2- spinal cord general topography and internal structure - week 1

Question 1

Where dose the spine cord begin and where dose it end ?

Answer 1

• Begins at:Foramen magnum
• Ends at: L3 (newborn), L1 (adult)

Question 2

What is the length of the spinal chord in males ?

Answer 2

About 45 cm and it is long in males

Question 3

What is superior of the spinal cord ?

Answer 3

Medulla obongata

Question 4

What are the two enlargements of the spinal cord ?

Answer 4

• cervical enlargement
• lumbar enlargement

Question 5

Where is the cervical enlargement ?

Answer 5

– The region where Spinal nerves form the brachial plexus
– Diameter, about 38 mm

Question 6

Where is the lumbar enlargement ?

Answer 6

– 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)

Question 7

Where is the conus medullaris & cauda equina ?

Answer 7

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.

Question 8

What are meninges ?

Answer 8

They are membranes that surround the spinal cord

Question 9

What are denticulate ligament ?

Answer 9

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

Question 10

What are the external features of the spinal cord ?

Answer 10

• Anterior median fissure
• Posterior median sulcus
• Anterolateral sulcus
• Posterolateral sulcus(dorsolat.

Question 11

What is the spinal cord segment ?

Answer 11

It is part of Spinal Cord from where a pair of Spinal Nerves, where one arise from right & one from left side.

Question 12

How many segments are there in the spinal nerves and how are they divided ?

Answer 12

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

Question 13

Where is the posterior root of the spinal nerve and what is its function ?

Answer 13

enters spinal cord from posterolateral sulcus, It brings sensory information from periphery.

Question 14

Where is the anterior root of the spinal nerve and what dose it do ?

Answer 14

It leaves the spinal cord from anterolateral sulcus, motor, Fila radicularia (rootlets) the fibres forming the anterior and posterior roots Spinal nerve.

Question 15

Where is the spinal cord located at ?

Answer 15

Its located in the vertebral canal.

Question 16

How dose the Spinal nerves leave the
vertebral canal ?

Answer 16

by passing through the intervertebral foramen

Question 17

Why are there is 8 pairs of the spinal nerves at the cervicval level ?

Answer 17

Because the C! Spinal nerve (suboccipital nerves ) levels the vertebrate canal between the atlas and occipital bone.

Question 18

What is the dermatome ?

Answer 18

It is the skin region innervated by one spinal nerve .

Question 19

What is the axial line ?

Answer 19

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.

Question 20

What happens by the axial line ?

Answer 20

The nerve fibers innervating the two
neighbouring dermatomes do not pass to each other.

Question 21

What is the gray matter in the internal structure of the spinal cord ?

Answer 21

contains Neurons, neuroglia and blood vessels and its Butterfly shaped .

Question 22

What is the white matter in the internal structure of the spinal cord and what is its parts ?

Answer 22

It contains nerve fibers, neuroglia and blood vessels
Its parts are :
– Anterior funiculus
– Posterior funiculus
– Lateral funiculus

Question 23

What dose the gray matter have ?

Answer 23

• Anterior horn
• Posterior horn
• Lateral horn (between the T1- L3 )

Question 24

What dose the gray matter have in the examination of the spinal cord (3D) ?

Answer 24

• anterior column
• posterior column
• lateral column (columna intermedia)

Question 25

What dose the central canal contain ?

Answer 25

It contains cerebrospinal fluid.

Question 26

What is in the anterior and posterior aspect to the central canal ?

Answer 26

- Anterior gray commissure - Posterior gray commissure

Question 27

Where is the central canal ?

Answer 27

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).

Question 28

How many laminae is in the gray matter ?

Answer 28

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.

Question 29

Where is the White matter is formed by axon located in ?

Answer 29

- 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

Question 30

What are spinal reflexes ?

Answer 30

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

Question 31

What is in the anterior aspect of the spinal cord ?

Answer 31

It is located in the subarachnoidal space : Vertebral arteries and radical nerves

Question 32

What is the vertebral artery ?

Answer 32

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.

Question 33

What are radical arteries ?

Answer 33

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.

Question 34

Where dose the spinal branches course along ?

Answer 34

The spinal nerves, they Pass through intervertebral foramina and divide into anterior and posterior radicular arteries .

Question 35

How is the arterial vascorona formed ?

Answer 35

Anastomose with ant+post spinal arteries

Question 36

What is the artery of the adamkiewicz ?

Answer 36

- 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.

Question 37

What are the veins of the spinal cord ?

Answer 37

- 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).

Question 38

Where are the connections of the epidural venous plexus ?

Answer 38

- 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