The filum terminale ("terminal thread") is a delicate strand of
fibrous tissue
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorpora ...
, about 20 cm in length, proceeding downward from the apex of the
conus medullaris
''Conus'' is a genus of predatory sea snails, or cone snails, marine gastropod mollusks in the family Conidae.Bouchet, P.; Gofas, S. (2015). Conus Linnaeus, 1758. In: MolluscaBase (2015). Accessed through: World Register of Marine Species ...
. It is one of the modifications of
pia mater
Pia mater ( or ),[Entry "pia mater"](_blank)
in
spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spin ...
and consists of two parts:
* The upper part, or filum terminale internum, is about 15 cm long and reaches as far as the lower border of the second
sacral vertebra. It is continuous above with the
pia mater
Pia mater ( or ),[Entry "pia mater"](_blank)
in
dura mater
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous syste ...
. In addition, it is surrounded by the nerves forming the
cauda equina, from which it can be easily recognized by its bluish-white color.
* The lower part, or filum terminale externum, closely adheres to the dura mater. It extends downward from the apex of the tubular sheath and is attached to the back of the first segment of the
coccyx in a structure sometimes referred to as the ''coccygeal ligament''.
The most
inferior
Inferior may refer to:
* Inferiority complex
* An Anatomical terms of location#Superior and inferior, anatomical term of location
* Inferior angle of the scapula, in the human skeleton
*Inferior (book), ''Inferior'' (book), by Angela Saini
* ''The ...
of the spinal nerves, the
coccygeal nerve leaves the spinal cord at the level of the conus medullaris via respective vertebrae through their intervertebral foramina,
superior
Superior may refer to:
*Superior (hierarchy), something which is higher in a hierarchical structure of any kind
Places
*Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state
*Lake ...
to the filum terminale. However, adhering to the outer surface of the filum terminale are a few strands of
nerve fibres which probably represent rudimentary second and third coccygeal nerves.
Furthermore, the
central canal of the spinal cord extends 5 to 6 cm beyond the conus medullaris, downward into the filum terminale.
Additional Images
File:Slide3dsdd.GIF, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide5sese.GIF, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide6drdr.GIF, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide4rer.JPG, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide5rer.JPG, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide6rer.JPG, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
File:Slide7feer.JPG, Spinal cord. Spinal membranes and nerve roots.Deep dissection. Posterior view.
References
* Martini, F. Timmons, M. and Tallitsch, R. ''Human Anatomy''. 5th ed. San Francisco: Pearson/Benjamin Cummings, 2006.
External links
*
*
* - "Vertebral Canal and Spinal Cord: Regions of the Spinal Cord"
*
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Meninges