anatomy 5.pdf

7/29/2019 anatomy 5.pdf

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Today we will talk about the vertebral columnspecifically thecervical part of it :

We will talk firstly about the general structure of the vertebralcolumn.

The vertebral column is the lower part of the axial skeleton forming

the skeleton for the neck and the back and it is made of 33 vertebrae:

7 cervical.12 thoracic.5 lumbar.5 sacral (they fuse together into one piece; we refer to it as thesacrum).

4 coccygeal (they fuse together into one piece; we refer to it asthe coccyx).


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In between these bones (vertebrae) there is a cartilaginous disc

known as the intervertebral disc (IV) , they are present there to

facilitate the movement between these vertebrae and providing

resilience to the vertebral column to allow for the movement of thetrunk.

How many IV disc are there?

We have 23 IV disc:

Between the 1st

and 2nd

vertebrae there are no disc, the sacrum and

the coccyx they are fused so there is no IV disc.

When we look in a saggital view we notice that the vertebral column

is not straight, its curved (there are curvatures).

These normal curvatures of the vertebral column, they are important

in permitting the movement and weight bearing of the trunk.

We have two types of normal curvatures:

The primary (which begins firstly):Usually start to develop during fetal life inside the uterus , when the

fetus is shrunken on himself , the whole vertebral column is concaved

anteriorly.


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After birth this anterior concavity remains only in two regions of the

vertebral column (the thoracic and the sacral), so in the thorax

and in the sacrum we still have the primary curvatures of the

vertebral column.

* Secondary curvatures:

After birth, during the age of (3-6) month usually when the child start

to rise his head (when he start to hold his head erect), this will change

the concavity in the cervical region to concaved posteriorly, whenhe start to walk and assumes his upright posture (8-12) month so the

curvature will change in the lumbar region to posterior concavity.

So we have 2 primary curvatures which appear in the thoracicand the sacral regions and 2 secondary curvatures in the cervical

and the lumbar regions.
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Additionally we have some abnormal curves of the vertebral column

1-Kyphosis: we refer to it as the hunch back, this is usuallyhappens in old people (geriatric people) who are suffering from

osteoporosis, they will have erosion in the anterior part of the

vertebrae (in the thoracic region).

2-Lordosis: we refer to it as the hollow back, this is increase inthe lumbar curvatures, lordosis happens because of weakness in

the abdominal musculatures (anteriolateral abdominal muscles;

external oblique and the internal oblique, which holds the

vertebral column posterior with the anterior abdominal wall) or

it can happen temporarily in late pregnant female to

compensate and bear the weight of the fetus.

3-Scoliosis : the most common one in pubertal females , we referto it as the curved back , this is a lateral curvature, scoliosismay happens because of asymmetrical paralysis of intrinsic back

muscle one side only so the muscle at the other side is going

to pull the vertebral column to its side myopathic scoliosis, or

it could happen because of difference in the length of the lower

limb congenital, sometimes failure of half of vertebra to

develop they called it hemi vertebrae scoliosis.


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So, lets summarize the abnormal curvatures:

1-Kyphosis increased thoracic curvature.

2-Lordosis increased lumbar curvature.
http://www.google.jo/url?sa=i&rct=j&q=lordosis&source=images&cd=&cad=rja&docid=T7ICIswPqzMrrM&tbnid=5f1el1FIdSKeAM:&ved=0CAUQjRw&url=http://stronglifts.com/lordosis-why-it-causes-lower-back-pain-how-to-fix-it/&ei=1PAhUZOZLI_BtAagnoGgBA&psig=AFQjCNGbT1x5yF9SuudbqS0UqljfhB7HHw&ust=1361265230227335http://www.google.jo/url?sa=i&rct=j&q=kyphosis&source=images&cd=&cad=rja&docid=ksGHW4ETS-3eZM&tbnid=NvyvWmfNVi2pRM:&ved=0CAUQjRw&url=http://uprightdoctor.wordpress.com/2011/07/08/kyphosis-stenosis-and-multiple-sclerosis/&ei=QvAhUdDFNtDNsgaMkIHIBw&psig=AFQjCNFA6CTLRMGcrvOG0Y3j286-hLFJoQ&ust=1361265086250958


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3-Scoliosis lateral curvature in thevertebral column.

We will now talk about the IV disc we said that those discs arecartilaginous, so we refer to the joint between the vertebrae as

cartilaginous joint this mean that there are limited movement

not free movement as the synovial nor as the fibrous that has

no movement at all.

