Filum terminale

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Filum terminale
Cauda equina and filum terminale seen from behind. The dura mater has been opened and spread out, and the arachnoid has been removed. (Filum terminale labeled at center right.)
Sagittal section of vertebral canal to show the lower end of the medulla spinalis and the filum terminale. Li, Lv. First and fifth lumbar vertebra. SII Second sacral vertebra. 1. Dura mater. 2. Lower part of subarachnoid cavity. 3. Lower extremity of medulla spinalis. 4. Filum terminale internum. 5. Filum terminale externum. 6. Attachment of filum terminale to first segment of coccyx.
Gray's	subject #185 750
Dorlands/Elsevier	f_07/12364942

The filum terminale is a delicate filament, about 20 cm. in length, prolonged downward from the apex of the conus medullaris.

It consists of two parts, an upper and a lower.

• The upper part, or filum terminale internum, measures about 15 cm. in length and reaches as far as the lower border of the second sacral vertebra. It is contained within the tubular sheath of dura mater, and is surrounded by the nerves forming the cauda equina, from which it can be readily recognized by its bluish-white color.

• The lower part, or filum terminale externum, is closely invested by, and is adherent 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.

The filum terminale consists mainly of fibrous tissue, continuous above with that of the pia mater.

Adhering to its outer surface, however, are a few strands of nerve fibers which probably represent rudimentary second and third coccygeal nerves; further, the central canal of the medulla spinalis extends downward into it for 5 or 6 cm.

[edit] See also

• Spinal cord

[edit] External links

• Dictionary at eMedicine terminal+filum
• MedEd at Loyola grossanatomy/dissector/practical/back/back2.html
• Norman/Georgetown lesson6spinalcord&coverings
• SUNY Labs 02:08-0104 - "Vertebral Canal and Spinal Cord: Regions of the Spinal Cord"
• Roche Lexicon - illustrated navigator, at Elsevier 03281.000-1

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e Anatomy of torso (primarily): the spinal cord

epidural space, dura mater, subdural space, arachnoid mater, subarachnoid space, pia mater, denticulate ligaments conus medullaris, cauda equina, filum terminale, cervical enlargement, lumbar enlargement, anterior median fissure spinal nerve: dorsal root, dorsal root ganglion, dorsal ramus, ventral root, ventral ramus, sympathetic trunk, ramus communicans (gray, white) gray matter: central canal, substantia gelatinosa of Rolando, reticular formation, substantia gelatinosa centralis, interneuron, anterior horn, lateral horn, posterior horn (column of Clarke, dorsal spinocerebellar tract) white matter: anterior funiculus: descending (anterior corticospinal tract, vestibulospinal fasciculus, tectospinal tract), ascending (anterior spinothalamic tract, anterior proper fasciculus) lateral funiculus: descending (lateral corticospinal tract, rubrospinal tract, olivospinal tract), ascending (dorsal spinocerebellar tract, ventral spinocerebellar tract, spinothalamic tract, lateral spinothalamic tract, anterior spinothalamic tract, spinotectal tract, posterolateral tract, lateral proper fasciculus, medial longitudinal fasciculus posterior funiculus: fasciculus gracilis, fasciculus cuneatus, posterior proper fasciculus