Joint: articulation between bones; functions by allowing movement and providing stability
Carries weight during posture/gait
Can allow a lot of motion (shoulder) or minimal movement (sternoclavicular joint)
Move movement = less stability
Arthrokinematics: joint surface movement
Type 1 - Synarthrosis (Synarthrodial joint)
Provide stability
Subtype A: Fibrous
Suture: thin layer of fibrous periosteum between the two bones with the ends shaped to allow them to interlock
Ex. Bones of the skull
Ligamentous: joints held together by ligaments/interosseous membranes that allow minimal twisting/stretching; mostly stable
Ex. Distal tibiofibular joint at the ankle held by ligaments
Ex. Ulna & radius are held together by interosseus membranes
Gomphosis: peg-in-socket joint
Ex. Joint between the tooth and wall of the dental socket in the mandible & maxilla
Subtype B: Cartilaginous
Primarily provide stability; allow minimal movement - bending, twisting, & compression
Have either hyaline/fibrocartilage between 2 bones of the joint
Ex. Joints between vertebrae with fibrocartilaginous discs connecting the bones
Type 2 - Diarthrosis (Diarthrodial joint)/Synovial joints
Provide mobility
Has no direct union between bone ends
The capsule surrounding the joint is filled with synovial fluid
Outer layer is strong enough to hold the joint together = stability
Inner layer is lined with a synovial membrane to secrete synovial fluid
Non-axial joint (plane joint): movement tends to be linear with flat joint surfaces that glide on each other
Ex. Intercarpal joint - gliding occurs between two carpal bones
Movement is minimal; involuntarily results from an osteokinematic movement
Uniaxial joint: movement is angular occurring in one plane about one axis with one degree of freedom
Hinge - humeroulnar joint - distal humerus is convex and proximal ulna is concave - permits movement of flexion/extension (sagittal plane/frontal axis)
Pivot - atlantoaxial joint - between the C1 (atlas) and C2 (axis) vertebrae - rotation occurs
Biaxial joint: movement is angular at two planes & two axis = 2 degrees of freedom
Condyloid joints
Ex. Metacarpophalangeal (MCP) joint - distal metacarpal is convex and proximal first phalange is concave
Permits flexion/extension & abduction/adduction
Sellar/Saddle joint
Ex. Bones fit together like a horseback rider in a saddle
Where flex/ext, ab/add, & rotation occur at the carpometacarpal (CMC) joint of the thumb
Triaxial/multi-axial joint: movement within all three planes about all three axes
Joints concave surface is deeper and convex is more spherical
Ball-and-socket
Ex. The hip has a spherical convex surface, the femoral head has a deep concave surface - acetabulum
Allows all three movements
Bones: shape of ends determine the amount/direction of joint movement
Ligaments: bands of fibrous connective tissue, supports and holds a joint together; flexible but not elastic
Flexibility = movement
non-elastic = protection and prevents excessive movement
Capsular ligament: fully encompasses a synovial joint
Synovial membrane: thick, vascular connective tissue that secretes synovial fluid
Synovial fluid: thick, clear fluid consisting of water/dissolved protein
Function: lubricates the articular cartilage to reduce friction, major source of nutrition for articular cartilage; shock absorption
Intraarticular ligament: ligaments that occur within the joint (ex. ACL)
Cartilage: dense, fibrous connective tissue that can withstand pressure & tension
Hyaline cartilage (articular cartilage): covers ends of opposing bones within a synovial joint
Lacks blood/nerve supply; synovial fluid provides nutrition
Cannot repair itself
Fibrocartilage: present in synovial and cartilaginous joints primarily responsible for shock absorption & altering articular joint surfaces
Ex. Labrum: fibrocartilaginous ring in the scapular portion of the shoulder joint
Ex. Intervertebral discs: cartilage between the bodies of vertebrae that absorbs stresses imposed on the vertebrae
Elastic cartilage: designed to help maintain a structure's shape while allowing flexibility
Ex. External ear & larynx (important for speech)
Tendon: connects muscle to bone; cylindrical cords or flat bands
Muscles provide contractile force to cause movement
Tendon sheath: fibrous sleeves lubricated by secreted fluid surrounding a tendon to reduce the friction or pressure when passing between muscles/bones
Ex. Span the tendons in the wrist
Aponeurosis: broad, flat, tendinous sheet of connective tissue that attaches muscle to bone
Thoracolumbar fascia: the connection between the latissimus dorsi muscle attaching to the origin spanning numerous bones via a aponeurosis
Linea alba: an aponeurosis located in the midline of the anterior abdominal wall attaching the internal oblique and transverse abdominus
