Download Skeleton Notes

Skeletal System
Osteology:
osteocyte
periosteum
Bone: connective tissue with a solid matrix
each bone is an organ
FUNCTIONS
1. support: rigid framework
2. protection: CNS, thoracic organs, red bone marrow, pelvic organs
3. body movement: levers
4. hemopoiesis:
5. storage of minerals: calcium and phosphorous
6. storage of lipids: yellow bone marrow
Bone is a living, dynamic, adaptable tissue. It works with the muscular
system for attachment, movement and a source of calcium and with the
cardiovascular system as a site for blood cell production.
SHAPE OF BONES
1. long bones
2. short bones: carpals and tarsals. Transfer forces of movement.
3. flat bones: broad surface for muscle attachment or protection of organs
4. irregular bones: ex. Vertebrae
STRUCTURE OF A LONG BONE: fig. 6.5, p. 134
1. Diaphysis:
contains a central cavity: medullary cavity
the medullary cavity contains lipids: “yellow bone marrow”
the medullary cavity is lined on the inside by endosteum ( c.t.)
2. Epiphysis:
proximal and distal epiphysis
contains “spongy” bone: “cancellous” bone
“red bone marrow”
3. Epiphyseal plate/line: for lengthwise growth (fig. 6.11 p. 139)
4. Periosteum: (c.t.)
two layers: outer fibrous, inner cellular
covers and isolates
important in bone growth and repair
route for circulatory and nerve supply
interwoven with tendons and ligaments
continuous with the joint capsule
Bone: osseous C.T.
solid matrix
vascular
metabolically active: Osteon (functional unit)
Two types: classified according to density or porosity
A) Compact bone: dense, forms walls
1) Osteon: functional unit (Fig. 6.7 p. 136) aka. “Haversian system”
Central canal
Lamellae
Lacuna
Canaliculi
Perforating canals
2) Cells: osteogenic
osteoblast—osteogenesis
osteoclast—osteolysis
osteocyte
B. Cancellous: spongy bone
Contains same components, but arranged differently.
Trabeculae: struts. Decreases weight and protects from stress in
different directions.
Surrounds yellow bone marrow.
Is in epiphysis---red bone marrow.
Periosteum covers long bones except at the articulating end of the proximal
and distal epiphysis. This is articular cartilage: “hyalin” cartilage. It acts like
teflon for joints.
Bone growth and remodeling.
Chondrocytes
Ossification
Skeletal system
Two main divisions:
I. AXIAL skeleton: (ch. 6) axis–lengthwise central line or part around
which parts of a body are symmetrically arranged. Bones of the axial
skeleton support and protect the organs of the head , neck and trunk.
A. Skull
B. Auditory ossicles
C. Hyoid bone
D. Vertebral column
E. Rib cage
***Learn terms of table 6.2 p. 133
Lab starts with the vertebral column (p. 153)
Functions: 1. Support & protect spinal cord
vertebral foramen----vert. canal (part of dorsal cavity)
2. Opening for spinal nerves (intervertebral foramen)
3. Support head
4. Attachment of muscles, ribs and organs
5. Help maintain balance and position
6. Permit movement of head and trunk
Regions
1. Cervical
2. Thoracic
3. Lumbar
4. Sacral
and
curves:
kyphosis
lordosis
General structure of a vertebrae:
