Chapter 4: Skeletal System & Joint Actions Flashcards
AXIAL SKELETON
Forms the central axis of the body, mostly concerned with maintaining the structure of the body
-Consists of 80 bones:
Skull
Spine
Ribs
Sternum
SacrumAPPENDICULAR SKELETON
Supports the body's appendages & is mostly concerned with creating locomotor & manipulative movement
- Consists of 126 bones:
60 in upper extremities
60 in lower extremities
2 in pelvic girdle
4 in shoulder girdleLONG BONES
Hard, dense bones that provide strength, structure, & mobility
- Comprised of shaft & 2 ends
- Longer than they are wide with cylindrical shape
- EX: tibia, fibula, etc.
FLAT BONES
Somewhat flat & thin, but may be curved
- Protect internal organs & provide large surface area for muscles to attach
- EX: bones of the skull
SHORT BONES
Typically cube shaped
- Provide support & stability with little to no movement
- EX: bones of wrists & ankles
SESAMOID BONES
Small, independent bone/bony nodule developed in a tendon where it passes over an angular structure
- Reinforce & protect tendons from stress or wear & tear
- Typically in hands & feet
- EX: patella
IRREGULAR BONES
Irregular, complex shaped bones (don’t fit into other classifications)
- Protect organs
- EX: vertebrae & ilium
FACET JOINTS
Joints between two adjacent vertebrae that guide & restrict movement of vertebral column
SPINOUS PROCESS
Bony protrusion on the posterior surface of a vertebrae where muscles & ligaments attach
TRANSVERSE PROCESS
Bony protrusion on the right & left sides of a vertebra where muscles & ligaments attach
OSSIFICATION
Hardening process of bones during development, replaces cartilage with harder bone
- Continues until full physical maturation (18-25 years old)
EPIPHYSEAL PLATE
Location of bone growth near the end of immature bones, the place where bones grow longer
- Cartilage cells divide & push newly formed cells toward the shaft of the bone
EPIPHYSEAL LINE
Line of cartilage near the end of mature long bones, formed when epiphyseal plate closes
- Each long bone has one at each end
STRESS FRACTURE
Thin bone crack due to an accumulation of microdamage
- Can’t be seen with a normal X-ray, CT Scan must be used
X-RAY
Photographic or digital image of internal composition of bones & other hard tissues
COMPUTED TOMOGRAPHY (CT) SCAN
Sophisticated type of X-ray that creates images of bone, blood vessels, & soft tissues across multiple layers
REMODELING
When bone changes shape by either increasing or decreasing its diameter
- Depends on stress/lack of stress placed upon it
DEPOSITION
Adding new bone with osteoblasts
- EX: when client lifts relatively heavy weights, body responds by laying down extra bone to thicken bone’s diameter
RESORPTION
Removing bone with osteoclasts
- EX: in bedridden or paralyzed individuals, the body decreases bone’s diameter
WOLFF’S LAW
Theory that states that bone will adapt to the loads placed upon it
- Bone adaptation
- Developed by German surgeon, Julius Wolff
OSTEOCLASTS
Cells responsible for bone resorption, responsible for loss of bone when inactive or injured
- Chew up impaired bone tissue
OSTEOBLASTS
Cells responsible for bone deposition
- If stimulus for growth is present, osteoblasts lay down new bone
OSTEOCYTES
Mature bone cells that maintain the bone’s matrix
- Osteoblasts transform into osteocytes
PERIOSTEUM
Outer layer of connective tissue that covers long bone, where osteoblasts are located
- Contain cells responsible for growth, repair, & remodeling, as well as pain-sensitive nerve endings
ENDOSTEUM
Connective tissue that covers the inside of bone & the medullary cavity
MEDULLARY CAVITY
Central cavity of the bone shaft
- Marrow storage
COMPACT BONE
Hard, dense outer layer of bone tissue that is resistant to bending
- Makes up about 80% of one’s skeletal mass
- Cortical Bone
SPONGY BONE
Porous, light inner layer of bone tissue
- Trabecular/Cancellous Bone
TRABECULAE
Functional units of spongy bone
OSTEOPOROSIS
Bone disease characterized by a loss of bone mass & density
- Primarily due to the weakening of spongy bone, but compact bone thins as well
BONY PROTRUSION
Eminence on the surface of bones that increases strength & contact area for muscle attachments
OSTEONS (HAVERSIAN SYSTEMS)
Functional units of compact bone, vertically stacked units, each containing a nerve & one or two blood vessels
- Spongy bone is less dense, so trabeculae contain a richer source of blood vessels
3 TYPES OF CARTILAGE
- Hyaline Cartilage
- Fibrocartilage
- Elastic Cartilage
OSTEOARTHRITIS
Bone-on-bone contact that results in joint pain & stiffness from loss of articular cartilage, common in athletes & older populations
- Cartilage is degraded from overuse or aging
NOCICEPTORS
Pain-sensitive nerve endings located in periosteum & endosteum coverings of bone
- Articular cartilage covers ends of moving bone & blocks the pain signal
HYALINE CARTILAGE
