[2] Lecture 11-appendicular Skeleton Flashcards
What species no longer possesses clavicles
Holsteans and teleosts
Main pectoral elements in bony fishes [crossopterygians, lung fishes, and chondrosteans]
Cleithrum
Composed of both dermal and endochondral components
Pectoral (shoulder) girdle
Dermal components of the pectoral girdle function:
Support endochondral components and articulate them w/ axial skeleton
Provides surfaces for muscle attachment
Dermal components include:
Cleithrum
Clavicle
Interclavicle
What’re the components carry the limb articulation such as the glenoid cavity
Endochondral
which component of the pectoral girdle Serves as major base attachment for limb muscles
Endochondral components
What’re the 3 endochondral components of the pectoral girdle?
Procracoid
Coracoid
Scapula
Do Sharks have endochondral and dermal components of the pectoral girdle?
No only endochondral components
Main component of the shark pectoral girdle?
Coracoid bar
Characteristics of the shark coracoid bar:
Carries fin attachment
Typically “u” shaped
Scapular processes sit on top of lateral ends of coracoid
What species lost the clavicle ?
Holosteans and teleosts
Fishes w/ clavicles?
Nope
Are the dermal components and the dermal skull components attached in tetrapod?
No dermal components are seperate from the dermal skull components
Where is the cleithrum in modern tetrapods?
There is no cleithrum in any modern forms.
Do tetrapods have interclavicle?
Inclavicle appears in fossil amphibians
Clavicles and interclavicles are present in:
Lizards and sphenodon
Furculum
Clavicles + interclavicle
In birds
Brace wings against sternum
Coracoid
Monotremes have clavicles?
Yes, interclavicles and clavicles
Do all animals have clavicles ?
No clavicles are lost in many animals
What is to note of the lack of connection btw pectoral girdle and skull in fossil and modern amphibians
Amphibians allowed for more freedom of movement of head
Cleithrum and clavicle are long slender rods located along anterior margin of scapula in
primitive tetrapods
What is the fate of original coracoid bar in tetrapods?
Becomes paired
Forms a scapulocoracoid cartilage on each side with a glenoid fossa in the middle
- -scapula is above the fossa
- –coracoprecoracoid region is located below fossa
Anuran pectoral girdle:
Interclavicle is a new diamond shaped, unpaired element that appears 1st in fossil amphibians but is lost in modern amphibians
Cleithrum is rudimentary in modern anurans
Salamander pectoral girdle:
Dermal components are lost in modern salamanders
Much of the endochondral girdle remains unossified
What species amphibian has interclavicle?
None it is lost
Frog pectoral consist of dermal and endochondral or just one ?
Both endochondral and dermal.
Purpose of the coracoid and clavicles in frog
Braces for the forelimbs when the frog lands after jumping
Most reptiles pectoral girdle:
Cleithrum disappears early
Endochondral girdle is similar to that of fossil amphibians
The glenoid fossa is formed by articulation of both the scapula and procoracoid, which meet at an angle at the fossa in which 2 species?
Crocodillians and dinosaurs
Dermal elements have dissappeared into the plastron
Pectoral girdle is triradiate
Turtles
- Anterior ventral prong
- Connected to clavicle plate embedded in plastron
- Posterior ventral prong=porcoracoid.
Triradiate pectoral girdle of turtles
Added a true coracoid to pectoral girdle in amniotes
Pelycosaurs
PEctoal girdle in amniotes
- Development of acromion process
- coracoid process is fully developed in monotremes but is reduced to a coracoid process in other mammals
Therapsids and monotremes
PEctoral girdles in amniotes
- endochondral pectoral girdle similar to dinosaurs
- coracoid serve as wing brace against sternum
- clavicle and interclavicle fuse to form furcula “wishbone”
Birds
Both paired clavicles and interclavicle are present
Primitive mammals- including monotremes
- Interclavicles are lost
- clavicles are reduced or lost in running and bounding forms such as ungulates and carnivores
- bats have elongated clavicles and coracoid process (and elongated forelimbs)
- entire coracoid plate. Along w/ procoracoid, lost in marsupials and placentals.
Other mammals -pectoral girdles in amniotes
Original anterior margin of scapula develops a shelf-like process
Scapular spine
Function of acromian process and scapular spine
Serve as attachment sites for muscles that were originally attached to coracoid plate
Seperates the supraspinous fossa from the infraspinous fossa
Scapular spine
Musculature that was originally attached to coracoid plate has shifted to?
The scapula.
Pectoral change from early amphibian to pelycosaurs
Pelycosaurs develop acromian process
Allows passage of blood vessels- structure on the scapula
Suprascapular notch
Pulls humeral head into glenoid cavity
Snubbing
When was cleithrum no longer found in animals? What animal?
