Copyright 2010, John Wiley & Sons, Inc. Articulations BIO 238 Copyright 2010, John Wiley & Sons, Inc.

Joint Classification A joint is where two bones meet* Joints may be classified by structure or by function The structural classification of joints: Fibrous joints (bones held together by dense collagen fibers) Cartilaginous joints (bones held together by cartilage) Synovial joints (bones held together by ligaments)

Copyright 2010, John Wiley & Sons, Inc. Joint Classification The functional classification of joints: Synarthrosis (an immovable joint) Amphiarthrosis (a slightly movable joint) Diarthrosis (a freely movable joint) Copyright 2010, John Wiley & Sons, Inc.

Joints (Fibrous Joints) Lack a synovial cavity The articulating bones are held very closely together by dense irregular connective tissue Fibrous joints permit little or no movement 3 types of fibrous joints: Sutures Syndesmoses Gomphoses Copyright 2010, John Wiley & Sons, Inc.

Joints (Fibrous Joints) Sutures Immovable joint Occur only between the skull bones Syndesmoses Permits slight movement Interosseous membrane Between the tibia and fibula in the leg Gomphoses Joint in which a cone-shaped peg fits into a cup shaped socket Articulations of the teeth with the sockets of the maxillae and mandible

Copyright 2010, John Wiley & Sons, Inc. Syndesmoses Copyright 2010, John Wiley & Sons, Inc.

Joints (Cartilaginous Joints) Lack a synovial cavity Allow little or no movement The joint is tightly connected by cartilage 2 types of cartilaginous joints: Synchondroses Symphyses

Cartilaginous Joints Synchondroses Symphyses The Connecting tissue is hyaline cartilage Found in Epiphyseal (growth) plate in bones Symphyses Slightly movable joint Ends of the articulating bones are covered with hyaline cartilage, but a disc of fibrocartilage connects the bones Pubic Symphysis is between the anterior surfaces of the hip bones Also found in the intervertebral joints between the vertebrae

Copyright 2010, John Wiley & Sons, Inc. Synchondrosis Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Symphysis Copyright 2010, John Wiley & Sons, Inc.

Synovial Joints Components of a synovial joint: Ligaments hold bones together for extra support Synovial cavity a space allowing a joint to be freely movable Articular Capsule A sleeve-like capsule enclosing the synovial cavity The articular capsule is composed of 2 layers: an outer fibrous capsule an inner synovial membrane

Synovial Fluid Secreted by the synovial membrane lining the capsule Functions to reduce friction by: lubricating the joint absorbing shock supplying oxygen and nutrients to the cartilage removing carbon dioxide and metabolic wastes from the cartilage

Copyright 2010, John Wiley & Sons, Inc. Synovial Joints Accessory Ligaments and Articular Discs May be present in some joints for example the knee joint Collateral ligaments of the knee joint (Medial and Lateral) Cruciate ligaments of the knee joint (Anterior and Posterior) Menisci ( C shaped and O shaped) Pads of cartilage lie between the articular surfaces of the bones Allows bones of different shapes to fit together more tightly Copyright 2010, John Wiley & Sons, Inc.

Nerve and Blood Supply Nerve and Blood Supply Nerve endings convey information about pain from the joint to the spinal cord and brain Nerve endings respond to the degree of movement and stretch at a joint Arterial branches from several different arteries merge around a joint before penetrating the articular capsule

Copyright 2010, John Wiley & Sons, Inc. Synovial Joints Bursae and Tendon Sheaths Bursae Sac-like structures containing fluid similar to synovial fluid Located between tendons, ligaments and bones Cushion the movement of these body parts Tendon sheaths Wrap around tendons Reduce friction at joints Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Specific terminology is used to designate the movements that occur at joints Movements are grouped into four main categories: 1) Gliding 2) Angular movements 3) Rotation 4) Special movements Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Gliding Simple movement back-and-forth and from side-to-side There is no significant alteration of the angle between the bones Limited in range Intercarpal joints Angular Movements Increase or a decrease the angle between articulating bones Angular movements include: Flexion Extension Lateral flexion (side bending) Hyperextension Abduction Adduction Circumduction Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Flexion Decreases the angle between articulating bones Bending the trunk forward Extension Increases the angle between articulating bones Flexion and extension are opposite movements Lateral flexion Movement of the trunk sideways to the right or left at the waist Hyperextension Continuation of extension beyond the normal extension Bending the trunk backward Abduction Movement of a bone away from the midline Moving the humerus laterally at the shoulder joint Adduction Movement of a bone toward the midline Movement that returns body parts to normal position from abduction Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Circumduction Movement of a body part in a circle Moving the humerus in a circle at the shoulder joint Rotation A bone revolves around its own longitudinal axis Turning the head from side to side as when you shake your head “no” Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Special Movements Elevation Depression Protraction Retraction Inversion Eversion Dorsiflexion Plantar flexion Supination Pronation Opposition Copyright 2010, John Wiley & Sons, Inc.