Transparent cartilage found on most joint surfaces & in the respiratory tract
- Contains no nerves or blood vessels
- Deformable but elastic
- Most widespread type of cartilage
- Referred to as articular cartilage when at the ends of bones, at articulation points
ARTICULAR CARTILAGE
Form of Hyaline Cartilage located on the joint surface of bones
- Blocks pain signals sent by nociceptors & reduces compressive stress
FIBROCARTILAGE
Tough tissue in the intervertebral discs & at insertions of tendons & ligaments
- Contains Type I & Type II cartilage
- Also forms lateral & medial meniscus of the knee
MENISCUS
Form of fibrocartilage present in the knee, wrist, acromioclavicular, sternoclavicular, & temporomandibular joints
ELASTIC CARTILAGE
Most pliable form of cartilage, present in outer ear, inner ear, & epiglottis
- Gives shape to external ear & forms auditory tube of the middle ear
EPIGLOTTIS
Flap made of elastic cartilage that opens during breathing & closes during swallowing
LIGAMENT
Connective tissue that connects bone to bone; skeleton, bones & cartilage held together by this connective tissue
- Strength derived from Type I collagen fibers (resist strain)
- Possess some elastin (allows tissues to regain shape after stretching)
FUNCTIONS OF LIGAMENTS
- Attach bone to bone
- Passively stabilize & guide a joint
- Resist excess movement at a joint
- Allow brain to sense position of a joint in space
ELASTIN
Highly elastic protein found in connective tissue that allows it to return to its original shape after being stretched
3 TYPES OF LIGAMENTS
- Extrinsic
- Intrinsic
- Capsular
EXTRINSIC LIGAMENT
Ligament located on the outside of the joint; resists varus stress
- EX: Lateral Collateral Ligament (LCL)
INTRINSIC LIGAMENT
Ligament situated inside the joint; resists anterior & posterior movement
- EX: ACL & PCL
CAPSULAR LIGAMENT
Ligament continuous with joint capsule; resists valgus stress, keep joint approximated
- EX: Medial Collateral Ligament (MCL)
VARUS
Abnormal joint movement AWAY FROM midline of the body
- “bow legs” at the knee joint
JOINT CAPSULE
Thin, strong layer of connective tissue that contains synovial fluid in freely moving joints
- Strength comes from Type I collagen fibers
- Resist excess tension at the joint due to nerve innervation; can trigger reflex contractions of surrounding muscles to protect from joint damage
VALGUS
Abnormal joint movement TOWARD midline of the body
- Can result in “knock knees” at knee joint
CREEP
Harmless, temporary deformation of connective tissue
- EX: bending to touch toes, ligaments within the spinal column stretch & then return to their original shape when upright
LAXITY
Permanent deformation of connective tissue caused by excessive stretching; ligament is stretched beyond its structural & functional ability
- Makes joint less stable, resulting in excessive movement
- Increased susceptibility to joint dislocation & osteoarthritis
TEAR
Partial or complete separation of tissue due to a stretch beyond its structural capacity; blood flow to ligaments is less than to muscle & bone, can take 6wks- 1 year to fully heal
- Partial tear can heal with rest
- Complete tear usually requires surgery
SYNOVIAL MEMBRANE
Thin layer of connective tissue beneath joint capsule that makes lubricating fluid
- Lubricates the joint & reduces friction during movement
3 CLASSIFICATIONS OF JOINTS
- Fibrous Joints
- Synarthrodial
- Syndesmoses
- Gomphosis - Cartilaginous Joints
- Synovial Joints
- Ball & Socket
- Saddle
- Hinge
- Gliding
- Pivot
- Condyloid
FIBROUS JOINTS
Connected by dense connective tissue consisting of mainly collagen; “fixed” or “immovable” joints
- 3 Types:
1. Synarthrodial
2. Syndesmoses
3. Gomphosis
3 TYPES OF FIBROUS JOINTS
- Synarthrodial Joints: found in skull, during birth sutures are flexible to allow passage through birth canal
- Become more rigid as you grow - Syndesmoses Joint: found between long bones
- Only slightly mobile - Gomphosis: attach teeth to sockets of mandible & maxilla
CARTILAGINOUS JOINTS
Connected entirely by cartilage (either Hyaline or fibrocartilage), allow more movement between bones than fibrous joint, but less than synovial joints
- Divided into primary & secondary joints
- Primary: epiphyseal plates
- Secondary: manubriosternal joint, intervertebral discs, & symphysis pubis
SYNOVIAL JOINTS
Most movable joints; bones are separated by synovial cavity made of dense, irregular connective tissue; “diarthrosis” joints
- Join bones with a fibrous joint capsule that’s continuous with the periosteum of joined bones, constitute the outer boundary of a synovial cavity & surround the bone’s articulating surfaces
- Categorized by type of movement they allow
CLASSIFICATIONS OF SYNOVIAL JOINTS
- Ball & Socket (Enarthrodial)
- Saddle (Sellar)
- Hinge (Ginglymus)
- Gliding (Arthrodial)
- Pivot (Trochoidal)
- Condyloid (Ellipsoid)
