance of fetal skull. Describe the divisions and regions of the fetal skull. Enlist the bones which constitute the fetal head. Elaborate the sutures and fontanelles in fetal skull and their importance. Describe the various diameters and circumferences of the fetal skull and their significance. Discuss the moulding and its relevance. Identify types of injury that can occur to the fetal skull during labour and birth.

4. DEFINITION OF FETAL SKULL Fetal skull is the part of fetal body which encase and protect the brain. Skull is compressible to some extent because it made up of thin flat bones which forms the vault. This is anchored to the rigid and incompressible bones at the base of the skull.

5. IMPORTANCE OF FETAL SKULL Largest part of the fetal body. Most frequent presenting part of the fetus during delivery. Least compressible among all the fetal parts.

6. DIVISONS OF FETAL SKULL The fetal skull has divided into 3 major parts: VAULT: The vault is the large, dome-shaped part above an imaginary line drawn between the orbital ridges and the nape of the neck. BASE: The base comprises bones that are firmly united to protect the vital centres in the medulla oblongata. FACE: The face is composed of 14 small bones that are also firmly united and non-compressible.

7. REGIONS OF FETAL SKULL VERTEX It is a quadrangular area bounded anteriorly by the bregma and coronal sutures behind the lambda and lambdoid sutures and laterally by lines passing through the parietal eminences. BROW It is an area bounded on one side by the anterior fontanelle and coronal sutures and on the other side by the root of the nose and the supra orbital ridges of the either side. The base comprises bones that are firmly united to protect the vital centres in the medulla oblongata.

8. FACE It is the area bounded on one side by root of the nose and supra orbital ridges and on the other, by the junction of the floor of the mouth and neck. The point between the eyebrows is known as glabella. SINCIPUT It is the area lying in front of the anterior fontanelle and corresponds to the area of brow. OCCIPUT It is the area limited to the occipital lobe. REGIONS OF FETAL SKULL

9. BONES OF FETAL HEAD Fetal head is consists of 7 bones: 2 Frontal bone 2 Parietal bone 2 Temporal bone 1 Occipital bone

10. SUTURES AND ITS TYPES

11. IMPORTANCE OF SUTURES It permits gliding movement of one bone over the other during moulding of the head , a phenomenon of significance while the head passes through the pelvis during labour. Digital palpation of sagittal suture during internal examination in labour gives an idea of the manner of engagement of the head, degree of internal rotation of the head and degree of moulding of the head.

12. FONTANELLES AND ITS TYPES

13. Sub-mento bregmatic (SMB) Measured from the point where the chin joins the neck to the centre of the bregma. 9.5cm in diameter. Sub- occipito bregmatic (SOB) Extends from the nape of the neck to the centre of the bregma. 9.5cm in diameter. Occipitofrontal (OF) Measured from the occipital eminence to the glabella. 11.5cm in diameter. Sub-mento vertical (SMV) Measured from the point where the chin joins the neck to the highest point on the vertex. 11.5cm in diameter. D I A M E T E R S O F S K U L L Sub-occipitofrontal (SOF) Extends from the nape of the neck to the anterior end of the anterior fontanelle or the centre of the sinciput. 10cm in diameter. Mento vertical (MV) Measured from the point of the chin to the highest point on the sagittal suture. 14cm in diameter.

14. D I A M E T E R S O F S K U L L Biparietal diameter Extends between two parietal eminences. Whatever may be the position of the head, the diameter nearly always engages. 9.5cm in diameter. Bitemporal diameter It is the distance between the antero-inferior ends of the coronal suture. 8.2cm in diameter. Super- subparietal diameter It extends from a point placed below one parietal eminence to a point placed above the other parietal eminence of the opposite side. 8.5cm in diameter.   Bimastoid diameter It is the distance between the tips of mastoid process. 7.5cm in diameter.

15. CIRCUMFERENCES Circumference of the plane of the diameter of engagement differs according to the attitude of the head.   ATTITUDE OF THE HEAD PLANE OF ENGAGEMENT SHAPE CIRCUMFERENCE Complete Flexion Biparietal sub occpito bregmatic Almost round 27.5cm Deflexed   Biparietal sub occpito frontal Oval 34cm Incomplete extension Biparietal mento vertical Bigger oval 37.5cm Complete extension Biparietal sub mento bregmatic Almost round 27.5cm .

16. The overlapping of the fetal skull bones at the suture line. (Wylie, 2005, p.201) It is the alteration of the shape of the fore-coming head while passing through the resistant birth passage during labour. (D C Dutta,2013,p.86) Bones of vault allow slight bending and override one another at the sutures. Skull changes shape from ovoid to cylindrical. Causes presenting diameter to decrease while increasing the diameter at right angles. MOULDING

17. MECHANISM OF MOULDING: There is compression of the engaging diameter of the head with corresponding elongation of the diameter at right angle to it. Thus, in well flexed head of the anterior vertex presentation, the engaging suboccipito bregmatic diameter is compressed with elongation of the head in mento-vertical diameter which is at right angle to suboccipito bregmatic. IMPORTANCE OF MOULDING: Slight moulding is good and beneficial because it enables the head to pass more easily, through the birth canal. Shape of the moulding can be a useful information about the position of the head occupied in the pelvis.

18. GRADING There are three gradings:- Grade-1 —the bones touching but not overlapping. Grade-2 — overlapping but easily separated. Grade-3 —fixed overlapping.

19. INJURIES DURING THE DELIVERY OF HEAD CAPUT SUCCEDANEUM Oedematous swelling that occurs on the presenting part. Present at birth. Can cross over the sutures. Soft swelling and will indent with pressure. Decreases following delivery. No treatment is required. Will disappear approximately 24-48hrs after birth. Moulding will also be apparent.

20. INJURIES DURING THE DELIVERY OF HEAD CEPHALOHEMATOMA Bleeding that occurs between the bones of the fetal skull and periosteum. Occurs 12-72 hours after birth. The swelling is restricted to one area and will not indent with pressure. Does not cross over the sutures. Can be bilateral. Persist for a few weeks and occasionally months.

21. BIBLIOGRAPHY Burden, B. and Sapsed , M.S., The Fetal Skull. In: Macdonald, S.,Magill -Cuerden (eds.) Mayes' Midwifery 14th ed. London: Ballière Tindall, 2011, page no: 96-104. Wylie, L., Essential anatomy and physiology in maternity care. 2nd ed. Edinburgh: Elsevier,2005,page no: 201-206. Shirish S Sheth , Essential of Obstetrics, 1st Edition, Jaypee Brothers Medical Publishers, New Delhi,2004, page no.: 102 - 104. Diane M, Myles Textbook for Midwives, 14th edition, Elsevier Publisher, London, 2008, page no: 118-123. Dutta D C, Textbook of obstetrics,7 th edition, New central book agency (P) ltd. ,London ,2013, page no: 83-87. Shirish N Daftary , Manual of obstetrics,2 nd edition, Elsevier publication, 2007, Page no: 68-72.