fetal skull

 fetal skull (भ्रूण की खोपड़ी ) : - 

fetal skull is to some extent compressible and made mainly of thin pliable tabular (flat) bones forming the vault. This is anchored to the rigid and incompressible bones at the base of the skull.

(भ्रूण की खोपड़ी कुछ हद तक संकुचित होती है और मुख्य रूप से पतली लचीली टेबुलर (सपाट) हड्डियों से बनी होती है जो vault (गुंबद ,arch ) बनाती है। यह खोपड़ी के आधार पर कठोर और असम्पीडित हड्डियों के लिए लंगर डाले हुए है।)

AREAS OF SKULL: The skull is arbitrarily divided into several zones of obstetrical importance These are:

 Vertex : It is a quadrangular area bounded anteriorly by the bregma and coronal sutures behind.

(वर्टेक्स: यह एक चतुष्कोणीय क्षेत्र है जो पीछे ब्रेग्मा और कोरोनल suture से घिरा होता है. लैम्ब्डा और लैम्बडॉइड suture  द्वारा और बाद में पार्श्विका श्रेष्ठता से गुजरने वाली रेखाओं द्वारा। )

 Brow : It is an area bounded on one side by the anterior fontanel and coronal sutures and on the other side by the root of the nose and supraorbital ridges of either side.

(भौंह: यह एक तरफ पूर्वकाल फॉन्टानेल और कोरोनल suture से घिरा हुआ क्षेत्र है और दूसरी तरफ नाक की जड़ और दोनों तरफ सुप्राओबिटल लकीरें हैं। )

 Face : It is an area bounded on one side by root of the nose and supraorbital ridges and on the other, by the junction of the floor of the mouth with neck.

Sinciput is the area lying in front of the anterior fontanel and corresponds to the area of brow and

the occiput is limited to the occipital bone.

Flat bones of the vault are united together by non-ossified membranes attached to the margins of the bones. These are called sutures and fontanels. Of the many sutures and fontanels, the following are of obstetric significance.

(चेहरा: यह एक तरफ नाक की जड़ और सुप्राओबिटल लकीरों से और दूसरी तरफ, मुंह के तल के जोड़ से गर्दन से घिरा हुआ क्षेत्र है। सिनसिपुट पूर्वकाल फॉन्टानेल के सामने स्थित क्षेत्र है और भौंह के क्षेत्र से मेल खाता है और पश्चकपाल पश्चकपाल हड्डी तक सीमित है। तिजोरी की चपटी हड्डियाँ के हाशिये से जुड़ी गैर-ओसिफ़ाइड झिल्लियों द्वारा आपस में जुड़ी होती हैं हड्डियों। इन्हें टांके और फॉन्टानेल कहा जाता है। कई टांके और फॉन्टानेल्स में से, निम्नलिखित प्रसूति महत्व के हैं।)

SUTURES: -

 The sagittal or longitudinal suture lies between two parietal bones.

 The coronal sutures run between parietal and frontal bones on either side.

 The frontal suture lies between two frontal bones.

 The lambdoid sutures separate the occipital bone and the two parietal bones.

Importance: (1) It permits gliding movement of one bone over the other during molding of the head, a

phenomenon of significance while the head passes through the pelvis duringlabor.

 (2) Digital palpation of sagittal suture during internal examination in labor gives an idea of the manner of engagement of the head (asynclitism or synclitism), degree of internal rotation of the head and degree of molding of the head.

FONTANELS: Wide gap in the suture line is called fontanel. Of the many fontanels (6 in number), two are of obstetric significance:

 (1) Anterior fontanel or bregma and 

  (2) Posterior fontanel or lambda.

Anterior fontanel : It is formed by joining of the four sutures in the midplane. The sutures

are anteriorly frontal, posteriorly sagittal and on either side, coronal. The shape is like a diamond.

Its anteroposterior and transverse diameters measure approximately 3 cm each. The floor is formed by a membrane and it becomes ossified 18 months after birth. It becomes pathological, if it fails to ossify even after 24 months.

Importance:

 Its palpation through internal examination denotes the degree of flexion of the head.

 It facilitates molding of the head.

 As it remains membranous long after birth, it helps in accommodating the marked brain growth; the brain

becoming almost double its size during the first year of life.

 Palpation of the floor reflects intracranial status—depressed in dehydration, elevated in raised intracranial

tension.

 Collection of blood and exchange transfusion, on rare occasion, can be performed through it via the superior longitudinal sinus.

 Cerebrospinal fluid can be drawn, although rarely, through the angle of the anterior fontanel from the lateral ventricle. Fetal skull showing important sutures, fontanels and diameters of obstetric significance.

Posterior fontanel: It is formed by junction of three suture lines — sagittal suture anteriorly and lambdoid suture on either side. It is triangular in shape and measures about 1.2 × 1.2 cm (1/2" × 1/2"). Its floor is membranous but becomes bony at term. Thus, truly its nomenclature as fontanel is misnomer. It denotes the position of the head in relation to maternal pelvis. Sagittal fontanel: It is inconsistent in its presence. When present, it is situated on the sagittal suture at the junction of anterior two-third and posterior one-third. It has got no clinical importance.

DIAMETERS OF SKULL : The engaging diameter of the fetal skull depends on the degree of flexion present. The anteroposterior diameters of the head which may engage are:-