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In anatomy, the meninges (/ m ə ˈ n ɪ n dʒ iː z /; [1] [2] sg. meninx / ˈ m iː n ɪ ŋ k s, ˈ m ɛ n ɪ ŋ k s /; [3] from Ancient Greek μῆνιγξ (mêninx) 'membrane') [4] are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater.
The dura mater covering the spinal cord is known as the dural sac or thecal sac, and only has one layer (the meningeal layer) unlike cranial dura mater. The potential space between these two layers is known as the epidural space , [ 5 ] which can accumulate blood in the case of traumatic laceration to the meningeal arteries .
The spinal cord is protected by three layers of tissue, called spinal meninges, that surround the canal. The dura mater is the outermost layer, and it forms a tough protective coating. Between the dura mater and the surrounding bone of the vertebrae is a space called the epidural space .
The spinal epidural space spans the length of the spinal cord, from the foramen magnum superiorly to the sacral hiatus inferiorly. [6] Epidural space is the smallest at the cervical region, measuring 1 to 2 mm. At L2 to L3, enlarges until 5 to 6 mm. It then enlarges progressively until lower lumbar and sacral region. [7]
The cranial cavity has a variety of spinal and cranial nerves residing in it. The cranial nerves are responsible for storing sensory information needed for taste, smell, sight and the ability to hear. The spinal nerves allow for the sensory and motor signals to be received, which provide a normal feeling and function for the arms and legs.
The arachnoid mater is interposed between the two other meninges, the more superficial (closer to the surface) and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The delicate arachnoid layer is not attached to the inside of the dura but against it, and surrounds the brain and spinal cord.
The meningeal branch of the mandibular nerve (also known as the nervus spinosus) [1] is a sensory branch of the mandibular nerve (CN V3) that enters the middle cranial fossa through either the foramen spinosum or foramen ovale to innervate the meninges of this fossa as well as the mastoid air cells. [2]
The CNS is protected by the cranium, vertebral column, meninges, cerebrospinal fluid. The spinal cord is an extension of the brain. The spinal cord and the brain stem are joined at the base of the cranium at the foramen magnum. Most of the functions of the head and neck are directly influenced by the brain and transmitted to the PNS via the ...