(3-1) Chapter 3: Osteology The Skeletal System Flashcards
• The study of bones
Osteology
The skeletal system includes the?
bones, and the cartilage, ligaments, and connective tissues that hold everything together
Functions of Bones:
- Protection of vital organs
- Giving rigidity and form to the body
- Acting as levers
- Storing minerals
- Forming the cellular elements of blood
The hard layer that constitutes the exterior of most bones and forms almost the entire shaft of long bones
Compact (dense or cortical) bone
• Composed of spicules arranged to form a porous network
Cancellous (spongy) bone
The spaces of cancellous (spongy) bone are usually filled with?
marrow
• The space surrounded by the cortex of a long bone
Medullary cavity (marrow cavity)
Marrow that are found in young animals
Red marrow
replaces the red marrow as the animal ages
Yellow marrow
The end closest epiphysis to the body is the?
proximal epiphysis
The end farthest epiphysis from the body is the?
distal epiphysis
The cylindrical shaft of a long bone between the two epiphysis
Diaphysis
Is the flared area adjacent to the epiphysis of a mature bone
Metaphysis
- A layer of hyaline cartilage within the metaphysis of an immature bone that separates the diaphysis from the epiphysis
- This is the only area in which a bone can lengthen
Epiphyseal cartilage or disk (physis)
Thin layer of hyaline cartilage that covers the articular (joint) surface of a bone
Articular cartilage
Fibrous membrane that covers the surface of a bone except where articular cartilage is located
Periosteum
Responsible for increases in the diameter of bones
Osteoblasts (bone producing cells)
Fibrous membrane that lines the marrow cavity and osteonal canals (osteons) of a bone
Endosteum
(bone-destroying cells)
Osteoclasts
form an integral part of the joint and covered with articular cartilage
Articular
exist outside of joints
Non articular
includes the skull, vertebral column, ribs, and sternum
Axial skeleton
includes the bones of the limbs
Appendicular skeleton
- Greater in one dimension than any other
- Found in the limbs, where they provide an attachment site for limb muscles and levers for movement
- They have identifiable structural regions
Long bones
- Found only in the carpus and tarsus
- Cuboid, or approximately equal in all dimensions
Short bones
Short bones has no single marrow cavity but the interior is composed of?
spongy bone filled with marrow spaces
Short bones exterior is formed by a?
thin layer of compact bone
Short bones absorb concussion, and they are found in complex joints such as the ? , where a variety of movements as well as absorption of shock occur.
carpus (the “knee” of the thoracic limb) and tarsus (hock)
Relatively thin and expanded in two dimensions
Flat (squamous) bones
Flat bones is mostly found in the regions of the?
skull and in the ribs
Flat bones consist of two plates of compact bone, the?
lamina externa and lamina interna
Flat bones consist of two plates of compact bone, the lamina externa and lamina interna, separated by a spongy material called?
diploë
Flat (squamous) bones generally serve a?
protective or reinforcing function
- Resembles a sesame seed
- Occur along the course of tendons to reduce friction, increase leverage, or change the direction of pull
Sesamoid bones
The shape of sesamoid bones of most domestic animals have decidedly?