Bursae: small, synovial fluid-filled, pillow-like sacs located near joints lined with synovial membranes to provide cushioning and reduce friction
Ex. Knee joints
Natural v. acquired bursae
Acquired bursae: in areas that do not normally have excessive friction but develop when abnormal friction occurs
Can disappear or reduce when activity is reduced/stopped
End Feel: sensation a clinician perceives when passively moving a patient's joint to the end of its ROM used to identify the reason for limitation of motion
Overpressure: additional pressure needed at the end of available motion to elicit an end feel
Normal - occurs when joint motion is limited as expected
Soft end feel (soft tissue approximation): occurs when compression of muscle bulk halts movement
Firm end feel: results from tension in structures (ligaments, capsule, muscle) surrounding a joint and is perceived as first resistance to movement with only a slight give on overpressure
Hard end feel (bony end feel): characterized by hard/abrupt limitation of passive joint motion with no give on overpressure
Created by bone contacting bone at the end of motion
Abnormal - presents when pain, muscle guarding, swelling, or abnormal anatomy limits joint movement; types of described by explaining the source of limitation
Boggy end feel: soft, "wet sponge" feel occurring in acute condition with soft tissue swelling
Muscle spasm: reflexive muscle guarding during movement used as a protective response with acute injuries
Empty end feel: occurs when movement produces pain and patient stops movement of the joint beyond the painful point of joint motion
Springy block: a rebound movement, occurring with internal derangement of a joint (ex. Torn cartilage)
Roll, glide, & spin - necessary for joint mobility
All joint movement involves at least one arthrokinematic movement
Roll: movement of one surface rolling on an adjacent surface; a new point on one joint surface contacts a new point on the adjacent surface throughout the movement
Ex. Knee flexion/extension
Glide: (slide) linear movement of one joint surface parallel to the plane of an adjacent joint surface; a single point of joint surface contacts new points on the adjacent joint surface through movement
Spin: rotation of a single point on joint surface on a single point on the adjacent joint surface; the same point on each joint surface remains in contact throughout the movement
Joint surface shapes (concave/convex) determine the arthrokinematic movement during osteokinematic movements
Concave/convex rule: describes the direction of the arthrokinematic movement of glide during osteokinematic movements
Concave joint surface with glide on a fixed convex surface in the same direction as the end of the moving bone that is farthest from the joint at which movement occurs
Convex joint surface will glide in the opposite direction as the end of the moving bone that is farthest from the joint at which movement occurs
Ex. Cupping the right hand while fisting the left hand; moving left forearm up so that the left fist moves downward - representing the convex surface that is moving opposite the forearm's upward movement
Moving the right forearm up would move the cupped right hand upward as well - represents the concave surface moving in the same direction as the moving bone's distal end
Dislocation: complete separation of the articular surfaces of a joint resulting from disruption of supporting structures (joint capsule & ligaments)
Subluxation: partial dislocation of a joint
Osteoarthritis (degenerative arthritis): type of arthritis caused by wear and subsequent breakdown of cartilage; commonly caused by aging & repetitive motion
Sprains: tears of ligaments and capsules
First degree - mild; involving tearing of a few ligament fibers and no loss of function
Second degree - moderate; involves partial tearing with some loss of function
Third degree - severe; full rupture (tearing) of a ligament that no longer functions
Strain: feres to the overstretching of muscle fibers
First degree - mild; involving tearing of few muscle fibers and no loss of fxct
Second degree - moderate; partial tearing of a muscle with some loss of fxct
Third degree - severe; full rupture of muscle that no longer generates force
Inflammation: normal response to injury marked by localized swelling, redness, increased temperature, & pain
Tendonitis: inflammation of a tendon
Synovitis: inflammation of a synovial membrane
Tenosynovitis: inflammation of a tendon sheath caused by repetitive use
Bursitis: inflammation of a bursa
Capsulitis: inflammation of a joint capsule - can lose its extensibility = loss of joint motion
Capsular pattern: characteristic pattern of each joint of lost motion when capsular tightness is present