Cleithrum was not seen again after early reptiles
This bony structure in only some tetrapods:
Amphibians
Birds
Mammals
Sternum
What animals was the sternum lost in?
Turtles
Snakes
Snakelike lizards
Sternum of urodeles [amphibians]
Cartilaginous plate
Sternum of anurans [amphibians]
Composed of several elements
Well-developed keel attached to sternum of flying birds
Carina
Function of carina:
Provides a large SA for attachment of flight muscles
Is there a keel [carina] present on non-flying birds?
Keel is reduced or absent in non-flying birds
Carina was present in some pterosaurs this is an example of what?
CONVERGENT evo.
Birds w/ a well-developed carina
Carinates
Birds w/o well-developed carina
Ratites
Pelvic girdle lacks __________________ in all vertebrates
Dermal components
Pelvic girdle consists of 3 paired endochondral bones:
Pubis
Ischium
Ilium
Located ventral and anterior to 2 other parts of pelvic girdle
Pubis
Located ventral and posterior to the other 2 parts of pelvic girdle
Ischium
Located dorsal to the other 2 components of pelvic girdle
Ilium
What do the 3 bones of the pelvic girdle accomplish?
Carrying limb articulation in MOST vertebrates
Since Carrying limb articulation in MOST vertebrates is accomplished w/ pelvic girdle where does it articulate?
Acetabular fossa
What bone articulates w/ sacral vertebra [e] either directly or via sacral ribs
Ilium
What 2 bones of pelvic girdle are primarily for muscle attachment?
Pubis and ischium
Bony fish pelvic girdle
A pair of ventral triangular plates fused along midline
Why is fish pelvic girdle never articulated w/ axial skeleton
They don’t walk
Shark pelvic girdle:
Entirely cartilaginous
Main portion of the shark pelvic girdle
Puboischiadic bar w/ 2 spurs called the iliac processes
Male shark pelvic girdle differs from females how>?
Males have claspers for sperm transfer
Are the cartilages homologous in shark to tetrapod pelvic girdle?
Probably not..
The ventral part of the tetrapod pelvic girdle ossified from 2 centers:
Puboishiadic plate
Function of puboishiadic plate
Provides an area of origin of many of the hindlimb muscles
An opening btw the pubis and ischium which provides a passageway for a nerve supplying the limb muscles
Obturator foramen
What nerve passes through obturator foramen
Obturator nerve
Tetrapod pelvic girdle ilium lies _____ to the other 2 components
Dorsal
Develops above the puboischiadic plate and forms from all 3 elements except in crocodilians
Acetabulum**
Ilia are attached to
Sacral vertebrae
______ and ilium from each side fuse to each other along the midline
Pubis
The bony opening of pelvic girdle is significant factor in vertebrates why?
GI, GU, genital systems
Plays a role in laying large eggs or bear live offspring
2 pelvic bones that represent muscle attachemnet points:
Ischium and pubis
Possess prepubic process:
Urodeles- pubis is cartilaginous
Frog pelvic girdle is:
Ossified
Frog: Single slender element in the middle is the caudal vertebra
Urostyle
Frog: Function of urostyle
Used for jumping- large hind legs w/ large muscles that must attach to skeleton
Two long slender elements on either side of pelvic girdle in frog:
Ilia
Frog pubis:
Fused
How many sacral bones in frog?
Single- one only
Turtles have what prominent feature of pelvic girdle?
Obturator foramen
True dinosaurs are divided based on what feature of body?>
Pelvic girdle
Two different dinosaur groups and their girdle type
Saurischians- triradiate
Ornithischians-tetraradiate
Lizard like hop dinosaur
Saurischians- triradiate
Bird like hop dinosaur
Ornithischians-tetraradiate
Dinosaur pelvic girdle acetabulum
Open
3 prongs of the triradiate pelvic girdle
Pubic bones [fused] and 2 additional ischia
4 prongs of tetraradiate pelvic girdle:
Pubic bones are separate [2] and 2 ischia bones
Ilium extends anteriorly rather than posteriorly/dorsally
Mammals and mammal-like reptile
Prepubic process may extend anteriorly from the pubic bones to support young in what species?
Marsupials
This is large opening and may represent the pubioischiadic fenestra found in the pelvic girdles of other tetrapods such as turtles
Obturator foramen
The passageway for the obturator nerve and artery is found along a groove in the:
Superior pubic ramus
The obturator foramen is mostly covered by what for the purpose of increasing SA for muscle attachment?
Fibrous membrane called obturator membrane
In mammalian pelvic girdle, this structure is closed compared to many reptiles, and opens either laterally or lateroventrally.
