Anatomy (skeletal system) Flashcards
Bone terminology
‘os’
‘osteo’
Ossification
process in which cartilage is transformed into bone.
The mineralization or harding of bone
Osteoblasts
A cell that makes bone. It does so by producing/ secreting a matrix that is necessary to harden it. (bone forming cells) cell that adds calcium to bone
Osteocyte
mature bone cells that are located in spaces in the ossified matrix called lacunea
can convert back to osteoblasts if a injury makes that necessary (living tissue composing bone)
Matrix
hard intercellular substance
Bone characteristics
second hardest natural substance in body composed of cells embedded in a matrix osteoblasts osteocytes ossification = hardening of the matrix lacunae canaliculi
Function of bone
support protection leverage storage blood cell formation hematopoiesis
Bone structure
Cancellou-> light and spongy
tiny “spicules” of bone, appear randomly arranged
Compact-> heavy and dense
tiny, tightly compacted cylinders of bones
Most basic function of bone
Support
Leverage
Bone
bone acts as levers for the skeletal muscles to move the body
Storage
Bone
Bones acts as a storage sties for minerals, and particularly calcium
Calcium
involved in many important body functions, including muscle contraction, blood clotting, milk secretion, and skeleton formation and mainteance
Cancellous Bone
spicules of bone with many spaces between them
-bone marrow-
spicules arranged to stand up to forces bone is subjected to
(composed of seemingly random arrangement of spicules of bone separated by spaces fill with bone marrow
Compact Bone
outside layer of all bones and shafts of long bones
composed of haversian systems that run lengthwise with the bone
>concentric layers of ossified bone matrix around central canal
Haversian canal contains:
->blood vessels
->lymph vessels
->nerves
>canaliculi-> tiny channel through the bone
Bone structure
periosteum: membrane covers the outer surfaces of bones
outer layer – fibrous tissue
inner layer – osteoblasts
endosteum: membrane lines hollow interior surfaces
Bone cells
osteoblasts-cells that form bone
osteocytes-osteoblasts surrounded by bone
osteoclasts-remodel and remove bone
Osteoclasts
eats away bone, necessary for remodeling to take place by removing bone from where it is not needed
Blood supply to bone
Volkmann’s canals
channels through bone matrix that contain blood vessels
join at right angles to haversian system
nutrient foramina
->large channels in large (and long) bones
->carry blood in and out of bone marrow
may resemble fracture of bone cortex in x-ray
Bloody supply comes from tiny blood vessels that penetrate in from the periosteum. The blood vessels pass through tiny channels in the bone matrix called the Walkman’s canals.
Bone formation
one/ two mechanisms 1. endochondral bone formation >cartilage template replaced by bone >primary growth center ->diaphysis secondary growth center epiphysis 2. intramembranous bone formation bone develops from fibrous tissue membranes occurs only in certain skull bones
Primary growth centre
Uses the cartilage as a template for the bones that will replaced them.
