Spinal cord
Spinal cord
- Located in a canal within the vertebral column that affords it structural support.- Rostrally it continues to the medulla oblongata of the brain and caudally it tapers at a level corresponding to the L1-2 interspace (in the adult), a central structure, the filum terminale anchors the cord to the first coccygeal vertebra.
- The spinal cord is characterised by cervico-lumbar enlargements and these, broadly speaking, are the sites which correspond to the brachial and lumbar plexuses respectively.
There are some key points to note when considering the surgical anatomy of the spinal cord:
* During foetal growth the spinal cord becomes shorter than the spinal canal, hence the adult site of cord termination at the L1-2 level.
* Due to growth of the vertebral column the spine segmental levels may not always correspond to bony landmarks as they do in the cervical spine.
* The spinal cord is incompletely divided into two symmetrical halves by a dorsal median sulcus and ventral median fissure. Grey matter surrounds a central canal that is continuous rostrally with the ventricular system of the CNS.
* The grey matter is sub divided cytoarchitecturally into Rexeds laminae.
* Afferent fibres entering through the dorsal roots usually terminate near their point of entry but may travel for varying distances in Lissauers tract. In this way they may establish synaptic connections over several levels
* At the tip of the dorsal horn are afferents associated with nociceptive stimuli. The ventral horn contains neurones that innervate skeletal muscle.
The key point to remember when revising CNS anatomy is to keep a clinical perspective in mind. So it is worth classifying the ways in which the spinal cord may become injured. These include:
- Trauma either direct or as a result of disc protrusion
- Neoplasia either by direct invasion (rare) or as a result of pathological vertebral fracture
- Inflammatory diseases such as Rheumatoid disease, or OA (formation of osteophytes compressing nerve roots etc.
- Vascular either as a result of stroke (rare in cord) or as complication of aortic dissection
- Infection historically diseases such as TB, epidural abscesses.
The anatomy of the cord will, to an extent dictate the clinical presentation. Some points/ conditions to remember:
- Brown- Sequard syndrome-Hemisection of the cord producing ipsilateral loss of proprioception and upper motor neurone signs, plus contralateral loss of pain and temperature sensation. The explanation of this is that the fibres decussate at different levels.
- Lesions below L1 will tend to present with lower motor neurone signs
+PassMedicine Notes
- Rostrally it continues to the medulla oblongata of the brain and caudally it tapers at a level corresponding to the L1-2 interspace (in the adult), a central structure, the filum terminale anchors the cord to the first coccygeal vertebra.
- The spinal cord is characterised by cervico-lumbar enlargements and these, broadly speaking, are the sites which correspond to the brachial and lumbar plexuses respectively.
There are some key points to note when considering the surgical anatomy of the spinal cord:
* During foetal growth the spinal cord becomes shorter than the spinal canal, hence the adult site of cord termination at the L1-2 level.
* Due to growth of the vertebral column the spine segmental levels may not always correspond to bony landmarks as they do in the cervical spine.
* The spinal cord is incompletely divided into two symmetrical halves by a dorsal median sulcus and ventral median fissure. Grey matter surrounds a central canal that is continuous rostrally with the ventricular system of the CNS.
* The grey matter is sub divided cytoarchitecturally into Rexeds laminae.
* Afferent fibres entering through the dorsal roots usually terminate near their point of entry but may travel for varying distances in Lissauers tract. In this way they may establish synaptic connections over several levels
* At the tip of the dorsal horn are afferents associated with nociceptive stimuli. The ventral horn contains neurones that innervate skeletal muscle.
The key point to remember when revising CNS anatomy is to keep a clinical perspective in mind. So it is worth classifying the ways in which the spinal cord may become injured. These include:
- Trauma either direct or as a result of disc protrusion
- Neoplasia either by direct invasion (rare) or as a result of pathological vertebral fracture
- Inflammatory diseases such as Rheumatoid disease, or OA (formation of osteophytes compressing nerve roots etc.
- Vascular either as a result of stroke (rare in cord) or as complication of aortic dissection
- Infection historically diseases such as TB, epidural abscesses.
The anatomy of the cord will, to an extent dictate the clinical presentation. Some points/ conditions to remember:
- Brown- Sequard syndrome-Hemisection of the cord producing ipsilateral loss of proprioception and upper motor neurone signs, plus contralateral loss of pain and temperature sensation. The explanation of this is that the fibres decussate at different levels.
- Lesions below L1 will tend to present with lower motor neurone signs
