Clinical anatomy of scalp

Clinical anatomy of scalp

1.      Which layers of scalp is known as dangerous layer of scalp?

·       4^th layer, the subaponeurotic layer of scalp is known as dangerous layer of scalp.

·        Why ?

·       Due to loose spaces blood and pus tent to collect in this space and this space contain emissary veins which connect veins of scalp to the venous sinuses of cranium. So infection from this layer spread into the venous sinuses of cranium.

2.     Functional importance of sub aponeurotic layer of scalp

·       In case children injury of vault, blood from intra cranial hematoma accumulate in 4^th layer of scalp, so no sign of intracranial pressure rise was seen

3.      Why bleeding under surface of periosteum of skull bone cause cephalohaematoma

It is a hemorrhage of blood between the skull and the periosteum of particular skull bones. It  is a typically harmless condition that causes blood to pool under a newborn's scalp after a difficult vaginal delivery. Periosteum of skull bone, the innermost layer of scalp is loosely attach to bone except near the suture, so hemorrhage below this layer make shape of individual bone. It is more see in parietal region.

4.     Why a blow on head lead to “black eye’ ?

·       Injury of the scalp causes collection of blood into the 4^th layer of scalp, the sub-aponeurotic layer of scalp. Frontalis muscle which cover part of forehead of scalp has no bony attachment and due to gravity blood accumulated in the scalp go downward and accumulate under the eye.

5.     After scalp injury, why blood accumulate under the eye but not goes laterally and posteriorly.?

·       The epicranial aponeurosis of scalp and occipitalis muscles have bony attachments to superficial temporal lines and superior nuchal lines, so blood cannot go laterally and posteriorly  but frontalis muscle has no bony attachment so blood always track downward and settle under the eye.

6.     Why wounds of scalp bleed profusely? 

·       It has two causes

·       The scalp is rich in blood supply

·        For epicranial aponeurosis (or galea aponeurotica) which is a tough layer form by dense fibrous tissue and  scalp blood vessel adhere with it which prevent vasocontriction , so scalp injury bleed more.  

7.     Why transverse scalp injury tend to create  more gap?

Ans Epicranial aponeurosis (or galea aponeurotica), the 2^nd layers of the scalp which is  a tough layer made by  dense fibrous tissue which runs from the frontalis muscle anteriorly to the occipitalis posteriorly. So there is a  tension present within the epicranial aponeurosis from anterior posteriorly. So a large gap is created when injury occur in transversely but injury occur in anterior posterior direction is not followed by large gap.    

8.     Caput succedaneum is swelling of the scalp in a newborn. It is most often brought on by pressure from the uterus or vaginal wall during a head-first (vertex) delivery. 

9.     Clinical anatomy of Caput succedaneum

It  is swelling due to collection of fluid in the  4^th layer(loose areolar tissue)  of scalp in a newborn. It is most often brought on by pressure from the uterus or vaginal wall during a head-first (vertex) delivery. It is subsides with 1-2 days