Those discs are made of 2 part :

Annulus fibrosus: The outer part which is a concentric circularlayer of fibrocartilage, it is there to protect the inner core of the

disc nucleus pulposus and to Strengthens the disc.

Nucleus pulposus: The central core of the disc and it is thegelatinous material within the disc, which is responsible for

increasing the elasticity of the disc so it acts as a shock absorber

between the vertebrae.
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If we look to any disc we see that the annulus fibrosus layer from

back is much thinner than anteriorly, so if there is any tear in the disc

because of the pressure on the disc so this will pressure the nucleus

pulposus, this pressure will be exerted anteriorly and posteriorly and

also laterally, the weakest area is the posterior area of the disc, sothere will be tearing in annulus fibrosis and a leakage of the nucleus

pulposus to the outside this is what we refer as the disc herniation,

when it goes posteriorly there will be the spinal cord , so this will

pressure on the spinal cord and this will produce the back pain.

The most common area to have back herniation is the lowest twodiscs because the largest weight is on them, between the (L4-L5)

Or between (L5-S1), we all know that at the level of L4-L5 we have

spinal nerves that participate in the largest nerve in our body sciatic

nerve which has a root value of (L4-S3) so if there is a disc herniation

in these areas there will be a leakage of nucleus pulposus and this

leakage will produce pressure on the spinal cord and spinal nervesthere, this pain will start to radiate from the root of these spinal

nerves along with their continuation the sciatic nerve all along the

back of the leg which we refer as the sciatica.


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Now we will talk about the IV ligaments which fix the discs on each

other, we have anterior and posterior ligaments:

Anteriorly we have a very broad and thick strong ligamentextends anteriolaterally along the vertebrae and the discs from

the beginning of the vertebral column all the way down to the

sacrum this is called anterior longitudinal ligament

covering the whole anteriolateral aspect of the vertebral

column.

Posteriorly we have another ligament but it is much thinner andweaker covering only the middle part of posterior aspect of thevertebral bodies, this is called posterior longitudinal

ligament.

In addition to them there are ligaments supporting the arches (the

arch is formed by two pedicles and two laminae):

Between the transverse processes we call it Intertransverseligament.

Between the spinous processes we call it Interspinousligament.

At the tip of the spinous processes we call it supraspinousligament.

Between the laminae we call it Ligamentum flavum or Flavaligaments, they are joining the laminae with each other, they

call it Flava which is a Latin word that means yellowish because

they are made up of elastic fibers, so they are very elastic.


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Now we have a very important ligament at the region of the neck

Nuchal ligament it is an additional ligament for the vertebral

column but its just in the neck, Nucha is a French word that means

the back of the neck whereas occipit is a Latin word that means theback of the head.

This ligament start from the external occipital protuberance, itextends from there and as it descend down it forms a linear

elevation form the external occipital protuberance to the

posterior margin of foramen magnum which we call external

occipital crest or median nuchal line, then it descend down

and merge with the supraspinous ligaments and the tips of the

spinous processes all the way down until C7 providing a very

important support to the back of the neck.

Now we will talk about the main topic of the lecture the cervical

vertebrae:

They can be classified as typical and atypical vertebrae according to

the absence or additional characteristics that they posses ..

We have 7 processes for each vertebra:

Spinous, 2 transverse, 2 superior articular and 2 inferiorarticular.


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What are the characteristics to have a typical cervical

vertebra?

In the cervical vertebrae the body is usually small andrectangular in shape whereas in the thoracic the body is heart

shaped and in the lumbar kidney shaped.

There are transverse foramina in the transverse processes; thoseforamina are not present in the thoracic or the lumbar

vertebrae, those foramina protects and allows for the vertebral

artery which is a branch from the subclavian artery to pass

through these foramina all the way up into the skull but as soon

as it branch from the subclavian artery it will be too close to C7

so this artery will not pass through the transverse foramen of C7

instead it pass anterior to C7, so this artery will pass through the

transverse foramina of (C6-C1) and then it will enter the


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foramen magnum inside the skull where the two vertebral

arteries form both sides will fuse together into one large artery

basilar artery which supply the brain stem and the inferior

aspect of the brain.

So the brain receives its blood supply by the:

Internal carotid arteries which supplies the superioanterioraspect of the brain.

The two vertebral arteries which fuse to form the basilar arterythat supplies the brain stem and the inferioposterior aspect ofthe brain.