Secondary growth centre
sell*
Endochondral Bone formation
new bone develops along epiphyseal plates of cartilage located between shaft and ends of bones
allows long bones to lengthen
Diaphysis
back*
Epiphysis
back*
Bone shapes
long
irregular
flat
short
Bone marrow
fills the spaces within bones
types of bone marrow
red bone marrow
yellow bone marrow
red bone marrow
hematopoietic tissue
most common type in younger animals
yellow bone marrow
primarily adipose (fat) connective tissue most common type in adult animals can revert to red bone marrow if there was an accident
Bone features
articular surfaces
processes
holes and depressed areas
articular surfaces
the joint surfaces smooth areas of compact bone where bones come in contact with each other = joints covered by smooth, thin layer of hyaline cartilage called articular cartilage surfaces: condyle head facet
processes
lumps, bumps, and other projections on a bone projections on a bone where tendons attach names depend on location: spinous process of a vertebra trochanter on the femur tubercle on the humerus tuberosity on the ischium spine on the scapula crest on the tibia wing on the atlas
holes and depressed areas
foramen
fossa
foramen
(plural foramina)
hole in a bone
something important passes through hole (foramen in a bone) (blood vessel, nerve)
fossa
depressed or sunken area on surface of bone
usually occupied by muscles or tendons
Axial skeleton components
skull, hyoid bones, the spinal column, the ribs, the sternum
define axial skeleton
located along the central axis of the body
bones of the head and trunk
Skull
37-38 separate bones
most bones united by jagged, immovable, fibrous joints = sutures
only the mandible is connected tot he rest of the skull by a freely movable Synovial joint
(cats have loose mandible bone)
Regions of skull bones
cranium
ear
face
bones of the cranium
surround the brain, they are external or internal 2-frontal bones 2-interparietal bones 1-occipital bone 2-parietal bone 2-temporal bones 1-ethmoid bone (internal) 1-sphenoid bone (internal)
Occipital bone
single bone that forms the caudoventral portion or base of the skull
the Foramen Magnum is the centre of the occipital bone and this is where the spinal cord exists the brain
2 occipital condyles
first cervical vertebra: atlas articulates (forms joint) here
c-1
atlas
c-2
axis
atlantooccipital joint
joint that connects the head with the neck
Interparietal bone
2 small bones located on dorsal midline between occipital and parietal bones
may fuse into one bone in older animals
Parietal bone
2 bones form dorsolateral walls of cranium
large and well developed in dogs, cats, and humans
relatively small in horses and cattle
Temporal bones
2 bones located ventral to parietal bones
important for serval reasons:
-form lateral walls of cranium
-contain middle and inner structures
-form TMJ (temporomandibular joints ) joints with mandible
-only ear structure that is visible from outside is the External Acoustic Meatus
Forntal bones
2 bones form the forehead region of the skull and part of the socket that holds the eye
horn core develops here for horned breeds of cattle
paranasal (frontal) sinus contained within frontal bone
internal bones of the cranium
sphenoid bone
ethmoid bone
sphenoid bone
single bone resembles flying bat and forms bottom of cranium
pituitary fossa houses pituitary gland
of most animals contains a paranasal sinus called the Sphenoid sinus
Ethmoid bone
single bone rostral to sphenoid bone
contains cribiform plate for olfactory nerves to pass through
bone of ear
ossicles 3 bones malleus = hammer incus = anvil stapes = stirrup function to transmit vibrations from tympanic membrane across middle ear cavity to cochlea receptor cells covert vibrations to nerve impulses
bones of the face (External)
>incisive bones (2) (hold your incisor teeth) >nasal bones (2) ->dolichocephalic (long nose) ->brachycephalic >maxillary bones (2) >lacrimal bones (2) >zygomatic bones (2) >mandible (1 or 2)
bones of the face (internal)
Hidden
Palatine bones -> the roof of your mouth (2)
Pterygoid bones-> they protects the pharynx if there wasn’t a bone then the tissue will collapse (2)
Vomer bone ->divides the nostril bones (1)
Turbinates-> fine, thin and paper like. Filtering air-> air is funneled through, provide humidify-> warm it up, put pollutants (4)
