Elefant Skull

Elefantenschädel

Namutomi 2005 - 1

Namutomi 2005 - 2

Namutomi 2005 - 3

Namutomi 2005 -4

Buzz

Alf

Addo 1

Addo 2

Addo 3

Addo 4

Skull Map

Elefantenschädel

Tach Lutz,

um Mißverständnisse zu vermeiden:

Der Elefantenschädel enthält auch luftgefüllte Hohlräume, die NICHT Bestandteil der Nasennebenhöhlen (und somit über die Nase belüftet sind)!
Die größeren dieser Hohlräume sind tatsächlich luftgefüllt!
Ein Teil enthält galertige Massen.
Die kleineren dieser Hohlräume sind typische Markräume (die Beinknochen z.B. des afrikanischen Elefanten sind praktisch marklos und solider Kortikaler Knochen.)!

Gruß, Hugo, Montag, 19. März 2007 18:13

Moin Hugo,

grundsätzlich ist mir das schon klar. Nur weiß ich eben nicht genau, welche Höhlen luftig und welche flüssig sind. Bitte sei doch so nett gemäß den folgenden Bildern und Zahlen mir luftgefüllt und markgefüllt zuzuordnen. Das war schön!

Gruß Lutz

Gern:

1 Sinus frontalis
4 (2&;18) Sinus maxillaris
12 Sinus ethmoidalis, sind alle luftgefüllt und im wesentlichen über die Nase (oder das Ohr) belüftet. Mit zunehmendem Alter werden diese kleiner und verknöchern.

Gruß, Hugo, Montag, 19. März 2007 19:08

Hugo, dann wäre die Bow Wave Theory aber falsch!

Lutz:

As per your pm request:

What I did was to colour in the major bones and some of their parts on the surface of the skull, front and side. In the adult many of the bones become fused but in the fetus and juvenile the bones are separated from each other by fibrous junctions called suturae.

The elephant skull has 17 major bones of which one is the mandible or lower jaw.

here are the most important ones based on our subject of penetration:

1 The frontal bone : this houses the massive frontal air sinusses, like humans air cavities that communicate with the nasal passage
1a Zygomatic process of the frontal bone
1b Facies orbitalis or medial wall of the eye socket
1c The external opening of the optic nerve canal where the nerve enters the skull on its way to the brain
1d facies temporalis of the frontal bone

2. Nasal proccess of the Nasal bone, this is where the bridge of the nose or most forward muscles of the turnk attach. This bone also has a sinus system that communicates with the nasal passage through a number of canals

2a The Nasal bone which forms the roof and back of the nasal passage

2b The openings of the nasal canals that join the nasal bone air sinusses with the nasal passage

3.Pariatal bone

4. The incisive bone
4a Alveolar proccesses of the incisive bones, houses the 2nd incicors or tusks
4b The body of the Incisive bone, this is aerated with air sinusses
4c The nasal process of the incisive bone

What is imporant about the incisive bone is that in the older animal the maxilla grow forward and perforates the thin plate of the dish shaped incisive bone ( 5a)

5 The maxilla or upper jaw
5a Palatine process of the maxilla, this grows and erodes the incisive bone
5b Frontal process of the maxilla
5c Zygomatic proccess of the maxilla

6. The zygomatic bone

7. Zygomatic process of the Temporal bone
7a squamos part of the temporal bone
7b external auditory canal

8. Lacrimal bone

9a Occipital bone
9b Occipital condyles that articulate with the Atlas ( Cervical verterbra 1)

10 Pterygoid bone

11 Pterygoid process of the basisphenoid

12 Ethmoid with ethmoid air sinusses
12a Crista galli of the ethmoid, this vertical bone plate extending up between the two cerebral hemispheres
12b Cribiform plate
12c lamina perpendicularis of the ethmoid
12d Ossified nasal septum

13 Vomer

15 Nasal canal in trunk
16 brain cavity
17 Foramen magnum
18 parietal bone it is fused with the embryonic interparietal bone

First of all the paranasal sinusses are not theory, they are an anatomical entity, where do you think sinusitus originates from or infections in the Mastoid air cells.

