Skeletal, Joints,Tendons, Ligaments, Cartilage Flashcards
Skeletal System
The skeletal system (about 206 bones) provides structure and support to the body and is made up of the axial skeletal
system (80 bones including the skull, spine, and ribs) and the appendicular system (126 bones including all other extensions
of the axial skeletal system).
- Divisions of the skeletal system
► Axial skeleton
Skull
Spine
Ribs
► Appendicular skeleton
60 in upper extremities
60 in lower extremities
2 in pelvic girdle
4 in shoulder girdle
Five main categories of bones
Flat Bones Curved surface and provide protection for internal organs Ribs, sternum, clavicle, and scapula
Short Bones Small, cube shaped Carpals and tarsals, calcaneus
Long Bones Long, cylindrical shaft and provide
structural support Tibia, bula, femur, radius, ulna, and humerus
Sesamoid Bones Small bones in the tendon of a
musculotendinous joint - Patella and exor tendon of the foot and thumb
Irregular Bones Serve a variety of purposes; includes the bones of the spine Bones in the ischium and pubis
- Bone structure
► Bone marrow: the soft, sponge like tissue in the center of most bones containing stem cells of red or white
blood cells or platelets
► Cancellous bone: the meshwork of spongy tissue (trabeculae) of mature adult bone, typically found at the
core of vertebral bones and the ends of the long bones
► Compact bone: a denser material, also known as cortical bone, making up the hard structure of the skeleton
- Bone formation
► Osteogenesis: the process of bone formation or remodeling
► Myositis ossicans: a condition when bone tissue forms within a muscle or other soft tissue as a result of trauma or injury
► Cartilage: firm, exible connective tissue that pads and protects joints and structural components of the body
► Wolff’s law: the explanation for bone adaptations as a result of the loads placed on them
- Joint classication
► Fibrous joints: joints with brous connective tissue joining two bones that allow for very little movement
Sutures or synarthrodial joints: This type of joint is found in the skull. During birth, sutures are exible
to allow a baby to pass through the birth canal, and they become more rigid with age.
Syndesmosis: found between some long bones such as the tibia and bula
Gomphosis joints: attach teeth to the sockets of the maxilla and mandible
► Cartilaginous joints: moderately movable joints made of brocartilage or hyaline cartilage
Primary: epiphyseal (growth) plates
Secondary: intervertebral discs (layers of cartilage between vertebrae)
► Synovial joints: uid-lled joints found between bones that move against one another
The type of joint that allows movement
Example: Knee
TYPE OF SYNOVIAL JOINT + EXAMPLE
Gliding - Tarsals of the foot
Condyloid - Radiocarpal joint
Ball and Socket - Shoulder and hip
Hinge - Elbow, ankle, and knee
Saddle Joint - between the thumb and wrist
Pivot - Radioulnar joint
► Arthrokinematics:
the broad term meaning joint motion that can be used in reference to all joint motions
► Close-packed joint position:
the most stable joint position, when the connective tissue is taut and neighboring
bones have the most contact
► Loose-packed joint position:
the less stable joint position represented by any other joint position other than
close packed
Tendons
Tendons connect muscle to bone and serve as a mechanical bridge to transmit the force created by muscle contraction.
► Receptors in the joints, muscles, and tendons help people know where their bodies are in space (proprioception).
Golgi tendon organs are at the junction of muscle and tendon and respond to mechanical stress such
as pressure or muscle tension.
Muscle spindles are sensory receptors within the belly of a muscle that primarily detect changes in the
length of this muscle (stretch).
– Muscles responsible for ne movements contain more muscle spindles than muscles
responsible for gross movements.
Ligaments
Ligaments are tough bands of connective tissue made of collagen and elastin connecting bone to bone.
- Types
► Extrinsic ligament: This type of ligament is located on the outside of a joint. An example is the lateral
collateral ligament (LCL), which resists abnormal movement away from the midline, termed varus stress.
Varus: an abnormal joint movement away from the midline of the body (i.e., bowlegged)
► Intrinsic ligament: The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are situated
inside the knee joint to resist anterior and posterior (forward and backward) movement of the tibia, respectively.
► Capsular ligament: The medial collateral ligament (MCL) is a capsular ligament, so called because it is
continuous with the joint capsule. It resists valgus stress at the knee by keeping the joint approximated.
Valgus: an abnormal joint movement toward the midline of the body (i.e., knock-kneed) - Other key terms
► Elastin: a highly elastic connective tissue allowing many tissues to retain their shape
► Joint capsule: a thin, strong layer of connective tissue containing synovial uid in freely moving joints
Cartilage
Cartilage resists compressive forces, makes bones more resilient, and offers support and exibility in some areas. There are no nerves or blood vessels in cartilage, making cartilage injury recovery a long, arduous process.
- Types of cartilage
► Hyaline cartilage: a transparent cartilage found on most joint surfaces and in the respiratory tract, which
contains no nerves or blood vessels
► Fibrocartilage: an elastic and tough tissue containing type I and type II collagen
Meniscus: a form of brocartilage present in the knee, wrist, acromioclavicular, sternoclavicular, and
temporomandibular joints
► Elastic cartilage: exible cartilage present in the outer ear, inner ear, and epiglottis
Epiglottis: a piece of elastic cartilage in the throat that opens during breathing and closes during swallowing
- Other key terms
► Perichondrium: the connective tissue enveloping cartilage everywhere except at a joint
► Articular cartilage: a form of hyaline cartilage located on the joint surface of bones
► Nociceptors: pain-sensitive nerve endings