As w/ most tetrapods it is formed from all 3 pelvic bones:
Acetabulum
In mammalian pelvic girdle this forms strong joint w/ multiple sacral vertebrae
Ilium
3 major components of tetrapod limb:
Humerus
Ulna
Radius
Single, proximal bone of forelimb
Head articulates w/ glenoid fossa of scapula
Distal end articulates w/ ulna (trochlea) and radius (capitulum)
Humerus
In anatomical position, ulna and radius?
ulna and radius are parallel and in same plane w/ ulna lying medial to radius
Semilunar notch of ulna forms _______ joint w/ trochlea of humerus.
Hinge
Olecranon process of ulna serves as ________ ______ for triceps complex.
Lever arm
concave depression on head (proximal end) rotates on capitulum of humerus.
Narrow neck distal to head spins w/in annular ligament attached to ulna.
Wrist articulation is btw distal radius and proximal bones of carpus.
Radius
During pronation and supination, ulna is ______, while head of radius radius…:
Ulna is fixed; while head of radius spins and distal end of radius rotates over head of ulna
Tetrapod hand typically consists of ______ digits w/ varying numbers of phalanges
5
Phalangeal number may be indicated by listing numbers of phalanges per digit beginning with:
Radial side (thumb)
Primitive and mammal-like reptiles phalangeal number:
2:3:4:5:3
Advanced reptiles, modern mammals and human phalangeal number:
2:3:3:3:3
Whales, extinct marine reptiles phalange also number could reach:
13-14 in a single digit. This was useful for swimming
Major features of hind elements:
Femur
Tibia
Fibula
Possesses a greater trochanter.
Many mammals also have 4th trochanter.
Internal trochanter of reptilian______ is replaced by lesser _____ in mammals.
Femur
This is for the attachement of adductor muscles:
Adductor crest
The adductor crest is sometimes replaced by the _______ ________ in some mammals.
Linea aspera
Possesses an anterior crest which forms the anterior border of the shin
Tibia
What is the name of the anterior crest of the tibia:
Cnemial crest
Many mammals possess a seperate ______ in hind limb that pays a role along w/ tibia in forming the ankle (tibio-tarsal) joint.
Fibula
Some mammals have partial or completely fused ___________
Tibia and fibula
Tetrapods may have evolved from: a
Crossopterygian ancestor
Tetrapod limb can be traced back to:
crossopterygian lobe fin
Forelimbs and hind limbs are almost _________
Identical
Fin bones are arranged by:
Sclerotomes
Segmental muscle slips grow down from the :
Somites
3 components of tetrapod limb:
Stylopod
Zeugopod
Autopod
Proximal single element: humerus or femur-
Articulates w/ girdle
Stylopod
2 parallel elements: radius (fibula) and ulna (tibia)
Zeugopod
Carpals, metacarpals, and phalanges
Autopod (proximal to distal)
Carpals
Basipodium
Metacarpals /tarsals
Metapodium
Phalanges
Acropodium
Evo of tetrapod carpus/tarsus:
Reduction in number of bones <12 bones
Primitive carpus/tarsus consists of how many elements:
12
3 proximal elements in tetrapod limb fore and hind:
Radiale, intermedium, ulnare in carpus
fibulare, intermedium, and tibiale in tarsus
How many centralia in early tetrapod:
4
HOw many How many carpal/tarsal in early tetrapod:
5 distal carpalia/tarsalia
In the forelimb of early tetrapod: the centralia are always:
Reduced
Never more than ____ centralia in primitive reptiles
2; in fact single central is common reptilan and mammalian pattern.
______ distal carpal element is typically lost
Fifth
Phalangeal formula for both primitive and mammal-like reptiles =
2:3:4:5:3
Advanced reptile pahlanegal formula=
2:3:3:3:3
Phalangeal formula is as high as 13-14 in a single digit.
Hyperphalangy
What type of evo is found in tetrapod limbs:
Convergent
3 components of hind limb comprising ankle:
tibiale + intermedium + centrale
Reptiles have what difference in ankle joint than humans:
Intratarsal joint; humans articulate from tibia to talus
Foot movement occurs btw astragalus and the calcaneus
Crocodilians
astragalus and calcaneus are closely attached to the fibula and the tibia, and distal tarsals are joined to the metatarsals in what animals:
In dinaosaurs and birds
Ungulate are hoofed mammals what is the tendency in evo in forelimbs and hindlimbs:
Reduction of the digits
Odd numbered digits in ungulates
Perissodactyls-horse, rhinoceros
Even numbered digits in ungulates
Artiodactyls -camels, pigs, sheep