There are various theories proposed about the function of these in the animal skull, they make the bone very light for size, and secondly they act like a subwoofer to aid in elephant communication.

They protect the brain by acting as a buffer ( air is non compressable) against hard blows, remebber many animals use their heads as battering rams. By having air cavities shocks to the skin covered bone are not transmitted to the brain.

They are excellent heat exchangers, in some animals like the Oryx that live in the deserts at very high ambient temperatures these sinusses act like radiators of a fridge.

The maxillary antra also shield the skull from temperature changes within the teeth, if the animal drinks very cold water the teeth would convey this cold to the interior of the skull causing blood vessels to contract..... the roots of the teeth are shielded from the base of the skull by air filled spaces of the maxillary antra

They are air humidfifiers and also in desert animals a source of water for the animal as water vapour in the air is extracted in the sinusses.

Unfortunately they are also a source of problems just like humans, their linings become inflamed and infected and are sometimes a source point of tumours and cancers.

Prof Van Der Merwe of the Anatomy Department at the Vetinary School at Onderstepoort has written the most complete and descriptive paper on the anatomy of the African elephant skull.

There are a total of 17 paired bones in the Adult African elepahnt skull.

They all contain pneumatized air cells ie respiratory cell lined cavtities that communicate either with the nose direct or via other air cells or via the middle ear to the nose

All the bones of the cranium ium and the face are pneumatized except for a small portion of bone above the foramen magnum.

As the animals age some of these sinusses disappear and may be taken over by bone

The larger cavities are similar to that of our own sinusses as humans.

Lutz:

CSF = cerebrospinal fluid in which the brain is bathed, it readily transmits pressure impulses to the brain.

Posted 09 March 2007 07:35

Lutz:

Sorry but I did not see or pay attention to the last part of your question: Which cavities are marrow filled?

This is an interesting point to ponder as we do not have many studies on African elephant.... we do however have very good studies on humans and as humans and elephant grow to the same age ( well within 20 years or so) one could assume similarity.

In the Human fetus the beginnings of the nasal cavity formation starts at around 6 weeks and the actual aeration or pneumatization of bone around 1 to 2 years.

We now know that initially the diploe bone of the skull and face are marrow filled, first red marrow then gradually replaced by "Yellow marrow" and this is gradually replaced by air, the cavities communicate with the nasal passages or in the case of the the petrous bone and mastoid with the middle ear ( in this case the cavities are not lined with ciliated respiratory epithelium but flat squamous cells.

The maximum volume of aeration is around 30 years in the adult and then it starts decreasing.

Studies into the comparative anatomy of the juvenile elephant shows this, mostly marrow filled bone with small volume air spaces, as the animal grows and gets older these spaces become larger and more numerous and as van der merwe and co-authors show it involves all of the bones of the skull and face..... In humans we even see it extended beyond bones in the skull but also the upper cervical vertebra in some rare instances.

JPK:

Sorry but I am going to call you on this one:

"First, the honeycomb contains liquid in 100% of its area in my experience - just that there is more liquid per unit volume the lower you go."

This is simply not true.

The paranasal sinusses of the mammal skull are not fluid filled, they are AERATED The membrane that lines and covers the lamellae of the sinusses are specialized respiratory epithelium ie a pseudo columnar type of epithelium consisting of cilliated cells interspaced with mucus producing goblet cells.

These spaces communicate with the nasal passages through set openings and the clearing of mucous produced happens in set patterns as shown when a drop of methylene blue is dropped on the membrane in one place and then followed.

The mucous production is at a level and rate that the membrane is only coated and it does not collect in appreciable volumes. whilst we see seepage of mucous after a headshot it does not pour out by the gallon. If it does it would have certain pathological implications.

