RNAL and Child Health Nursing: Fetal Skull and Ossification

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Questions and Answers

What is the primary function of sutures in the fetal skull?

To form the structure of the skull

To allow gliding movement of bones during labor (correct)

To connect the skull to the spine

To give strength to the skull

Which of the following structures is NOT considered a major suture on the fetal skull?

Frontal suture

Temporal suture (correct)

Coronal suture

Sagittal suture

Where is the vertex of the skull positioned?

At the back of the skull

At the junction of the oral cavity and neck

Between specific sutures and parietal eminences (correct)

On the frontal bone

What shape is the anterior fontanelle characterized by?

Diamond-like Signup and view all the answers

Which bones are separated by the lambdoidal sutures?

Parietal and occipital bones Signup and view all the answers

What is the significance of the anterior fontanelle during labor?

It indicates fetal position and engagement of the head Signup and view all the answers

How many fontanelles are considered to be of obstetric significance?

Two Signup and view all the answers

What is the area called that lies in front of the anterior fontanelle?

Sinciput Signup and view all the answers

What is the primary importance of the fetal skull during childbirth?

It contains the delicate brain and is the common presenting part. Signup and view all the answers

Which bone is located at the back of the fetal skull and plays a key role in protecting the spinal cord?

Occipital bone Signup and view all the answers

How are the bones of the vault of the fetal skull primarily formed?

Laid down in membrane and ossified from the center outwards Signup and view all the answers

What do the sutures and fontanelles of the fetal skull represent?

Gaps left from unfinished ossification Signup and view all the answers

Which statement is true regarding the ossification of the fetal face?

It is almost completely ossified at birth and fused. Signup and view all the answers

What constitutes the vault of the fetal skull?

The dome-shaped area above an imaginary line between the orbital ridges and nape of the neck. Signup and view all the answers

How many main bones are generally recognized in the vault of the fetal skull?

Five Signup and view all the answers

What is indicated by the term 'parietal eminence' in relation to the fetal skull?

The ossification center of each parietal bone. Signup and view all the answers

What is the significance of the fontanelle in relation to brain growth during the first year of life?

It allows for the accommodation of brain growth. Signup and view all the answers

How does the palpation of the fontanelle floor assist in clinical evaluations?

It indicates the level of hydration in a patient. Signup and view all the answers

What diameter is associated with complete flexion of the fetal neck and presents the vertex?

Suboccipitobregmatic Signup and view all the answers

Which diameter involves incomplete extension and presents with the face?

Submentovertical Signup and view all the answers

What is the relationship between the fetal attitude and the engaging diameter of the skull?

Engaging diameter varies with degree of flexion or extension. Signup and view all the answers

Which of the following is true about the posterior fontanelle?

It is formed by the union of three suture lines. Signup and view all the answers

What measurement is associated with marked deflexion of the fetus and the vertex presentation?

Occipitofrontal diameter Signup and view all the answers

Which measurement is considered a transverse diameter critical for labor mechanics?

Biparietal diameter Signup and view all the answers

Study Notes

Course Information

Course title: RNAL AND CHILD HEALTH NURSING
Course code: NSG 403
Session: 2020/2021
Credit: 6 units
Lecturer: R.A. Oyekale
Department: Nursing, Faculty of Clinical Sciences

Fetal Skull

The fetal skull is the most important part of the fetus.
It is the most common presenting part.
It contains the delicate brain.
The head passes through the birth canal under pressure.
The skull is the largest and least compressible part of the body.
Smooth delivery is ensured after birth.
Recognition of normal presentation and positions facilitates birth.
Minimal trauma to mother and baby is achieved through proper understanding.

Ossification

Bones in the fetal head originate in two ways:
- Face: developed cartilaginous, fully ossified at birth, bones fused together
- Vault: developed membranous, flatter and more pliable, ossifies outwards from centre.
Ossification process is incomplete when born, leaving gaps
Gaps become sutures and fontanelles
Each bone has a boss/protuberance at the ossification center.

Bones of the Vault

Five main bones:
- Occipital bone: located at the back of the head, forms the base of the skull containing the foramen magnum: protects the spinal cord as it leaves the skull.
  - Has an occipital protuberance at its center
- Two parietal bones: lie on either sides.
- Ossification center of each parietal bone is called the parietal eminence.

Diagram of Bones, Sutures and Fontanelles

Diagram shows frontal bones, parietal bones, occipital bone, sutures (coronal, sagittal, lambdoid), anterior fontanel, and posterior fontanel, with measurements.

Regions and Landmarks

Skull divided into vault, base, and face.
Vault: large dome-shape part above an imaginary line between the orbital ridges and nape of the neck.
Base: comprised of bones firmly united to protect vital centers.
Face: composed of 14 bones, firmly united, non-compressible.
Regions described as:
- Vertex: quadrangular area bounded by bregma and coronal sutures, lambda and lambdoidal sutures, parietal eminences.
- Brow: area bounded by the anterior fontanelle and coronal sutures, root of nose, supra-orbital ridges.
- Face: bounded by the root of the nose and supraorbital ridges, junction of mouth floor and neck.
- Sinciput: area in front of the anterior fontanelle, similar to brow region
- Occiput: limited to the occipital bone

Sutures

Flat bones joined by non-ossified membranes (sutures).
Four major sutures:
- Sagittal/longitudinal suture: lies between two parietal bones
- Coronal sutures: between parietal and frontal bones on either side.
- Frontal suture: between two frontal bones
- Lambdoidal sutures: divide occipital and two parietal bones.

Importance of Sutures

Allows gliding movement during head moulding
Important during childbirth
Digital palpation of sagittal sutures helps assess head engagement, synclitism/asynclitism, internal rotation, and moulding degree.

Fontanelles

Gaps in suture lines called fontanelles
Two clinically significant fontanelles:
- Anterior fontanelle (bregma)
- Posterior fontanelle (lambda)
Anterior fontanelle: diamond-shaped, formed by joining four sutures,
Anteriorly: frontal suture, Posteriorly : sagittal suture, Coronal sutures on either sides
Becomes ossified 18 months after birth, pathological when delayed, its palpation, helps determine the degree of head flexion and helps in moulding.
Posterior fontanelle: triangular shape, formed by 3 sutures

Diameters of the Skull

Engaging diameter depends on flexion/extension.
Attitude: degree of fetal neck flexion/extension during delivery.
Presentation: part of the fetus located at pelvic brim/lower pole of the uterus.
Specific diameters (anteroposterior and transverse):
- Suboccipitobregmatic, suboccipitofrontal, occipitofrontal, mentovertical, submentovertical, submentobregmatic

Moulding

Skull bones allow slight bending. Bones can override at sutures.
This allows for reduction in presenting diameters.

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Description

This quiz covers essential concepts regarding the fetal skull in relation to childbirth, as well as the process of ossification in the fetal head. Understand the importance of normal presentation and positions for a smooth delivery, and learn how the skull's structure facilitates childbirth. Tighten your knowledge about the anatomy of the fetal skull and its developmental processes in nursing practice.