Skeletal System Basics Flashcards
What are the 2 functional parts of the skeletal system?
The axial skeleton and appendicular skeleton
Axial skeleton
The bones of the cranium, spine (cervical, thoracic, lumbar, sacrum), and trunk (hyoid bone, ribs, sternum)
Appendicular skeleton
Bones of the limbs, shoulder, and pelvis
Cartilage
Semirigid form of connective tissue found where flexibility is required
Articulating joint surfaces
Cartilage that provides a smooth low friction gliding surface in synovial joints
Why is cartilage avascular?
Because blood vessels do not enter cartilage
How does cartilage gain nutrients and oxygen?
Diffusion
Does cartilage differ with age?
The younger the person the more cartilage (more flexibility)
Where does cartilage come from?
Mesenchyme
Endochondral ossification
Process of transforming cartilage into bone
Bone function
To support and protect the body and vital cavities. To give a framework for movement. To store salts. To provide nutrition from q production and continuous supply of new blood cells from within the long bone medullary cavity
Periosteum
Fibrous connective tissue covering surrounding each skeletal bone element like a sleeve except the articular cartilage
Perichondrium
Fibrous connective tissue surrounding cartilage
What do periosteal structures do?
Give nourishment and attachment for tendons and ligaments
Compact bone
Provide strength for weight bearing. Greatest amount is in the midshaft of the long bones. All bones have a superficial thin layer of compact bone around a mass of spongy bone EXCEPT in the medullary cavity
Spongy bone
Lies deep to the compact bone, contains yellow fat, red blood cells, and platelet forming cells that organize within the trabeculae (spicules) of adult bones
Classification of bones
Long bones, short bones, flat bones, irregular bones, sesamoid bones
Long bones
Tubular. Have landmark elevations called ridges, crests, and tubercles (humerus + femur)
Short bones
Cuboidal (carpals + tarsals)
Flat bones
Provide protection (cranium)
Irregular bones
Have various shapes (facial bones)
Sesamoid bones
Develop within tendons that cross ends of long bones. Protect tendons from excessive wear (patella)
Bone markings and formations
Appear wherever ligaments, tendons, and fascia are attached to bone + when arteries lie adjacent or enter bones
What are bone landmarks?
Body, capitulum, condyle, crest, epicondyle, facet, foramen, fossa, groove (sulcus), head, line, malleolus, neck, notch, process, protuberance, shaft, spine, trochlea, trochanter, tubercle, and tuberosity
Body
The principle mass of a bone
Capitulum
Small round articular head
Condyle
Rounded knuckle like articular area (occurring in pairs)
Crest
Ridge of bone
Epicondyle
An eminence superior or adjacent to a condyle
Facet
Smooth flat surface, usually covered with cartilage
Foramen
A passage through a bone
Fossa
Hollow or depressed area
Groove (sulcus)
Elongated depression (furrow)
Head
Large smooth rounded articular end
Line
Linear elevation (sometimes called a ridge)
Malleolus
Rounded process
Neck
Short constricted area of bone distal to a head
Notch
Indentation on edge of bone
Process
An extension or projection having a characteristic shape
Protuberance
A bulge or projection of bone
Shaft
The body or diaphysis of a long bone
Trochlea
Spool like articular process (acts like a pulley)
Trochanter
Large blunt elevation
Tubercle
Small raised eminence
Tuberosity
Large rounded elevation
Where are primary ossification center?
In the shaft or diaphysis
Where are secondary ossification centers?
In the epiphysis proximal + distal long bone ends
Metaphysis
Flared bone part nearest the epiphysis
Synostosis
Bone to bone fusion that replace depleted epiphysial plates
How do bones obtain nutrients?
They are richly supplied with blood vessels
Nutrients arteries
Independent branches outside of the periosteum and pass obliquely through the compact bone of the shaft of a long bone via nutrient foramina
Nutrient foramina
Minute holes in the bone surface that allows blood vessels to penetrate
2 types of joint classification
Synovial and non-synovial
Structural characteristics of synovial joints
Joint capsule, synovial membrane, synovial fluid, articular cartilage (joint end surface), accessory parts (disc pads, menisci), and substructural shapes (hinge, pivot, ball + socket, ellipsis, saddle)
Subclassifications of synovial joints
Plane (planar), hinge (ginglymus), saddle (sellar), condyloid (ellipsoid), ball + socket, and pivot
Plane (planar) joints
Gliding or sliding movements (AC joint)
Hinge (ginglymus) joints
Permit flexion + extension only. Movement in one plane around a single axis that runs transversely. Uniaxial joints (elbow)
Saddle (sellar) joints
Permit adduction, abduction, flexion, extension. Movement around 2 axes at right angles to each other. Biaxial joints that allow movement in the sagital and frontal planes (thumb)
Condyloid (ellipsoid) joint
Permits flexion, extension, abduction, adduction, + circumduction (more restricted than saddle joints). Biaxial joints. (Knuckle joints)
Ball and socket joints
Movement in multiple axes and planes. Flexion, extension, abduction, adduction, medial + lateral rotation, + circumduction. Multiaxial joints (femur head)
Pivot joints
Permit rotation around a central axis. Uniaxial. Rounded process of a bone rotates writhing a sleeve or ring (c1 vertebra)