un-seedlike shapes
is the largest sesamoid bone
patella
- Unpaired bones on the median plane
- These bones do not fit well into any other descriptive classification
Irregular bones
Contain air spaces or sinuses that communicate with the atmosphere
Pneumatic bones
bones of the skull are examples of pneumatic bones among mammals
frontal bones and maxillary
• Comprises a relatively small part of the skeleton
• Also composed of cells surrounded by an intercellular matrix
Cartilage
Cartilage is ?, thus cartilage responds poorly to injury and does not heal well
avascular
• this cartilage lines the surface of synovial joints and is characterized by a matrix possessing abundant natural lubricants
• Also forms the cartilaginous portion of the ribs, comprises most of the laryngeal cartilages, and serves as the anlage for long bone development
• The most commonly found form of cartilage in the skeleton
Hyaline cartilage
• Particularly durable and resilient, possessing a matrix comprised of extensive bundles of collagenous fibers
• Is more restricted in its distribution that hyaline cartilage
• Found in most symphyses (pelvic, intervertebral) and in the menisci of the stifle and temporomandibular joints
Fibrocartilage
• this cartilage possesses a matrix containing large amounts of elastic fibers
• The resulting cartilage has a great deal of flexibility, but nonetheless considerable strength
Elastic cartilage
Elastic cartilage forms the skeleton of the
pinna, the external nose and the epiglottis
- this joint are capable of minimal to no movement
- Main goal of synarthrosis is to hold the bones together
Fibrous joints
This immovable joint such as those found among the flat bones of the cranium
Sutures
considerable amount of connective tissue intervenes between the two bones in question (e.g. the tibiofibular joint, the attachment of hyoid apparatus to the skull)
Syndesmoses
the specialized joints that hold the teeth in their alveoli
Gomphoses
• this joint permit only limited motion
• Mainly stretching or compression
Cartilaginous joints
This joint are mainly characteristic of growing bone and are lost as the animal matures
Hyaline cartilage joints
• This joint features of the mature skeleton
• They are found in the pelvic symphysis, mandibular symphysis, and between the sternebrae and vertebral bodies
• These joints occasionally ossify with advanced age
Fibrocartilaginous joints
• Permit only relatively wide range of motion
• The range of motion at a joint may be in a single plane (eg. elbow), or in multiple directions (e.g. hip)
Motions that can take place at joints, depending on the form of the joint, include flexion, extension, hyperextension, abduction, adduction, rotation and circumduction
Synovial joints
the ends of which are covered by hyaline cartilage
Two bones
lies between the two apposing bones
joint cavity
that entirely surrounds the joint cavity, extending both proximal and distal
joint capsule
This fibrous layer is a protective, strengthening structure
outer, fibrous layer
This synovial layer secretes the viscous and slick synovial fluid, which provides lubrication for the joint’s movement
inner, synovial layer
Synovial joints types - can be classified according to the amount of mobility afforded by the joint:
- Ball-and-socket
- Ginglymus (hinge)
a tunnel through one or more bones
Canal
a large articular prominence
Condyle
a deep articular depression
Cotyloid cavity
a prominent border or ridge
Crest
prominence just proximal to a condyle
Epicondyle
a smooth, flat surface
Facet
a narrow, cleft-like opening between adjacent bones
Fissure
an opening through a bone
Foramen
a small hollow
Fossa
a shallow, nonarticular depression
Fovea
a long, narrow furrow accommodating a vessel, nerve or tendon
Groove
a rounded articular process
Head
a ridge less prominent than a crest
Line
a tube-like canal through a bone
Meatus
a depression at the edge of a bone
Notch
any prominent, roughened projection from a bone
Process
a sharp, slender process
Spine
a large, blunt process found only on the femur
Trochanter
a pulley shaped structure
Trochlea
a small, rounded process
Tubercle
a large, usually roughened process
Tuberosity or tuber
- refers to a head shape that is closest to the original, natural form of the head found in ancestors.
- proportion of the head are in concert with each other
mesaticephalic
This regions of mesaticephalic are usually nearly the same length and width
facial and cranial regions
This part of mesaticephalic is wide and usually roughly square-shaped
cranium
The junction of the facial and cranial regions is characterized by a notable elevation from the level of the face to the higher level of the cranium. This point is called the?
stop
• The eyes are moderately widely spaced, and fit well within their orbits
• The upper and lower jaws are of the same length, and the dental arcades meet evenly along their full extent
Mesaticephalic
• Form departs from the mesaticephalic form by being longer and more narrow
• The facial and cranial regions are usually of nearly the same length and width
Dolichocephalic
Dolichocephalic cranium is?
narrow and low
Because the cranial region for Dolichocephalic is not as high as in mesaticephalic breeds, what is less pronounced?
stop is less pronounced
The lower jaw is sometimes notably shorter than the upper jaw of dolichocephalic, a condition referred to as?
brachygnathism
Departs from the generalized mesaticephalic form in that it is shorter and wider
Brachycephalic
Brachycephalic facial region is considerably ? than the cranial region.
shorter
The lower jaw is usually longer than the upper jaw, a condition referred to as?
prognathism
Refers to either end of a long bone
Epiphysis
Where the growth of bone takes place
Epiphyseal cartilage
Classification of bones base on location:
- axial skeleton
- appendicular skeleton
Classification of bones base of shape:
- long bones
- short bones
- flat bones
- sesamoid bones
- pneumatic bones
- irregular bones
Bones on or attached to the midline of the body
Axial skeleton