SKELETON Flashcards
essential part of the body of every vertebrate animal.
skeleton
two types of skeleton:
exoskeleton and endoskeleton
consists of the hardened bony or horny structures that develop in the skin and provides external protection to the animal.
exoskeleton
in nature, and consists almost entirely of bone and cartilage
endoskeleton
Osteocytes trapped in lacunae in the matrix due to the deposition of calcium salts around them
Compact Bone
presents a lesser degree of organization than compact bone. Its outstanding feature is a series of branching, overlapping plates of matrix called trabeculae.
Spongy bone or cancellous bone
overlapping plates of matrix , These plates are oriented so as to produce large, interconnecting cave-like spaces. These spaces function well in storage and as pockets to hold the blood-forming cells (hemopoietic tissue) of the bone marrow. They also function in weight reduction.
trabeculae
composed of all endoskeletal structures located at the center or axis of the body
Axial Endoskeleton
Axial Endoskeleton parts
i. Skull
ii. Visceral skeleton
iii. Vertebral column and ribs (it lacks true ribs)
iv. Sternum
consists of all endoskeletal structures located laterally or in the region of the extremities or appendages.
Appendicular Endoskeleton
Appendicular Endoskeleton parts
i. Girdles
* Pectoral girdle
* Pelvic girdle
ii. Bones of the limbs
* Forelimbs
* Hindlimbs
a pair of flat, triangular-shaped bones on the dorsal surface of the skull just behind the nares
nasal bones
Immediately posterior to the nasal is a median, single irregularly shaped bone
sphenethmoid
two long, slender, flat bones, just behind the sphenethmoid. These may be fused that they appear as a single bone. cover most of the brain; they become wide at their Posterior end,
frontoparietals
where frontoparietals joinj and closes the inner ears
prootics
posterior end of the skull is a large opening through which the spinal cord passes
foramen magnum
Surrounding the posterior part of the brain is a bone called
exoccipital
prominent bone project from the exoccipital
occipital condyles
paired, short, teeth-bearing bones that form the anterior most edge of the upper jaw.
premaxillae
paired curved teeth-bearing bones, forming the margin of the jaw. These are the longest bones of the upper jaw. These are wide in front where the premaxillae articulate.
maxillae
Short bones make up the posterior part of the upper jaw, but unlike the premaxilla and maxilla, these do not bear teeth.
quadratojugals
Extending upward from these bones to the prootics, each shaped in the form of a hammer and serves as a brace between the cranium and the posterior portion of the jaws to support the cartilaginous auditory region.
squamosals
Notice the two large openings, where the eyeballs are located
orbits or eye socket
wing-shaped bones in the roof of the mouth just posterior to the premaxillae.
vomers
The ventral surface of each vomer bears
vomerine teeth
slender, rod-like bones on the lower side of the cranium just posterior to the vomers, They extend laterally from near the medium line to the maxillae.
Palatine
dagger-shaped single bone that forms the floor of the cranium
parasphenoid
three-rayed bone serves as braces; each one is located beneath the squamosal, that articulate with the maxillary, the prootic and the quadratojugal.
pterygoid
endoskeletal structure derived from the gill arches and in the frog
Visceral Skeleton
Visceral Skeleton parts
(a) the upper and lower jaws, (b) hyoid apparatus and (c) the cartilages that support the ventral wall of the larynx or voice box
anterior tip consists of two small bones that unite the two halves of the jaw.
mentomeckelian
thin plate of bone that articulates with the mentomeckelian in front and is joined to the outer surface of the anterior part of the angulosplenial.
dentary
strong bone forming the inner and ventral part of each posterior half of the mandible
angulosplenial
Angulosplenial is expanded into a medially projecting process
coronoid process
lies in the floor of the mouth. It is cartilaginous except for the two bony processes and supports the tongue and the larynx. It is a very important support for the muscles used in respiratory movements of the mouth. It is usually absent in prepared skeletons.
