To most people, a “brain bleed” simply means any bleed inside your head. However, a doctor – and specifically doctors who treats brain bleeds (neurologists and neurosurgeons) – would say that a “brain bleed” (also known by the medical term intracranial hemorrhage) is too broad of a term. These doctors further describe brain bleeds by their exact location.
To better understand brain bleeds, it’s important to have a basic understanding of the different types. First, there are two main areas where bleeding can occur – bleeding can occur either within the skull but outside of the brain tissue, or inside the brain tissue. These areas are further divided as follows:
Bleeding within the skull but outside of the brain tissue
The brain has three membranes layers (called meninges) that lay between the bony skull and the actual brain tissue. The purpose of the meninges is to cover and protect the brain. Bleeding can occur anywhere between these three membranes. The three membranes are called the dura mater, arachnoid, and pia mater.
Epidural bleed (hemorrhage): This bleed happens between the skull bone and the utermost membrane layer, the dura mater.
Subdural bleed (hemorrhage): This bleed happens between the dura mater and the arachnoid membrane.
Subarachnoid bleed (hemorrhage): This bleed happens between the arachnoid membrane and the pia mater.
A view of the inner head showing the area -- the meninges -- between the skull and brain tissue. Brain bleeds can occur in the meninges layers, which are dura mater, arachnoid and subarachnoid space.
Brain bleeds can occur within the meninges, which is the area inside the skull but outside the actual brain tissue.
Bleeding inside the brain tissue
Two types of brain bleeds can occur inside the brain tissue itself – intracerebral hemorrhage (also called cerebral hemorrhage and hemorrhagic stroke) and intraventicular hemorrhage.
Intracerebral hemorrhage: This bleeding occurs in the lobes, pons and cerebellum of the brain (bleeding anywhere within the brain tissue itself including the brainstem).
Intraventricular hemorrhage: This bleeding occurs in the brain’s ventricles, which are specific areas of the brain (cavities) where cerebrospinal fluid is produced.
Epidural bleed, subdural bleed and subarachnoid bleed are brain bleeds outside of the actual brain tissue. Intraventricular hemorrhage and intracerebral hemorrhage are bleeds that occur inside the brain tissue.
Brain bleeds can occur in the meninges layers outside the brain tissue or inside the brain tissue itself.