Body
Vertebral arch: pedicle & lamina
Vertebral foramen
7 processes come off the vertebral arch
(1) spinous process
(2) transverse processes
(2) superior articular processes
(2) inferior articular processes
scoliosis
ARTICULAIONS
Arthron: arthritis, arthroscopic surgery
I. Functional classification of joints: based on degree of movement.
A) Synarthroses
B) Amphiarthroses
C) Diarthroses
II. Structural classification of joints: based on structure of joint.
A) Fibrous
B) Cartilaginous
C) Synovial
Functional class
Structural class
a) fibrous
Synarthroses
b) cartilaginous
“synchondrosis”
Example
suture
gomphosis
epipyseal plate
c) bony fusion
“synostosis”
Amphiarthroses
Diarthroses
a) fibrous
“syndesmosis”
between bones of
antebrachium and
leg (crural)
b) cartilaginous
“symphysis”
fibrocartilage pad
Intervertebral disc
Symphysis pubis
Synovial
joint capsule with
synovial fluid
Structure of a Synovial Joint
1. Joint capsule: fibroelastic tissue, continuous with the periosteum
a) synovial membrane: lines inside of the capsule
secretes synovial fluid
2. Synovial fluid: lubricates
nourishes the chondrocytes
acts as shock absorber
contains WBC
3. Articular cartilage: “hyaline” cartilage
avascular
teflon
4 Menisci (knee) fibrocartilage pad: cushions
guides
(TMJ–has “articular disc”)
5. Ligaments: dense fibrous C.T. connect bone to bone.
can be inside joint capsule as well as outside
6. Bursae: flattened sacs that contain synovial fluid
located where tendon passes over a bone or between muscles
7. Tendon sheath: similar to bursa but surrounds tendons(carpus and tarsus)
8. Tendons: dense fibrous c.t. that connects muscle to bone (periosteum)
Range of motion determined by:
1. Bone structure (olecranon process and fossa)
2. Strength of joint capsule, ligaments and tendons
3. Muscles that span the joint
Structural classification of Synovial Joints
1. Gliding – side to side; nearly flat; back & forth (little rotation)
Ex. Wrist – carpls; Ankle – tarsals
Sternoclavicular jt.; sup – inf art. P.
2. Hinge – Monaxial - movement
One plane: knee, elbow, phalanges
3. Pivot – Rotation: C1/C2 – Prox radius/ulna
4. Condyloid – Convex – Concave – biaxial 
Radius - carples
5. Saddle – Convex – Concave; metacarples (thumb) - carples
6. Ball and Socket - multiaxial
Read: Tibiofemoral joint (knee) p. 215-216
SKULL
Sutures: coronal, sagittal, lambdoidal, squamosal, median palatine
(fontanels: ossify by 24 months)
I. CRANIAL BONES:
A) FRONTAL (1): supraorbital margin, supraorbital foramen, frontal
sinuses
B) PARIETAL (2):
C) TEMPORAL (2):
1) squamous part: zygomatic process, mandibular fossa
2) tympanic part: external acoustic meatus, styloid process
3) mastoid process: stylomastoid foramen
4) pterous part: carotid canal
D) OCCIPITAL (1): foramen magnum, occipital condyles, hypoglossal
canal, external occipital protuberance, superior nuchal line
E) SPHENOID (1): body–sella turica & sphenoid sinus
lesser wing, greater wing, medial & lateral pterygoid process,
optic canal, superior orbital fissure, foramen ovale
foramen rotundum, foramen lacerum, foramen spinosum
F) ETHMOID (1): crista galli, cribriform plate & foramina, superior and
middle nasal concha, perpendicular plate, ethmoid sinus
II. FACIAL bones:
A) MAXILLA (2): dental alveoli, palatine process, infraorbital foramen,
inferior orbital fissure, maxillary sinus, median palatine
suture
B) PALATINE (2): horizontal plates, perpendicular plate, orbital surface
C) ZYGOMATIC (2): temporal process (part of zygomatic arch)
D) LACRIMAL (2): nasolacrimal canal
E) NASA; (2):
F) VOMER (1):
G) MANDIBLE (1): body, ramus, condylar process, coronoid process,
mandibular notch, mandibular foramen, pterygoid
tuberosity, mylohyoid line
III. Other bones
A) Auditory ossicles: malleus, incus, stapes
B) Hyoid: body, greater and lesser cornu
SKULL
A) Cranial bones: enclose and protect the brain
B) Facial bones: do not come in contact with the brain, framework for face,
support teeth, attachment for muscles that move jaw and for
facial expression
Inside the cranium, there are three fossas:
1) anterior cranial fossa: base of frontal bone (roof of orbit) to lesser wing
of sphenoid, area for frontal lobes of cerebral hemisphere
2) middle cranial fossa: lesser wing of sphenoid to petrous part of temporal
bone area for temporal lobes of cerebral hemispheres
3) posterior cranial fossa: petrous part of temporal bone to occipital bone
area for cerebellum, pons, medulla oblongata