NEUROANATOMY - SPINAL CORD EXTERNAL FEATURES - BY DR MITESH DAVE

Overview of the Spinal Cord

Structure and Location

• The spinal cord, also known as the spinal medulla, is approximately 45 centimeters (18 inches) long and lies within the vertebral canal.

• It extends from the foramen magnum at the upper border of the atlas vertebra to the lower border of the first lumbar vertebra (L1) in adults.

Conus Medullaris and Filum Terminale

• The tapering end of the spinal cord is called the conus medullaris, which marks its lower termination.

• Attached to the apex of conus medullaris is a fibrous structure known as filum terminale, a continuation of pia mater.

Filum Terminale Internum and Externum

• The filum terminale internum extends from L1 to S2 vertebra where subarachnoid space ends.

• Beyond S2 to coccyx, it becomes filum terminale externum, surrounded by dural sheath but lacking subarachnoid space.

Modifications of Pia Mater

Ligamenta Denticulata

• On each side of the spinal cord are thickened areas called ligamenta denticulata that help suspend it in place.

• There are 21 pairs of these triangular tooth-like processes located between ventral and dorsal nerve roots.

Linear Splendens

• Another modification is linear splendens, a thickening along the anterior median fissure appearing as a glistening white band.

• This structure runs alongside an important blood vessel known as anterior spinal artery located in this fissure.

Posterior Surface Features

Sulci and Arteries

• The posterior surface features include posterior median sulcus and posterolateral sulcus where rootlets attach on either side.

• Alongside these sulci are posterior spinal arteries present on each side.

Transverse Section Insights

Grey Matter Structure

• A transverse section reveals H-shaped grey matter; broader parts form ventral horns while slender parts form dorsal horns.

• Surrounding this grey matter is white matter, highlighting key structural features essential for understanding spinal cord anatomy.