A&P Chapter 08

Joints

Anatomy & Physiology

ivyanatomy.com

Chapter 8

The science of joints is called arthrology.

Joints (articulations)

Joints (Articulations):• Functional junctions between bones

• Bind parts of skeletal system together

• Make bone growth possible

• Permit parts of the skeleton to change shape during childbirth

• Enable body to move in response to skeletal muscle contractions

Functional Classification of Joints (based on amount of movement)• Synarthrotic = immovable

• Amphiarthrotic = slightly moveable

• Diarthrotic = fully movable

Structural Classification of Joints (by types of tissue):• Fibrous joint = dense connective tissue

• Cartilaginous joint = bones connected by cartilage

• Synovial joint = contains a synovial membrane

Joint Classification

Syndesmosis:• Bones are connected by a sheet of

dense connective tissue (interosseous membrane) or bundle of dense connective tissue (interosseous ligament)

• Amphiarthrotic• Example: between tibia and fibula

Fibrous JointsFibrous joints are held together with dense connective tissue containing many collagen fibers; found in bones in close contact•There are 3 types of fibrous joints:

• Syndesmosis• Suture• Gomphosis

Fibrous JointsSuture:• Between flat bones of skull• Thin layer of connective

tissue (sutural ligament)

connects bones• Synarthrotic (immovable)

Gomphosis:• Cone-shaped bony process in a

socket in jawbone• Tooth in jawbone by periodontal ligament• Synarthrotic (immovable)

Periodontal ligaments

Cartilaginous Joints

Cartilaginous joints are connected by hyaline cartilage or fibrocartilage

There are 2 types of cartilaginous joints:• Synchondrosis• Symphysis

Synchondrosis:• Bones are joined by a band of hyaline cartilage• epiphyseal plates in children (ossification

converts this to a synostosis)• Between first rib and manubrium• Synarthrotic

synchondrosis joints

Symphysis• A pad of fibrocartilage

between two bones

• pubic symphysis

• intervertebral discs

• Amphiarthrotic movement.

Cartilaginous Joints

Synovial Joints are Freely movable (Diarthrotic)

Synovial Joints include:• Articular cartilage

• Synovial membrane – secretes synovial fluid

• Joint cavity – filled with synovial fluid

• Joint capsule – dense connective tissue that stabilizes and protects joint

Synovial Joints

Synovial Joints (continued):

• Ligaments – bundles of collagenous fibers that reinforce the joint capsule

• Menisci (sing. Meniscus) – pad of fibrocartilage that separates some joints.

• Bursa – sac filled with synovial fluid. • Bursitis = inflammation of bursa

Bursae surrounding the knee joint.

Synovial Joints

Ball-and-socket • rounded head + cup-shaped socket.• Movement in all planes (multi-axial).• Allows for flexion/extension;

abduction/adduction; and rotation• Includes hip joint and shoulder joint.

Condylar joint• Oval condyle + elliptical socket• Movements in most planes (bi-axial)• Allows flexion/extension and

abduction/adduction, but no rotation• Temporomandibular Joint• Wrist Joint• Joints between metacarpals and phalanges

Types of Synovial Joints

Plane (Gliding) Joint• Flattened bones slide across each other• Includes carpals and tarsals• ribs 2-7 articulate with sternum

Hinge joint• Increases/decreases angel

between bones• Includes elbow joint• Joints between phalanges

Types of Synovial Joints

Pivot Joint• Rotation around a central axis (uni-axial)• Joint between radius and ulna• Joint between atlas (C1) and axis (C2).

Types of Synovial Joints

Saddle Joint• 2 concave bones positioned at right angles• Includes metacarpal and carpal of thumb

Movement at a joint occurs when a muscle contracts and its fibers pull its moveable end (insertion) towards its fixed end (origin).