-> nasal conchae
Hyoid bone
Hyoid Apparatus single U-shaped bone several portions united by cartilage function: support and aid in swallowing (Not just one bone, but a series of tiny bones)
Spinal Column
Vertebral Column consists of series of individual bones vertebrae (singular vertebra) extends from skull to tip of tail 5 regions shorthand cervical C + # thoracic T + # lumbar L + # sacral S + # Coccygeal Cy + #
Vertebrae
consist of a body, an arch, and processes intervertebral disks separate bodies of adjacent vertebrae (Helps supports and incase You can feel the spinous process) arches line up to form the spinal canal 3 types processes: spinous transverse articular
cervical vertebrae
located in the neck region
nearly all mammals have 7
C1 = atlas ->the occipital bone fits into the wings, the smaller the wing the more turn in your head
C2 = axis ->gives the degree of range
Thoracic vertebrae
located dorsal to the thorax
number can vary among and within species
number same as number of pairs of ribs
(Cat, dog, human have 13)
Lumber vertebrae
located dorsal to the abdominal region number can vary among and within species large and bulky to support weight (Lower back Cat, dog, human-> 7)
Sacral vertebrae
fuse to form single, solid structure = sacrum
number fused varies among species
forms sacroiliac joint
(sits on the pelvis
3 bones-> we consider all three as the sacrum because they are tightly together )
Coccygeal vertebrae
bones of the tail
number varies among and within species
appearance varies even within individual animal
Ribs
flat bones that form lateral walls of thorax
number of pairs equals number of thoracic vertebrae
dorsal heads articulate with thoracic vertebrae
(They are not completely bone but some are cartilage -> which allows us to breath)
bone: dorsal ends of ribs
costal cartilage: ventral ends of the ribs
costochondral junction: area where cartilage meets bony rib
(As it comes to the front before it meets the sternum it is hard cartilage
Most are attached to the sternum, some when they are caudal they start to attach to other ribs in front)
Sternum
the breastbone
composed of sternebrae manubrium xiphoid process
forms floor of the thorax
(Individual bones in the sternum-> Sternebra
Xiphoid is the last one
Mammals have a connection between the floating ribs and the diaphragm)
Sternal ribs
ribs whose cartilages join the sternum
asternal ribs
ribs that join the adjacent costal cartilage
floating ribs
unattached ribs
where the ribs are fully bone
dorsal ends of the ribs
costal cartilage
ventral ends of the ribs
costochondral junction
area where cartilage meets bony rib
Appendicular Skeleton
Thoracic limb
Pelvic limb
Thoracic limb
no bony connection to the axial skeleton Contains: scapula humerus ulna radius carpal bones metacarpal bones phalanges
Scapula
flat, triangular bone
longitudinal ridge = spine of the scapula
forms socket portion of shoulder joint
glenoid cavity: shallow, concave articular surface
(Sits at the back (leonice’s tattoo)
Humerus
> long bone of brachium (upper arm from shoulder to elbow)
proximal end is ball portion of shoulder joint
tubercles: processes where muscles attach
shaft extends to distal end to form elbow joint with radius and ulna
(Major supports of weight
Bottom end where we get our elbow joint)
olecranon fossa (a hollow on the dorsum of the distal end of the humerus, just above the trochlea)
condyles: distal articular surfaces
->trochlea
->capitulum
epicondyles: knobs that are non-articular
(Greater tubercle-> hold the joints
Lateral-> ulna forms the elbow)
Antebrachium
The forearm
Ulna
Radius
Ulna
forms major portion of elbow joint
-> olecranon process
-> trochlear notch
shape parallels that of radius
Radius
main weight-bearing bone of antebrachium (before the main bone)
articulates with humerus and ulna
Carpus
two parallel rows of carpal bones proximal row has names distal row has numbers wrist in humans, knee in horses (Styloid process-> serving as points of attachment for muscles, refers to the slender, pointed process)
Metacarpal Bones
extend distally from distal carpal bones to proximal phalanges
numbered medial to lateral
numbers vary by species: horses (1 + 2 vestigial) cattle (2 fused into 1) dogs and cats (5)
(Metacarpal-> palm)
Metacarpal bones of horses