So C7 does have a transverse foramina but the vertebral artery

doesnt pass through them to prevent the sharp angulation therefore

avoid the blockage of this artery so this is the first exception that

make C7 atypical vertebra.
http://www.google.jo/url?sa=i&rct=j&q=basilar%20artery&source=images&cd=&cad=rja&docid=U-LYTw05EySUsM&tbnid=uOUJ7hY6xXxjTM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.columbianeurosurgery.org%2F2010%2F08%2Fsolomon-giant-aneurysms%2F&ei=6wgiUe_1KM62hAe20ICYDw&psig=AFQjCNEYpn0orKy78T-rOC-sZKc_OzUdDw&ust=1361271387469523


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Short bifid spine, what we mean by bifid is that the tip of thespinous process has two head, the exception here is also C7

which has a long one and it isnt bifid (only one head), and you

can easily feel this bony prominence at the root of the neckposteriorly, this bony prominence indicates the spinous process

of C7 and its used by the physician to count vertebrae.

Their vertebral foramina in which the spinal cord pass are verylarge and triangular in shape; the vertebral foramen as we move

down, it get much smaller and sharper, so the biggest vertebral

foramen we can see is in the cervical region the it get smaller in

the thoracic and even much smaller in the lumbar and the sacral

regions.

So these are the 4 main characteristics of the typical cervical

vertebrae:

Small rectangular body.

Transverse foramina.

Short bifid spines.

Large vertebral foramen.


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So we have typical and atypical cervical vertebrae:

C1, C2 and C7 are atypical vertebrae. C3, C4, C5, C5 are typical vertebrae.

So what makes C7 atypical vertebra:

1-It has a transverse foramina but the vertebral arteries doesnt pass

through them instead the vertebral vein does.

2-The spinous process is long and not bifid.

This is a picture of C7.
http://www.google.jo/url?sa=i&rct=j&q=c7+vertebra&source=images&cd=&cad=rja&docid=VfYc4FLkoqW4VM&tbnid=70Mf5k7zsNQPgM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.daviddarling.info%2Fencyclopedia%2FC%2Fcervical_vertebra.html&ei=-hciUdiZGMSZhQee6IHYBg&psig=AFQjCNEka5y845QysHUEbzHJcek_v-BOSQ&ust=1361275248306675


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Now we will talk about the 1st cervical vertebrae C1 (Atlas):

Why C1 is atypical:

There is no body. No spinous process instead it has tubercle (posterior tubercle). Anterior arch and posterior arch Two small masses of bones laterally located they call them the

lateral masses of Atlas to provide articulation of Atlas superiorly

with the skull through Atlanto-Occipital joint; it articulate withthe condyles of the occipital bone, and inferiorly Atlas articulate

with the 2nd

cervical vertebra C2 Axis through

Atlanto-Axial joint.


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The name Atlas comes from the Greek mythology the Titans God

which has the name Atlas who is holding the Universe on his

shoulders; so this vertebra is holding the whole head skull.

Now we will talk about the 2nd cervical vertebra Axis:


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Its atypical because it has an additional feature rather than the 4

that we mentioned:

An additional body; that separated from the Atlas and getattached to the Axis in which we call the odontoid process

or the Dens of Axis which bind with the Atlas anteriorly at the

Atlanto-Axial joint, Dens is a Latin word that mean the tooth,

Atlas is like a ring this Dens come inside it this Dens act like an

axis which allow for the rotation of the Atlas rotation of the

head like when you saying NO, this rotational movement isfacilitated by the Atlanto-Axial joint, so the axis is actually acting

like an axis to the Atlas and thats why they called it Axis.

The Dr. mentioned that from now on, if we want to study any joint in

anatomy, we have to answer the following questions regarding to it:

Type: fibrous, cartilaginous or synovial, if it was synovial, what isthe shape of the joint.

Articulations. Movements. Supporting ligaments; especially if it was synovial, because in

the synovial joints the bones are not in contact with each other

instead there is space, so what connects them. It is the

ligaments that extends from on bone to the other

If there are any additional characteristics; like the presence of adisc like the TM joint TMJ, the Dr. said that there only two


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joints in our body that have a complete circular disc which are

the TMJ and the other is a H.W.

We will now study the Atlanto-occipital and the Atlanto-Axial joints.

Type: synovial because there is a free movement between theskull and the Atlas, condyloid because there are two smooth

rounded condyles that comes from the occipital bone of the

skull, so we call this joint condyloid synovial joint.

Articulations: lateral mass of Atlas and the condyles of the skull. Movement: the movement by which you move your head by

saying YES, so just Flexion and Extension between the Atlas

and the skull (skull and vertebral column), and when you bend

your head we call it lateral flexion .


