Skeletal System Flashcards
The bones that form the longitudinal axis of the body.
Axial skeleton
The bones of the limbs and girdles.
Appendicular skeleton
System that includes the joints, cartilages, and ligaments
Skeletal system
A dense and smooth bone, that is homogeneous.
Compact bone
A bone composed of small needle-like pieces of bone and lots of open space.
Spongy bone
Bones that are typically longer than they are wide.
Long bones
A generally cube-shaped bone that is typically mostly sponge bone
Short bones
Thin, flattened bones that are usually curved. Two thin layers of compact bones sandwiching a layer of spongy bone.
Flat bones
Bones that do not fit into any one of the 3 main categories. The vertebrae and hip bones fall into this category.
Irregular bones
This makes up most of the bone’s length and is composed of compact bone. Also called the shaft.
The diaphysis
A fibrous connective tissue membrane that covers and protects the diaphysis.
The periosteum
This secures the periosteum to the underlying bone.
Sharpey’s fibers, or perforating
The ends of the long bones that consist of a thin layer of compact bone enclosing an area filled with spongy bone.
The epiphyses
This covers the external surface. It is glassy hyaline cartilage and provides a slippery surface that decreases friction at joint surfaces.
Articular cartilage
In adult bones, there is a thin line of bony tissue spanning the epiphysis that looks a bit different from the rest of the bone in that area.
Epiphyseal line
Seen in a young, growing bone, these cause the lengthwise growth of a long bone.
Epiphyseal plate
The cavity of the shaft is primarily a storage area for adipose (fat) tissue.
Yellow marrow, or medullary cavity
In adults, this is confined to the cavities of the spongy bone of flat bones and the epiphysis of some long bones.
Red marrow
The bumps, holes, and ridges of the bones.
Bone markings
Mature bone cells
Osteocytes
Tiny cavities within the matrix
Lacunae
The lacunae are arranged in concentric circles called
Lamellae
The lamellae are around these
Central (Haversian) canals
Each complex consisting of a central canal and matrix rings is called
Osteon, or Haversian system
These are tiny canals
Canaliculi
The communication pathway fro the outside of the bone to its interior is completed by
Perforating (Volkmann’s) canals
Large, rounded projection; may be roughened
Tuberosity
Narrow ridge of bone; usually prominent
Crest
Very large, blunt, irregularly shaped process.
Trochanter
Narrow ridge of bone; less prominent than a crest
Line
Small, rounded projection or process
Tubercle
Raised area on or above a condyle
Epicondyle
Sharp, slender, often pointed projection.
Spine
Any bone prominence.
Process
Bony expansion carried on a narrow neck.
Head
Smooth, nearly flat articular surface.
Facet
Rounded articular projection.
Condyle
Armlike bar of bone.
Ramus
Canal-like passageway
Meatus
Cavity within a bone, filled with air and lined with mucous membrane.
Sinus
Shallow, basinlike depression in a bone, often serving as an articular surface.
Fossa
Furrow.
Groove
Narrow, slitlike opening.
Fissure
Round or oval opening through a bone.
Foramen
The process of bone formation.
Ossification
Bone-forming cells.
Osteoblasts
Bone breaks into many fragments.
Comminuted
Bone is crushed.
Compression
Broken bone portion is pressed inward.
Depression
Broken bone ends are forced into each other.
Impacted
Ragged break occurs when excessive twisting forces are applied to a bone.
Spiral
Bone breaks incompletely, much in the way a green twig breaks.
Greenstick
These are giant bone-destroying cells in bones, that break down bone matrix and release calcium ions into the blood.
Osteoclasts
This is essential if bones are to retain normal proportions and strength during long-bone growth as the body increases in size and weight.
Bone remodeling
Breaks in the bone.
Fractures
Blood-filled swelling form when a bone breaks.
Hematoma
A mass of repair tissue.
Fibrocartilage callus
The fibrocartilage callus is gradually replaced by one made of spongy bone when a bone fractures is called a
Bony callus
This encloses and protects the fragile brain tissue.
Cranium
This holds the eyes in an anterior position and allow the facial muscles to show our feelings through smiles and frowns.
Facial bones
This forms the forehead, the bony projections under the eyebrows, and the superior part of each eye’s orbit.
Frontal bone
A canal that leads to the eardrum and the middle ear.
External acoustic meatus
A sharp, needle-like projection that is just inferior to the external auditory meatus.
Styloid process
A thin bridge of bone that joins with the cheekbone anteriorly.
Zygomatic process
A rough projection posterior and inferior to the external acoustic meatus.
Mastoid process
This allows passage of the jugular vein which drains the brain.
Jugular foramen
This transmits cranial nerves VII and VIII.
Internal acoustic meatus
The most posterior bone of the cranium.
Occipital bone
The area where the occipital bone joins the parietal bone anteriorly.
Lambdoid structure
A large opening at the base of the occipital bone.
Foramen magnum
The butterfly-shaped sphenoid bone that spans the width of the skull and forms part of the floor of the cranial cavity.
Sphenoid bone
A small depression in the midline of the sphenoid.
Sella turcica
A large oval opening in line with the posterior end of the sella turcica allows fibers of cranial nerve V to pass the chewing muscles of the lower jaw.
Foramen ovale
Opening which allows the optic nerve to pass to the eye.
Optic canal
A slitlike opening through which the cranial nerves controlling eye movements pass.
Superior orbital fissure
A very irregularly shaped and lies anterior to the sphenoid. It forms the roof of the nasal cavity and part of the medial walls of the orbits.
Ethmoid bone
Projecting from the superior surface of the ethmoid bone is the
Crista galli
On each side of the crista galli are many small holes called
Cribriform plates
These are extensions of the ethmoid bone.
The superior and middle nasal conchae
These fuse to form the upper jaw.
Maxillary bones
The upper teeth are carried by the maxillae in the
Alveolar margin
These extensions of the maxillae form the anterior part of the hard palate of the mouth.
Palatine processes
The maxillae contain these that drain into the nasal passages.
Sinuses
These surround the nasal cavity, lighten the skull bones, and act to amplify the sounds we make as we speak.
Paranasal sinuses
These lie posterior to the palatine processes of the maxillae and form the posterior part of the hard palate.
Palatine bones
Commonly referred to as the cheekbones. They form a good-sized portion of the lateral walls of the orbits, or eye sockets.
Zygomatic bones
Fingernail-sized bones forming part of the medial walls of each orbit. Each of these has a groove that serves as a passageway for tears.
Lacrimal bones
The small rectangular bones forming the bridge of the nose.
Nasal bones
The single bone in the median line of the nasal cavity.
Vomer bone
Thin, curved bones projecting from the lateral walls of the nasal cavity.
Inferior nasal conchae
The lower jaw.
Mandible
This bone does not articulate directly with any other bone. It is suspended in the mid-neck region about 2 cm above the larynx.
Hyoid bone
Fibrous membranes connecting the cranial bones in a fetal skull.
Fontanels
The axial support of the body.
Vertebral column, or spine
Before birth, there are 33 of these. But eventually, 9 of these will fuse together to form the sacrum and the coccyx.
Vertebrae
Single vertebrae are separated by pads of flexible fibrocartilage.
Intervertebral discs