cannon bone:
one large metacarpal bone
splint bones: two vestigial metacarpal bones metacarpal II metacarpal IV
no remnant of I or V
Thoracic limb bones of cattle
two fused metacarpal bones metacarpal III metacarpal IV four digits 2 weight-bearing 2 dewclaws sesamoid bones 2 proximal 1 distal
Equine thoracic limb bones
1 digit with 3 phalanges >long pastern bone (proximal phalanx) >short pastern bone (middle phalanx) >coffin bone (distal phalanx) 3 sesamoid bones >2 proximal >1 distal = navicular
Canine and Feline thoracic lim bones
digit I (dewclaw): 1 proximal phalanx 1 distal phalanx digits II-V: proximal, middle, and distal phalanx sesamoid bones ungual process surrounds claw on distal phalanx (Plural-> phalanges )
Pelvic Limb
Pelvic limb is connected to axial skeleton at the sacroiliac joint. pelvis ilium ischium pubis femur patella fabellae tibia fibula tarsal bones metatarsal bones phalanges
Pelvis
3 fused bones
>ilium
>ischium
>pubis
pelvic symphysis (the midline cartilaginous joint)
acetabulum (the socket of the hipbone, into which the head of the femur fits)
obturator foramina (large opening created by the ischium and pubis bones of the pelvis through which nerves and blood vessels pass)
Femur
long bone of the thigh
head of femur fits into acetabulum of pelvis
trochanters attached to hip and thigh muscles
distal end forms stifle joint
trochlea: articular groove containing the patella
(Biggest sesamoid bone is the patella)
Sesamoid bones
Patella
Fabellae
Patella
kneecap
large sesamoid bone
formed in distal tendon of quadriceps femoris muscle
protects the tendon
Fabellae
2 small sesamoid bones
located in proximal gastrocnemius muscle tendons of dogs and cats
not present in cattle or horses
Tibia
shinbone main weight-bearing bone of lower leg forms stifle joint with the femur forms hock with the tarsus tibial tuberosity tibial crest (top forms the knee joint)
Fibula
thin, complete bone of lower leg ->parallels the tibia not weight-bearing serves as muscle attachment lateral malleolus: knob-like process (Muscle attachments If you have distal tibia fracture then you will most likely have a proximal fibula fracture)
Metatarsal bones
almost exactly the same as metacarpal bones
major differences:
dogs and cats –
4 metatarsal bones (II-V)
horses:
1 large metatarsal bone (cannon bone) and
2 small metatarsal bones (splint bones)
Tarsus
Hock
2 rows of tarsal bones
proximal row named
distal row numbered medial to lateral
Pelvic limb phalanges
almost exactly the same as the thoracic limb phalanges
exceptions:
dogs and cats – usually only 4 digits (II-V)
(If they have extra digits-> polydactyly)
Visceral skeleton
71
Joints
junctions between bones 3 general classifications fibrous ->immovable cartilaginous ->slightly movable synovial ->freely movable
Fibrous joints
Synarthroses immovable joints firmly united by fibrous tissue examples: sutures of skull equine splint bones
Cartilaginous joints
Amphiarthroses slightly movable joints slight rocking movement examples: intervertebral disks, pubic symphysis, mandibular symphysis
Synovial joints
Diarthroses freely movable characteristics: articular surfaces on bones articular cartilage covering articular surfaces joint cavity = joint space ->synovial membrane ->synovial fluid ligaments for stabilization
Synovial joint movements
flexion extension adduction abduction rotation circumduction
Flexion and Extension
Synovial joint movements
opposite movements
increase or decrease angle between two bones
Abduction and Adduction
Synovial joint movements
opposite movements
moves an extremity away(abd) from or toward(add) the medial
Rotation (Synovial joint movements)
twisting movement of a part on its own axis
Circumduction (Synovial joint movements)
movement of an extremity so that distal end moves in a circle
Types of synovial joints
hinge
gliding
pivot
ball-and-socket
Hinge joints
Ginglymus joints
one joint surface swivels around another
only flexion and extension movements
examples: elbow, atlantoocipital
Gliding joints
Arthrodial joints rocking motion of one bone on another primary motion of flexion and extension ->some abduction and adduction possible example: carpus
Pivot joints
Trochoid joints
one bone rotates on another
rotation movement only
example: alantoaxial joint
Ball-and-socket joints
