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    Related Topics

    From Nervous System

    Cerebrospinal Fluid (CSF)
    Protective fluid in brain and spinal cord.
    Temporal Lobe
    Involved in auditory perception and memory.
    Pituitary Gland
    Endocrine gland controlling other hormone glands.
    Parietal Lobe
    Processes sensory information such as touch, temperature, and pain.
    Lateral Ventricles
    Paired brain cavities producing CSF.
    Substantia Nigra
    Involved in movement and reward.
    Foramina of Luschka
    Lateral apertures of fourth ventricle.
    Cerebellar Peduncles
    Connect the cerebellum to the brainstem.
    Diaphragma Sellae
    Covers the pituitary gland.
    Frontal Lobe
    Controls reasoning, planning, movement, emotions, and problem-solving.
    Thoracic Spinal Cord
    Middle portion of the spinal cord.
    Medulla Oblongata
    Controls autonomic functions like breathing and heart rate.
    Thalamus
    Relay station for sensory and motor signals to the cerebral cortex.
    Vermis
    Midline structure of the cerebellum.
    Amygdala
    Involved in emotion and memory.
    Choroid Plexus
    Produces cerebrospinal fluid.
    Cingulate Gyrus
    Processes emotions and behavior regulation.
    Conus Medullaris
    Terminal end of the spinal cord.
    Internal Capsule
    White matter structure that carries information to and from the cerebral cortex.
    Insular Cortex
    Involved in consciousness, emotion, and homeostasis.
    Arbor Vitae
    White matter of the cerebellum.
    Cauda Equina
    Bundle of spinal nerves below the conus medullaris.
    Fourth Ventricle
    Cavity between brainstem and cerebellum.
    Dorsal Root Ganglion
    Contains sensory neuron cell bodies.
    Cervical Plexus
    Network of nerves supplying neck and shoulder.

    Filum Terminale

    Reviewed by our medical team

    Fibrous extension from conus to coccyx.

    1. Overview

    The filum terminale is a delicate, thread-like structure that extends from the conus medullaris, the tapered end of the spinal cord, to the coccyx (tailbone). It is a part of the spinal cord's anchoring system and plays a crucial role in stabilizing the spinal cord within the vertebral column. The filum terminale is composed of fibrous tissue and the pia mater, one of the meninges that protect the central nervous system. It serves as an important stabilizing element, helping to prevent excessive movement of the spinal cord within the spinal column, particularly in the lower back.

    2. Location

    The filum terminale is located at the base of the spinal cord, specifically extending from the conus medullaris, which is situated near the level of the first or second lumbar vertebra (L1-L2) in adults. It extends downward through the lumbar and sacral regions, passing through the sacral canal and terminating at the coccyx. The filum terminale is within the spinal dural sac, the protective covering that surrounds the spinal cord and the cauda equina (the bundle of nerve roots extending from the conus medullaris). It is situated along the midline, providing support to the spinal cord.

    3. Structure

    The filum terminale is a long, thin structure composed primarily of connective tissue, with components of the pia mater that extend beyond the spinal cord. The key structural features of the filum terminale include:

    • Pia mater composition: The filum terminale is largely made up of pia mater, which is the innermost layer of the meninges that directly covers the spinal cord and brain. Pia mater is a delicate, highly vascular membrane that helps to anchor the spinal cord and maintain its stability.

    • Fibrous tissue: The filum terminale contains fibrous tissue, which provides additional support and structure to the spinal cord. This tissue helps the filum terminale to act as an anchor, securing the spinal cord in place.

    • Length and attachment: The filum terminale extends from the conus medullaris to the coccyx. It measures approximately 20-22 centimeters in length in adults and is attached to the coccyx at its distal end. It passes through the dural sac, which contains the cauda equina.

    • Two parts: The filum terminale can be divided into two parts: the filum terminale internum and the filum terminale externum. The filum terminale internum is the portion inside the dural sac that extends from the conus medullaris to the point where the dura mater ends. The filum terminale externum extends beyond the dural sac, passing through the sacral canal to attach to the coccyx.

