2- spinal cord general topography and internal structure - week 1 Flashcards
Where dose the spine cord begin and where dose it end ?
- Begins at:Foramen magnum
- Ends at: L3 (newborn), L1 (adult)
What is the length of the spinal chord in males ?
About 45 cm and it is long in males
What is superior of the spinal cord ?
Medulla obongata
What are the two enlargements of the spinal cord ?
- cervical enlargement
- lumbar enlargement
Where is the cervical enlargement ?
– The region where Spinal nerves form the brachial plexus
– Diameter, about 38 mm
Where is the lumbar enlargement ?
– The region where Spinal nerves form the lumbosacral plexus
– Diameter, about 35 mm
– After lumbar enlargement it becomes thin and forms conus medullaris ( this is the lower end of Spinal cord)
Where is the conus medullaris & cauda equina ?
The Spinal cord narrows below after lumbosacral enlargement, Conus medullaris ; is the at thelower end of spinal cord, Cauda equina (pony tail):Below conus medullaris Roots of spinal nerves Surrounding the filum terminale.
What are meninges ?
They are membranes that surround the spinal cord
What are denticulate ligament ?
Spinal cord is suspended within dural sac by denticulate ligaments on
each side; It is the Extension of pia mater; 20 – 22 in number ,With arachnoid mater attaches to the inner surface of dural sac
What are the external features of the spinal cord ?
- Anterior median fissure
- Posterior median sulcus
- Anterolateral sulcus
- Posterolateral sulcus(dorsolat.
What is the spinal cord segment ?
It is part of Spinal Cord from where a pair of Spinal Nerves, where one arise from right & one from left side.
How many segments are there in the spinal nerves and how are they divided ?
There are 31 segments divided into :
- 8 in cervical region
- 12 in thoracic region
- 5 in lumbar region
- 5 in sacral region
- 1 in coccygeal region
Where is the posterior root of the spinal nerve and what is its function ?
enters spinal cord from posterolateral sulcus, It brings sensory information from periphery.
Where is the anterior root of the spinal nerve and what dose it do ?
It leaves the spinal cord from anterolateral sulcus, motor, Fila radicularia (rootlets) the fibres forming the anterior and posterior roots Spinal nerve.
Where is the spinal cord located at ?
Its located in the vertebral canal.
How dose the Spinal nerves leave the
vertebral canal ?
by passing through the intervertebral foramen
Why are there is 8 pairs of the spinal nerves at the cervicval level ?
Because the C! Spinal nerve (suboccipital nerves ) levels the vertebrate canal between the atlas and occipital bone.
What is the dermatome ?
It is the skin region innervated by one spinal nerve .
What is the axial line ?
It is in regions of the spinal nerves innervating the two neighboring dermatome areas that don’t originate from the neighboring segments of the line between this type of two dermatome regions.
What happens by the axial line ?
The nerve fibers innervating the two
neighbouring dermatomes do not pass to each other.
What is the gray matter in the internal structure of the spinal cord ?
contains Neurons, neuroglia and blood vessels and its Butterfly shaped .
What is the white matter in the internal structure of the spinal cord and what is its parts ?
It contains nerve fibers, neuroglia and blood vessels
Its parts are :
– Anterior funiculus
– Posterior funiculus
– Lateral funiculus
What dose the gray matter have ?
- Anterior horn
- Posterior horn
- Lateral horn (between the T1- L3 )
What dose the gray matter have in the examination of the spinal cord (3D) ?
- anterior column
- posterior column
- lateral column (columna intermedia)
What dose the central canal contain ?
It contains cerebrospinal fluid.
What is in the anterior and posterior aspect to the central canal ?
- Anterior gray commissure
- Posterior gray commissure
Where is the central canal ?
Its Within the gray matter,all along the spinal cord and caudal half of medulla oblongata, it opens above into the 4th ventricle.
In the consensus medullaris it expands as a fusiform terminal ventricle as it contains cerebrospinal fluid (CSF).
How many laminae is in the gray matter ?
10 laminae, depending upon to dimension, shape, cellular charactraistics and the density of the neurons .
- Laminae I – IV (post. horn): are related to sensory pathways
(afferent pathways)
- Lamina IX (ant. Horn): contains alpha motor neurons, gamma motor neurons and intraneurons.
Where is the White matter is formed by axon located in ?
- Posterior funiculus; in cervical and upper thoracic segments, has dorsal-intermediate sulcus; divided into fasciculus gracilis (medial) and fasciculus cunertus (lateral).
- Lateral funiculus
- Anterior funiculus
- anterior white commissure
- posterior white commissure
What are spinal reflexes ?
coming from receptors in the muscles, joints and skin reach to the post horn neurons They do not reach the cortical areas Fibers directly arise from alfa motor neurons (lamina IX) and form involuntary movements
What is in the anterior aspect of the spinal cord ?
It is located in the subarachnoidal space :
Vertebral arteries and radical nerves
What is the vertebral artery ?
It is a Branch of subclavian artery, it Passes through foramina of all cervical transverse processes, except 7th.
It Enters cranium through foramen magnum and it gives :
- Posterior spinal artery(2 in
number)
- Anterior spinal artery (1 in number)
* 2 anterior spinal arteries Unite ,form single anterior spinal artery.
What are radical arteries ?
They are the Spinal branches of Neighboring
arteries during the course of spinal cord namely:
-Ascending cervical artery.
-Deep cervical artery.
-Intercostal arteries.
-Lumbar arteries.
-Lateral sacral arteries.
Where dose the spinal branches course along ?
The spinal nerves, they Pass through intervertebral foramina and divide into anterior and
posterior radicular arteries .
How is the arterial vascorona formed ?
Anastomose with ant+post spinal arteries
What is the artery of the adamkiewicz ?
- In the lumbar region, on the left side, one of the anterior radicular branches has a greater caliber than the others.
- On the left side of spinal cord, supplies blood to lower thoracic and upper lumbar regions (main artery.
What are the veins of the spinal cord ?
- Anterior spinal vein.
- Posterior spinal vein.
- Venous vasocorona
- These vein unite and drain into ant and post radicular veins.
- Ant, post radicular veins. → ant and post internal vertebral venous plexuses (epidural venous plexus).
Where are the connections of the epidural venous plexus ?
- Thoracal veins.
- Abdominal veins.
- Intercostal veins.
- Ant external vertebral venous plexus
- Post external vertebral venous plexus
- Prostatic venous plexus
- Pelvic venous plexus
- at the level of foramenmagnum, ant and post
internal vertebral venous plexuses give branches,
which connect with vertebral
v., sigmoid sinus, occipi
