What is the function of the germinal matrix?
In anatomy, the germinal matrix is a highly cellular and highly vascularized region in the brain out from which cells migrate during brain development. The germinal matrix is the source of both neurons and glial cells and is most active between 8 and 28 weeks gestation.
Which Fontanelle is primarily used for imaging the brainstem and posterior fossa?
Mastoid fontanelle imaging is particularly useful in detecting hemorrhage involving the brainstem, cerebellum, and subarachnoid cisterns. It greatly facilitates clot detection in the fourth ventricle and cisterna magna because the tissues surrounding these structures are normally echogenic.
How do you measure ventricular index?
—The ventricular index (VI) (defined as the distance between the falx and the lateral wall of the anterior horn in the coronal plane), anterior horn width (AHW) (defined as the diagonal width of the anterior horn measured at its widest point in the coronal plane), and thalamo-occipital distance (TOD) (defined as the …
What is USG cranium?
Ultrasound imaging of the head uses sound waves to produce pictures of the brain and cerebrospinal fluid. It is most commonly performed on infants, whose skulls have not completely formed. A transcranial Doppler ultrasound evaluates blood flow in the brain’s major arteries.
What causes germinal matrix hemorrhage?
The blood vessels of the germinal matrix are weak walled and predisposed to hemorrhage. A significant stress experienced by a premature infant after birth may cause these vessels to rupture. US is the modality of choice. Germinal matrix hemorrhages appear as echogenic regions close to the caudothalamic groove.
What is the germinal matrix hair?
The Germinal matrix is an area of reproducing cells situated around the papilla at the base of the hair bulb. It is the source of hair growth and is involved in transfering melanin to hair to give it pigmentation.
What is mastoid fontanelle?
The mastoid or posterolateral fontanelles are paired bilateral soft membranous gaps (fontanelles) at the junction of the parietomastoid, occipitomastoid, and lambdoid sutures. Each mastoid fontanelle persists until the second year of life, after which it is known as the asterion.
What is third fontanelle?
The third fontanelle is a bony defect along the sagittal suture about 2 cm anterior to the posterior fontanelle (3, 4, 5); it is not a true fontanelle being related exclusively to the parie- tal bones. This fontanelle can often be seen on X-rays as a depression in the contour on a lat- eral view (Fig.
What is ventricular index?
The ventricular index (VI), or width, is widely used as a tool for monitoring ventricular size. It is a measurement of the distance from the falx to the lateral border of the lateral ventricle in a coronal view taken at the level of the Foramen of Monro.
What is Evans ratio?
The Evans index (EI) is defined as the ratio of the maximal width of the frontal horns to the maximum inner skull diameter. First proposed by Evans in 1942, it has been used to indirectly assess the expansion of the ventricular system in encephalography (Evans, 1942).
Can a baby survive a brain bleed?
The prognosis varies depending on the severity and location of the bleed. Some infants do very well with little or no residual effects. More severe bleeds can result in mental and physical impairments such as developmental delays, learning disabilities, and cerebral palsy (CP).
What is the pathophysiology of germinal matrix hemorrhage?
The pathogenesis of germinal matrix hemorrhage is believed to be related to the vascular properties of the germinal matrix. Germinal matrix capillaries are unusual in that they are larger than normal systemic capillaries but are lined only with simple endothelium without the muscular or collagenous support normally seen in larger vessels (, 29 ).
Which imaging findings are characteristic of periventricular leukoma and germinal matrix hemorrhage?
Cranial ultra- sonography and computed tomography reveal periventricular leukoma- lacia, germinal matrix hemorrhage, and hydrocephalus. Magnetic reso- nance imaging is the most sensitive modality for evaluating the patterns
What happens to the basal ganglia when involved in neonatal hemorrhage?
When involved, the basal ganglia tend to cavitate and shrink without scarring. In addition, the perirolandic cortex is more likely to be spared in premature neonates than in term neonates (, 4,, 27 ). Germinal matrix hemorrhages and periventricular white matter injury may also be seen.
What are germinal matrix capillaries?
Germinal matrix capillaries are unusual in that they are larger than normal systemic capillaries but are lined only with simple endothelium without the muscular or collagenous support normally seen in larger vessels (, 29 ).