Prenatal Diagnosis: Significance, Indications and Methods

Overview:

Streele and Breg in 1966 established that the chromosomal make up of a fetus could be determined by study of cultured cells from the amniotic fluid. Due to the well-known association between the advanced maternal age and an increased risk of Down syndrome, the role of prenatal diagnosis as a medical service was of utmost importance.

Definition

Prenatal diagnosis in simple term indicates the ability to detect abnormalities in an unborn child.

Gross Anatomy and Blood Supply of Spinal Cord

Spinal cord is the part of the nervous system houses inside the vertebral column. It serves as a very important conduit for the passage of various ascending and descending nervous pathways to and from the higher centers.


Chromosome and Chromosomal Disorders


What is a chromosome?

The genes are arranged in precise arrays to form a linear unit known as chromosome
It consists of DNA and proteins called Chromatin.
Heterochromatin refers to highly coiled regions where genes aren’t expressed.
Euchromatin refers to loosely coiled regions where genes can be expressed.

Chromosomes contain the genetic information necessary to direct the development and functioning of all cells and systems in the body. They pass on hereditary traits from parents to child (like eye color) and determine whether the child will be male or female.

Cerebellum: Gross anatomy and main connections


This note describes the gross features of cerebellum and its main connections.

Developmental source: It develops from the metencephalon division of rhombelcephalon (hind brain).



Basal Nuclei: Types, main features and connections



This note briefly describes the gross features of basal nuclei and their main connections.



Basal nuclei represent a collection of masses of gray matter situated within each cerebral hemisphere.



They are

o   the caudate nucleus



o   the lentiform nucleus
consists of globus pallidus medially and putamen laterally



o   the amygdaloid nucleus, and



o   the claustrum


Thalamus: location, relations, parts, nuclei and main connections

The Diencephalon: General Overview

Diencephalon is part of the prosencephalon (forebrain).
It corresponds largely to the structures that develop lateral to the third ventricles.

The lateral walls of the diencephalon form the epithalamus most superiorly,
the thalamus (dorsal thalamus) centrally and
the subthalamus (Ventral Thalamus) and 
the hypothalamus  most inferiorly.

The epithalamus:
anterior and posterior paraventricular nuclei,
the medial and lateral habenular nuclei,
the stria medullaris thalami and
the pineal gland

Cerebrum: Gross features and Blood Supply

Gross Anatomy of the Cerebral Hemispheres

The cerebral hemispheres make up the largest portion of the brain and are separated by a deep midline sagittal fissure called the longitudinal cerebral fissure.

The surface of each cerebral hemisphere is thrown into folds or gyri (sing: gyrus) which are separated from each other by sulci (sing: sulcus) or deeper fissures.
For descriptive purpose, the cerebral hemisphere is divided into lobes which are named according to the overlying cranial bones.


Main Sulci & Fissures

The surfaces of the cerebral hemispheres contain many fissures and sulci.
  1. Central sulcus
  2. Lateral sulcus
  3. Parieto-occipital sulcus
  4. Calcarine sulcus
These four sulci separates the cerebral lobes from each other.