If clearing of mucous is inhibited we get a condition called a mucoceole, this in turn causes a reaction leading to resorption of bone and ultimately deformity. We see this in humans and mammals.

In terms of our understanding of the formation and function of these sinusses if they were 100% fluid filled you would have 200 odd liter of fluid adding 200 kg of weight to the elephant skull which would obviate the reason why these sinusses are formed in the first place.

By implication it would mean that with every headbut our elephant would suffer a concussion because of Hofda's waterhammer theory and more you would be able to kill the elephant whith a captured bolt humane killer..... which we know you cannot do.

JPK

"First, the honeycomb contains liquid in 100% of its area in my experience - just that there is more liquid per unit volume the lower you go."

What is there to misunderstand about 100 % of the "honecomb" contatining fluid ?

Again you make a statement that this "fluid", which is actually mucous which coates and protects the membrane will collect or locate based on gravity ( lower having more than upper)??????

This is not true nor factual.

The mucous moves or is more correctly moved along the surface of the sinus in a set pathway that is neither based on gravity nor pathways that are arranged to drain lower sinusses via a lowest point arrangement..... these cavities are not simply vessels with spigots at their lowest points.

Vacation of mucous is predetermined by the cilliary action of the membrane. The pathway or route is constant for all of a species, so that each region will vacate mucous in a constant manner and will empty into the nasal passage via set openings.

I have seen no evidence to support the notion that "lower" air sinusses have more goblet cells that "upper" sinusses or that mucous production is sex related with the female of the species producing more mucous per unit volume in the sinus than the male.

In fact I discussed this just the other day with the former Professor of ENT surgery at the University of the Orange Free State confirming the work done by Prof Van der Merwe at Onderstepoort on the anatomy of juvenile and adult African elephant skulls.

This has implication regarding the spread of disease etc. for instance local spread of say infection or malignant tumour would be along the pathway of mucous evacuation.

It also asssumes that the animal is in fact alive because once death sets in the ciliary action stops.

JPK:

Everyone who has ever bagged an ele, chopped open the head to get to the tusks assume that the head is filled with fluid because of the fluid seen at the time of the removal off the tusks. Yes we see fluid and yes it may seem to be a lot but that is certianly not the situation in the living state nor that of youre or my sinusses.

How long after your elephants demise do you get to chop open the skull ? one hour, maybe two or even longer? at what point does cellular function stop after death?

You see where I'm coming from.

In the living animal that fluid is only a thin film coating the linings of the cavities, constantly secreted at quite a volume, in the human around 1000 mlper 24 hours and what is more it is moved along at a certain rate and more against gravity.

The rest of the cavity is air filled hence the medical term of AERATED and this aeration proccess begins at birth just after the animal takes it first breath...... the proccess in the elephant goes on to about 30 years from where certain air spaces now recede to be filled with bone.

The recesssion of the cavities decribed by van der merwe et al in their study.

In the human we produce about a liter of mucous per day and unless you have disease it never accumulates anywhere, just a constant movement of this thin layer of fluid all along the surfaces of the sinus cavities. In the maxillary antra ( those cavities in the upper jaw) the movement of fluid is directly up against gravity.

It takes a human sinus cavity 20 minutes to clear itself fully of a single production cycle.

The fact that there is movement and that there is a constant production is a normal function of the nose and it's passages, what is more if it were not so and our heads were filled with fluid we would be in a huge amount of trouble.

Think a human with sinus headache is bad, just imagine a ele bull Wink

ALF, Posted 04 April 2007 03:47

I saw nothing to dispute Alf's description. Although, I didn't see any fluid when a bull skull was chopped as I did with a cow skull. Whether that is enough fluid to transmit a shock wave to the brain I cannot say but I think the theory of the concussion wave being trahsmitted along the hard bones has more merit.

465H&H Posted 04 April 2007 03:58