How many bones are in the adult skeleton?
206 bones
Divided into 2 parts - Axial Skeleton (Skull, Vertebral Column, Rib Cage), Appendicular Skeleton (Bones of arms and legs, bones of shoulder, pelvis)
5 functions of the Skeletal System
Support - skeleton enables bodies to stand up
Protection - skull protects the brain: vertebrae protect the spinal cord; rib cage protects the heart and lungs
Movement - Skeletal muscles are attached to bones when muscles contract, the bones produce movement
Storage - bones store and release minerals (calcium & phosphorus) and fat
Blood Cell Formation - Hematopoesis - to make blood
What does Hematopoiesis mean
to make blood
How are bones classified according to shape
Long Bones, Short Bones, Flat bones, Irregular Bones, Sesamoid Bones
Long Bones
typically longer than wide
have shaft with heads at both ends
mostly compact bone
help support body weight and facilitate movement
examples: Humerus, raidus, ulna, femur, tibia, fibula, clavicle, metacarpals, metatarsals, phalanges
Short Bones
Generally cube shape
Contain mostly spongy bone
provide stability and some movement
Examples: carpals and tarsals
Flat Bone
thin, flattened, curved
provide protection & large areas for attachment of muscle
thin layers of compact bone around a layer of spongy bone
Examples: occipital, frontal, & parietal; scapula; the ribs, sternum, illium
Irregular Bone
Irregular Shape
Don’t fit into other bone classification categories
Examples: Vertebrae, sacrum, sphenoid & ethrnoid bones
Sesamoid bone
tiny bone
embedded in a tendon or muscle - aid in movement
provides a smooth surface for tendons to move on
Examples: Patella (knee cap) , few bones in hands and feet - bone inside a tendon where a tendon covers a joint. special type of short bone.
Osteocyte
mature bone cells
Osteoblast
bone-forming cells for bone growth
Osteclasts
Bone destroying cells that break done bone matrix for remodeling and release of calcium
Label parts of the long bone
Quizlet found on classroom
Ossification
Bone growth
Epiphyseal Plates (growth plates)
Bones are remodeled and lengthened until growth stops
Bones change shape, grow in width
Lengthening stops and the epiphyseal plate changes into epiphyseal line
Bone remodeling
After longitudinal growth stops, bones continue to grow thicker and wider and continuously reshape throughout your life
osteoblasts and osteoclasts work together
Open Fracture (compound)
fractures where the bone pierces the skin
Closed Fracture (Simple)
fracture where the bone stays under the skin and doesn’t break it
Complete fracture
fracture where pieces of bone completely separate
Incomplete fracture
fracture where the pieces of the bone do not separate, involve partially separated fragments
Comminuted fracture
fracture that invovles many fragments
Spiral Fracture
bone fracture caused by a twisting force, also called torsion fracture
Greenstick fracture
fracture in which only one side of the bone is broken, bone usually has a bend to it and fracture is located at the outside of the bend, common in young children
Avulsion Fracture
occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone
Harline Fracture (Stress fracture, transverse, oblique)
incomplete fracture which the crack is only in the outer bone later, also called a fissure fracture and linear fracture
Transverse Fracture
fracture straight across the bone, usually the result of sharp, direct blows; the break occurs at a right angle to the bone’s long axis
Oblique fracture
fracture diagonal to bone’s long axis
4 steps to how a bone heals after a fracture
Hematoma 6-8 hrs - blood filled swelling is formed
3 weeks - break is immobilized by fibrocartilage callus
3-4 months - fibrocartilage callus is replaced by bony callus
bony callus is remodeled to form a permanent patch
Synarthortic Joint
No movement (immobile)
provides a strong connection between the adjacent bones
protects internal organs
fibrous joint
Fibrous connective tissue grows between articulating bones
Example: sutures of the skull
Amphiarthrotic Joint
Slight movement (Limited Mobility)
cartilage connects articulating bones
Strongly anchor bones together, but allows for movement
made of fibrocartilage
Example: pubic symphsis
Cartilaginous joint
Diarthortic Joint (Synovial Joint)
surrounded by joint capsule lined with synovial membrane and filled with synovial fluid
supporting ligaments join bones and stabilize joint
some have extra cartilage inside the capsule (meniscus or articular disc)
Bursae
small sacs of synovial fluid between joint & tendons which allow tendons to slide as joints move.
Synovial Joint
See Slides
Ball and Socket Joints
Most mobile joints in the body; various directions
B & S joints are more susceptible to displacement, tearing of ligaments, tendons, or cartilage
Form when ball-shaped end of bone fits into cup-shaped socket of another
Most easily injured
Examples:Â hip & shoulders
Condyloid Joints
Allow for up-and-down and side-to-side movement
Form when oval-shaped end of bone fits into oval socket
Examples: knuckles between metacarpals & proximal phalanges. (Fingers move up & down and can spread out)
Saddle Joints
Only 1 set in the body!
Between the metacarpal bone of the thumb & a carpal bone of the wrist.
Allow for great mobility
Hinge Joints
Allow movement in one direction
Only bending and straightening
Examples:Â Elbows, knees
Plane (or Gliding) Joints
Articulating surfaces are flat & about same size.
Motion is usually small & tightly constrained by ligaments (least mobile of all joints)
Between the carpal & tarsal bones (wrist & ankle), and between vertebrae
Pivot Joints
Rounded portion of bone is nestled into another bone and held in place with a ligament.
Only allows for rotation (or twisting)
Examples:Â C1 & C2 vertebrae (shaking head to say no), the proximal end of the radius & ulna (elbow) which allows you to flip your hand over
Flexion
Bending of the joint that decreases the angle between the bones.
Plantar Flexion
pointing the toe (decreasing angle between calcaneus & tibia)
Dorsiflexion
bending the foot upward toward leg or “flexing the foot” (decreasing angle between metatarsals & tibia)
Extension
Straightening so the angle between joints increases
Hyperextension
overextending the joint beyond its normally straightened position
Adduction
Movement TOWARD the midline of the body.
Abduction
Movement AWAY from the midline of the body
Eversion
Turning the sole of the foot outward.
Inversion
Turning the sole of the foot inward so it faces the opposite foot.
Supination
Turning he hand so the palm faces upward.
Pronation
Turning the hand so the palm faces downward
Circumduction
Movement in a circular rotation
ACL
prevents forward movement of tibia from under the femur
PCL
prevents tibia from moving too far backward under the femur
MCL
joins medial aspects of femur & tibia; resists forces from the lateral side of knee
LCL
connects lateral side of femur & fibulia; holds lateral side of knee together
Menisci
crescent-shaped pads of cartilage between femur & tibia that act as shock absorbers
Which meniscus gets injured more?
Medial meniscus is more susceptible
Osteoarthritis
Degenerative Arthritis”
Results from degeneration of articular cartilage; most common form
Rheumatoid Arthritis
Rheumatism”
Results from inflammation of the synovial membrane; most debilitating & chronic type
Sprains
Joint injury caused by twisting
Causes pain, loss of mobility, swelling & black-blue discoloration of injured area
Ligaments may be torn, but no bone or joint damage has occured
Strains
Injury to the muscle or tendon at a joint
Caused by overuse or overstretching
Less serious than a sprain