Spheroidal joints
allow all 6 types of synovial joint movements
examples: shoulder, hip
the general anatomic classification for the skeleton are
axial
appendicular
visceral
the long bones of the forelimbs are the
humerus
radius
ulna
the main weight-bearing bone of the ante brachium of the thoracic is the
radius
the pelvic is formed by these three bones
ischium
ilium
pelvic bones
the joint including the patella is called the
stifle
the joint type that allows for the greatest range of motion is a
ball-and-socket joint
the bending of a joint is called
flexion
the medulla of long bones is an important source of
hematopoiesis
the shaft of a long bone is called the
diaphysis
the shoulder blades are called
scapulae
the diaphragm is a muscle of respiration located in the
thorax
the muscle used for mastication are
masseter muscles
The fibrous band of connective tissue at the centre of the ventral abdominal floor is called the
linea alba
The smooth muscles that attach to the hair on the dorsum and raise the hairs when stimulated in dogs and cats are the
arrector pili muscles
the strong, fibrous, white bands that attach muscle to bones are called
tendons
the strong bands of tissue that hold bones together and support organs are called
ligaments
a particular type of tendon that is flat and ribbonlike is called
aponeurosis
The immovable attachment of a muscle or the point at which it is anchored by a tendon to bone is called its
origin
the nerve that causes a muscle to move is called
motor neuron
the membrane of a muscle cell
sarcolemma
facial muscle for chewing
masseters
forms the chest and adducts the forelimb
pectoral
extends distal forelimb
triceps brachii
skin twitch muscle
cutaneous
hip muscle
gluteals
broadest muscle of the back
latissimus dorsi
abdominal wall muscle
rectus abdominis
flexes the hind limbs
Semimembranosus
Muscular characteristics
excitability
contractibility
extensibility
elasticity
muscle functions
provide motion
maintain posture
generate heat
type of muscle
Skeletal
cardiac
smooth
Skeletal Muscle
controlled by conscious mind
moves bones of the skeleton
voluntary striated muscle
well-defined group of cells surrounded by fibrous connective sheath = epimysium
Skeletal muscle attachements
tendons
attach to bones by fibrous tissue bands
aponeuroses
attach to bones or muscles by broad sheets of fibrous tissue
skeletal muscle attachment sites
origin
more stable site
does not move much when muscle contracts
insertion
site that undergo the most movement when a muscle contacts
Skeletal muscle actions
agonist = prime mover
directly produces a desired movement
antagonist
directly opposes the action of an agonist
synergist
contracts at same time as agonist to assist its action
fixator
stabilizes joints to allow other movements
muscle naming conventions
action ->superficial digital flexor shape ->deltoid location ->biceps brachii direction of fibers ->rectus abdominis number of heads or divisions ->biceps brachii ->triceps brachii ->quadriceps brachii attachment sites ->sternocephalicus
Cutaneous muscle
thin, broad superficial muscles
found in connective tissue just beneath skin
little or no attachment to bones
Head and Neck Skeletal Muscles
control facial expressions enable mastication ->masseter muscle move sensory structures support the head raise the head and neck ->splenius ->trapezius move the head laterally close the jaw extend the head and neck and pull the front leg forward ->brachiocephalicus flex the head and neck ->sternocephalicus
Abdominal skeletal muscles (functions)
support abdominal organs
help flex the back
participate in defecation, urination, parturition, vomiting, and regurgitation
have a role in respiration
Abdominal skeletal muscle
arranged in layers >external abdominal oblique muscle >internal abdominal oblique muscle >rectus abdominis >transversus abdominis left and right parts come together at linea alba
Skeletal muscles of respiration (function)
increase and decrease size of thoracic cavity
inspiratory muscles
diaphragm
external intercostal muscles
expiratory muscles
internal intercostal muscles
abdominal muscles
skeletal muscle cell
muscle fiber very large, quite long and thin multinucleate myofibrils form interior of muscle fiber network of sarcoplasmic reticulum system of T tubules (transverse tubules)