    4. Function

    The primary function of the filum terminale is to provide stability and anchorage to the spinal cord, preventing it from excessive movement within the spinal column. It plays a role in the following functions:

    • Anchoring the spinal cord: The filum terminale secures the spinal cord to the coccyx, ensuring that the spinal cord remains stable and does not shift or move excessively within the vertebral column. This function is important for maintaining the integrity of the spinal cord, particularly in response to movement or physical stress.

    • Preventing tension: The filum terminale helps prevent excessive tension on the spinal cord. The spinal cord is a highly sensitive structure, and any movement that places undue stress on it could result in injury. By stabilizing the spinal cord, the filum terminale reduces the risk of damage from strain or displacement.

    • Support for the cauda equina: The filum terminale also helps support the cauda equina, the bundle of nerve roots that extend from the conus medullaris. By anchoring the spinal cord and the cauda equina, the filum terminale provides structural support to the lower spinal cord and nerve roots, which are essential for the function of the lower body.

    5. Physiological Role(s)

    The physiological roles of the filum terminale are essential for the normal functioning of the spinal cord and the stability of the central nervous system:

    • Spinal cord stabilization: The filum terminale plays a key role in stabilizing the spinal cord within the vertebral column, preventing excessive movement or stretching of the spinal cord. This stabilization is crucial for maintaining the alignment and protection of the neural tissue, particularly during physical activities or changes in posture.

    • Support for spinal cord function: By preventing movement of the spinal cord, the filum terminale helps ensure the proper transmission of signals between the brain and the body. Any displacement or damage to the spinal cord could lead to functional impairments, such as loss of motor function or sensory deficits. The filum terminale helps mitigate these risks by providing structural support.

    • Protection of nerve roots: The filum terminale also plays a protective role for the cauda equina, which contains the nerve roots responsible for motor and sensory functions in the lower body. By stabilizing these structures, the filum terminale ensures that the cauda equina can function properly without being subjected to excessive mechanical stress.

    6. Clinical Significance

    The filum terminale is clinically significant because any abnormalities or damage to this structure can lead to serious neurological issues. Some clinical conditions related to the filum terminale include:

    • Tethered spinal cord syndrome: Tethered cord syndrome is a condition in which the filum terminale becomes abnormally thickened or shortened, leading to the "tethering" of the spinal cord. This can cause the spinal cord to be pulled or stretched, leading to symptoms such as back pain, leg weakness, bladder and bowel dysfunction, and sensory changes in the lower body. Tethered cord syndrome is often diagnosed in childhood but can also occur in adulthood.

    • Spinal cord injury: Damage to the filum terminale or surrounding structures can lead to complications such as spinal cord instability or herniation. If the filum terminale is disrupted, it can affect the stability of the spinal cord, potentially leading to damage in the lower parts of the body, including loss of sensation or motor function in the legs.

    • Congenital abnormalities: Abnormalities in the development of the filum terminale can result in tethered cord syndrome or other malformations. These abnormalities may affect the length, structure, or attachment of the filum terminale, leading to dysfunction in spinal cord or nerve root function.

    • Post-surgical complications: In certain spinal surgeries, particularly those involving the lower back, the filum terminale may be affected, leading to unintended stretching or tension of the spinal cord. This can result in complications such as nerve damage, pain, and functional impairments. Surgical procedures to treat tethered cord syndrome often involve the release or untethering of the filum terminale.

    The filum terminale plays an essential role in maintaining the stability of the spinal cord and preventing excessive movement that could lead to injury. Abnormalities in the filum terminale can lead to serious conditions, such as tethered cord syndrome, which can cause neurological deficits and impair quality of life. Early diagnosis and appropriate surgical intervention are critical for managing conditions related to the filum terminale and preventing long-term complications.

    Did you know? Neurons communicate with each other using electrical signals called action potentials.