hyoid apparatus
flattened median region of the hyoid apparatus
body of the hyoid
Extending as a pair of lateral expansions on the anterior side of the body of the hyoid apparatus
alary processes
pair of longer, horn-like cartilages arising from the antero-medial border of the alary processes
anterior cornua
A pair of pointed but shorter horn-like cartilages, arises from the postero-lateral border of the body of the hyoid
posterior cornua
Medial to the posterior cornua is a pair of elongated bony processes
thyroid processes
very specialized, due to the shortening of the trunk of the body, consists of ten vertebrae
The Vertebral Column
is specialized for articulation with the skull by means of two large facets or depressions, which receive the occipital condyles of the skull
atlas
strongest on the third and fourth vertebrae where they support the attachments of large and powerful muscles
fused ribs
support weaker muscles and are therefore more slender
Posterior vertebrae
The centra of the first seven vertebrae are ____, which means they are concave in front and convex behind
procoelous
both ends concave, The eighth vertebra
amphicoelous
extending laterally from the centrum
transverse processes
Two pairs of articulating processes called, seen extending forward and backward from the neural arch. join or connect adjacent vertebrae
zygapophyses
directed upward
prezygapophyses
directed downward
postzygapophyses
specialized transverse processes for articulation with the ilia of the pelvic girdle
ninth or sacral vertebra
both ends are flat
acoelous
vertebral column is continued beyond the sacral region by the ____. conspicuous dorsal keel, and also a hollow canal, best seen from the anterior end, into which the spinal cord continues.
urostyle
consists of a series of bones and cartilages which encircle the body and provide support for the forelimbs.
pectoral girdle
dorsally located broad, flattened cartilage
suprascapula
Ventral to the suprascapula, bone corresponding to the human shoulder blade.
scapula
Postero-lateral to the scapula is a cup-shaped depression, serves to receive the head of the upper arm bone
glenoid fossa
ventral side of the girdle, the midventral region is a pair of small bones join the identical halves of the pectoral girdle
epicoracoid
space found lateral to the epicoracoid
fenestra
collar bone in human, which is a slender bone anterior to the fenestra.
clavicle
broader bone is found posterior to the fenestra
coracoid
composed of four bones and cartilages, closely associated with the clavicle and coracoid of the shoulder girdle
sternum or breastbone
Projecting anteriorly from the clavicles is a flat cartilage
episternum
An unpaired bone, shaped like an inverted Y, immediately posterior to the episternum
omosternum
posteriorly from the coracoid bones is an unpaired bone
mesosternum
posteriorly, the sternum ends in a large, flat, bifurcated cartilage
xiphisternum
supports the hindlimbs. It consists of two identical halves
pelvic girdle
anterodorsal bone, is the largest part of the pelvic girdle, possesses an extremely long, anteriorly projecting process, which is parallel to the urostyle and reaches as far as the transverse process of the ninth or sacral vertebra, with which it articulates.
ilium
a large bone on the most posterior end of the pelvic girdle
ischium
small triangular bone immediately ventral to the ilium, and anterior to the ischium
pubis
a small round depression on both sides of the pelvic girdle, receives the head of lower limb bone, femur
acetabulum
The bone of the upper arm, proximal end of its head fits into the glenoid fossa
humerus
long the more proximal half of its shaft, the humerus develops a ventrally projecting _______ for the attachment of muscles
deltoid ridge
flanked on either side by small projections
epicondyles
a represents the fusion of two bones, the radius and ulna of other land vertebrates
radioulna
proximal end of the radioulna is extended into a process, which reaches around the distal end of
the humerus and serves for the attachment of muscles.
olecranon
are the bones of the wrist
carpals
bones of the hand proper consist of four slender
bones of the palm to which the phalanges or smaller bones of the digits or fingers are attached.
metacarpals
bones of the fingers
phalanges
proximal end, or head, of the femur fits into a socket or depression in the pelvic girdle.
Acetabulum
corresponds to the separate tibia and fibula of most land vertebrates.
Tibiofibula
corresponding to the carpals of the wrist
tarsals, or anklebones
have the phalangeal formula of 0.2.2.33
Hands
consist of five long bones of the sole to which the smaller bones of the digits are attached
metatarsals
n addition to the normal five metatarsals (I-V), there is also a small bone. This additional bone may represent an extra digit that was once present, or it may represent a sesamoid bone, a bone formed within the connective tissue at a point of stress.
calcar
an extra segment and an extra lever arm after the tarsals
two are the medial tibiale or astragalus and the lateral fibulare or calcaneus
Has a phalangeal formula of 22343
Feet