Answer
The brain is the most important organ of the body, consequently, it is well protected.
In order to get access to brain tissue, a surgeon would have to cut through the following overlying
structures.
1. Skin
a . epidermis
b. dermis
c. hypodermis
2. Muscles of the scalp or aponeurosis
3. Cranial bone
4. Meninges
Cerebrospinal fluid (CSF) and brain capillaries (BBB) would also have to be moved from the
area of surgery.
Work Step by Step
The structures that are external to the brain include the the integumentary tissue ,
aponeuroses and muscles ( over some bones). Apart from the hair, these tissues offer only minimal protection to underlying brain tissue. Hair, epidermis, dermis, hypodermis, aponeuroses, and muscles would have to be removed before getting to the real protection of cranial bones.
Layers of tissues above brain tissue.
1. The skin--epidermis, dermis
2. Connective tissue
3. Periosteum( pericranium)
Just exterior to the outer compact layer of the flat bones is a periosteal layer of connective
tissue. Over some bones there is an aponeurosis (Galea Aponeurotica); over others there are
cranial muscles. Examples of cranial muscles are the epicranius muscle, and the temporalis
muscle. An example of an aponeurosis is the Galea Aponeurosis
4. Cranial bones . The cranial bones form the vault and base of the skull.
These bones are the paired parietals, the paired temporals, the frontal, the occipital. the
sphenoid , and the ethmoid. The calvaria which protects the front, back, top and sides of
the brain comprises the frontal, parietal, and the occipital bones. These are flat bones that
offer maximal protection to the brain with minimal weight,
A cranial flat bone has an outer, and an inner compact layer; it also and a middle layer
cancellous matrix. This kind of bone protects in three ways:
a. The hard compact bone is difficult to break because of collagenous fibers and
mineralized matrix.
b. The cancellous bone absorb shocks. This protects against concussive injuries. The
spongy bone also lightens the weight of the calvaria.
into glancing blows, and lessens the impact of blows to the head..
5. Dura mater. This issue consists of a periosteal layer that attaches the dura to the
cranial bone, and a meningeal layer above the subdural space.
6 Arachnoid mater lies below the subdural space
7. Pia mater. Below the subarachnoid space is the pia mater, the thinnest, innermost meninx .
After cutting through all these layers, the surgeon would finally get to brain tissue.