Types of Synovial Joints Synovial joints are classified based on type of movement Planar (Plane Joints) Hinge Pivot Condyloid Saddle Ball-and-socket Copyright 2010, John Wiley & Sons, Inc.

Types of Synovial Joints Planar Joints Primarily permit back-and-forth and side-to-side movements Intercarpal joints Pivot Joints Allow for rotation Found in the radioulnar and alanto-axial joints Hinge Joints Produce an opening and closing motion like that of a hinged door Permit only flexion and extension Knee and elbow Condyloid Oval-shaped condyle fits into an ellipsoidal socket Joint between carpals and wrist Copyright 2010, John Wiley & Sons, Inc.

Types of Synovial Joints Saddle Two saddle shaped bones fitting together Found in joint between thumb metacarpal and wrist carpal. Ball and socket Provides the greatest ROM Found in the hip and shoulder joints Copyright 2010, John Wiley & Sons, Inc.

Temporomandibular Joint Copyright 2010, John Wiley & Sons, Inc.

Temporomandibular Joint Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Shoulder Joint Ball-and-socket joint formed by the head of the humerus and the scapula More freedom of movement than any other joint of the body Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Elbow Joint Hinge joint formed by the humerus, the ulna, and the radius Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Hip Joint Ball-and-socket joint formed by the femur and the hip bone Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Knee Joint Largest and most complex joint of the body Modified hinge joint Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Range of Motion (ROM) Refers to the range, measured in degrees of a circle, through which the bones of a joint can be moved Measured in a scale up to 360 degrees Measured using a goniometer Range of motion allows us to measure a persons movements and compare them to an average person’s range to determine if they have an injury or impairment Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Factors that contribute to keeping the articular surfaces in contact and affect range of motion Structure or shape of the articulating bones Strength and tension of the joint ligaments Arrangement and tension of the muscles Contact of soft parts Hormones Disuse Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Aging and Joints May result in decreased production of synovial fluid The articular cartilage becomes thinner Discs and muscle may have decrease in water content Ligaments shorten and lose some of their flexibility Osteoarthritis increases with age Stretching, aerobic exercises and strength training has shown to be helpful in minimizing the effects of aging Exercise helps to maintain the effective functioning of ligaments, tendons, muscles, synovial fluid, and articular cartilage by increasing nutrition to the joint Furthermore weight bearing stimulates the joint to produce more bone which prevents osteoarthritis Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Joint Diseases Osteoarthritis The most common type of arthritis A degenerative disease that results from aging and wear. The articular cartilages gradually disintegrate, which causes pain and restricts movement. Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Joint Diseases Rheumatoid Arthritis A chronic autoimmune condition Often the most painful and crippling type of arthritis The synovial membrane thickens, synovial fluid accumulates causing swelling, and articular cartilages are destroyed. The joint is invaded by fibrous connective tissue that ultimately ossifies, making the joint immovable. Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Joint Diseases Dislocation- the displacement of bones forming a joint. Subluxation- a slight dislocation Sprains result from tearing or excessive stretching of the ligaments and tendons at a joint without a dislocation. Bursitis- the inflammation of a bursa. It may be caused by excessive use or injury Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Joint Diseases Herniated disc is a condition in which the nucleus pulposis of an intervertebral disc protrudes beyond the edge of a vertebra. The protruding disk may place pressure on a spinal nerve and cause considerable pain. Copyright 2010, John Wiley & Sons, Inc.

Arthrocentesis

Treatment for Damaged Joints Arthroplasty Joints may be replaced surgically with artificial joints Most commonly replaced are the hips, knees, and shoulders Hip Replacements Partial hip replacements involve only the femur Total hip replacements involve both the acetabulum and head of the femur Knee Replacements Actually a resurfacing of cartilage and may be partial or total Potential complications of arthroplasty include infection, blood clots, loosening or dislocation of the replacement components, and nerve injury Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc. Hip Joint Replacement Copyright 2010, John Wiley & Sons, Inc.

Healthcare Applications: For therapists range of motion (ROM) will be an important tool to determine a clients limitations and a motivating factor for improvement in musculoskeletal injuries. During the acute stages of many of these conditions, massage is contraindicated. However it can be used in later stages to ease muscle tension, reduce pain, and maintain flexibility.