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Supporting ligaments: there are two ligaments:

1-Posterior Atlanto-Occipital membrane that extend from theposterior arch of Atlas and goes to the foramen magnum fromthe back posterior margin of foramen magnum.

2-Anterior Atlanto-Occipital membrane that extend from the

anterior arch of atlas and goes to the foramen magnum from the front

anterior margin of foramen magnum.


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Movement: rotational movement between the Atlas and theAxis which start within the vertebral column itself (the skull has

nothing to do with it).

Articulations between the Atlas and the Axis: there are threejoints; two lateral Atlanto-Axial joints between lateral masses of

Atlas and inferiorly with the Axis and a median Atlanto-Axial

joint between the anterior arch of Atlas and the Dens of Axis.

Type: The two lateral Atlanto-Axial joints are Plane or SlidingSynovial joints, the other one is a Pivot Synovial joint.


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The articulation of the median Atlanto-Axial joint:

Anterior arch of Atlas. Dens of Axis. Transverse ligament of Atlas: A ligament that is a part of

articulation because without this ligament the Axis will not going

to connect with the Atlas, this ligament is extending in a

transverse direction from one lateral mass of Atlas to another

lateral mass in the opposite side.

The supporting ligaments for that joint; this joint is veryimportant and losing the connection of this joint will lead to a

severe trouble because of the sensitivity of this area, these

ligaments are arranged into three layers from the front to the

back:

1-Apical ligament: That fix the Dens in its place, extend from tip of the

Dens to the anterior margin of foramen magnum.

2-Alar ligaments: That fixes the Dens laterally on the sides, extends

from the side of the Dens to the lateral margins of foramen magnum.

These three ligaments form the first layer of ligaments.


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3-Cruciate ligament: which means crucified (like a plus +), its

composed of 3 parts:

Horizontal transverse part: It is the same of the transverseligament of Atlas which we talked about.

Vertical ones, to additionally fix the Dens opposite to the arch ofAtlas:

1-Superior longitudinal ligament: extend from the transverseligament of Atlas all the way up into the foramen magnum.

2-Inferior longitudinal ligament: extend from the transverseligament of Atlas all the way down to into the body of the

Axis.

This is the second layer of ligaments.

4-tectorial membrane: this means the tent that will cover all of the

ligaments, which is the superior continuation of the posterior

ligament (that we said that it is thin and weak in the 8th

page).

This is the third layer of ligaments.

Despite all of these ligaments it is very common to have dislocation in

this joint.

The strongest one of them is the horizontal part of cruciate ligament,

if you lose it you will lose the whole joint, all of the rest is not that

important so sometimes when you some people that have the ability


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to move their head more than the normal people by 30% you will see

that there is tearing in the Alar ligaments.

Rupture of the transverse ligament of Atlas; complete dislocation, if

you lose this ligament, the Dens will be projecting backward so it will

leave the arch and goes backward, once the Axis goes back, it either

injuring the medulla or the spinal cord:

If it hits the medulla: Direct death. If it hits the spinal cord: Quadriplegia.The usual cause of death Whiplash Injures which is the most

common kind of Auto-Mobile injuries.

Atlanto-axial subluxation:


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Subluxation means partial dislocation or laxity; not complete

dislocation, it will not cause to big problems but there is back pain.

The Dr. said to read the Hyoid bone by yourselves so I include the

slide regarding to it.

Hyoid bone:

U-shaped bone inf. to mandible

anterior upper cervical region

Part of axial Skeleton.

Forms a base for the tongue.

Consist of:1-Body.2-Two grater horns.3-Two lesser horns.


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Muscular Attachments of Hyoid:

Ant. Sup.: Mandible (Geniohyoid, Mylohyoid, Ant.Digastric).

Post. Sup.: Temporal bone (Stylohyoid, Post. Digastric).

Ant. Inf.: Sternum (Sternohyoid, Sternothyroid &Thyrohyoid).

Post. Inf.: Scapula (Omohyoid).

P.S: I included all the notes from the slide in this script.


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Finally I did it, this was one of the hardest things to

write, hope that you will enjoy your reading .

Forgive me for any mistakes as I tried my best with this

lecture.

I want to thank my friend Hamza Al-Ogaily for his

support.

Your colleague: Ibrahim Mahmood Bayram.

When we honestly ask ourselves which person in

our lives means the most to us, we often find that it

is those who, instead of giving advice, solutions, or

cures, have chosen rather to share our pain and

touch our wounds with a warm and tender hand.
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