Abduction = movement away from the midline(think of someone being abducted, or taken away)

Adduction = movement towards the midline (think of adding together)

Joint Movements

Flexion = decreases the angle of a joint• Bend elbow

Extension = increases the angle of a joint• Extend elbow

Hyperextension = extension beyond the anatomical position

• bend hand back, bend head back beyond anatomical position

Joint Movements

Rotation = movement around a central axis• Twisting the head from side to side• Lateral Rotation/ Medial Rotation

Circumduction = movement so end follows a circular path

• moving the finger in a circular motion without moving the hand.

Joint Movements

Elevation = raising a part• Shrugging the shoulders

Depression = lowering a part• Drooping the shoulders

Protraction = moving a part forward• thrusting head forward

Retraction = moving a part backward• pulling the head backward

Joint Movements

Supination = turning the hand so the palm faces upward or anteriorly

Pronation = turning the hand so the palm faces downward or posteriorly

Dorsiflexion = movement at the ankles that points toes towards the sky

Plantar flexion = movement at the ankles that points toes towards the ground

Joint Movements

Eversion = turning the foot so the planter surface faces laterally

Inversion = turning the foot so the plantar surface faces medially

Joint Movements

The knee joint is the largest and most complex synovial joint in body.

Two distal condyles of the femur articulate with two proximal condyles of the tibia. This is a condylar joint.

The femur also articulates anteriorly with the patella. This is a plane joint.

Knee Joint

1. Synovial Membrane• Secretes synovial fluid

2. Joint Cavity • Stores synovial fluid

3. Joint Capsule• Relatively thin support• Reinforced by several

ligaments and tendons

General structures of a synovial joint in the knee

Knee Joint

• Patellar tendon - (quadriceps femoris tendon) • The patella is partially enclosed in tendons

fused together from the thigh muscle.

• Patellar ligament – continuation of patellar tendon. Extends from patella to the tibial tuberosity.

Several ligaments and tendons strengthen the knee joint.

Knee Joint

• Tibial (medial) collateral ligament – connects medial condyle of femur with medial condyle of tibia.

• Fibular (lateral) collateral ligament – connects lateral condyle of femur with head of fibula.

• Anterior Cruciate Ligament and

• Posterior Cruciate Ligament – provide additional support to medial surface of tibia and femur

Ligaments continued:

Knee Joint

Two menisci (medial & lateral meniscus) separate the femur and tibia, and align them.

Knee Joint

Three major bursae surround the knee joint.

1. Suprapatellar bursa• Largest bursa in body

2. Prepatellar bursa• Between patella and skin• Housemaid’s knee =

prepatellar bursitis

3. Infrapatellar bursa

Knee Joint

Sprain = overstretching or tearing of connective tissue (tendons, ligaments, or cartilage) associated with a joint.

However, the bones are not disarticulated.

Joint Disorders

Arthritis = inflamed, swollen, and painful joints.

1. Osteoarthritis• Most common arthritis

• Occurs with aging

• Articular cartilage degenerates, causing bone to rub against bone.

• Results in stiff and painful joints

• Fingers may appear gnarled and knee may bulge.

Osteoarthritic fingers often take on a gnarled appearance.

Joint Disorders

2. Rheumatoid Arthritis• Autoimmune disorder (immune

system attacks tissue)

• Synovial membrane thickens & becomes inflamed

• Mass of fibrous connective tissue (Pannus) invades synovial space.

• Fibrous pannus destroys articular cartilage, and the joints may swell and ossify.

A hand affected by untreated rheumatoid arthritis. Note: Knuckles may swell as a result of rheumatoid arthritis.

Other symptoms of Rheumatoid Arthritis:• low-grade fever, fatigue, appetite, stiffness.

Joint Disorders

AttributionAttribution• Flexion/Extension X-rays By Cervical_Xray_Extension.jpg: Stillwaterising Cervical_Xray_Extension_view.jpg: Stillwaterising derivative

work: F. Lamiot [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/d/da/Cervical_XRayFlexionExtension.jpg

• Leg Bones By Anatomist90 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/bf/Slide1dede.JPG

• Sagittal Suture By Sobotta's Atlas and Text-book of Human Anatomy 1909 (File:Sobo 1909 46.png) [Public domain], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/4/45/Sobo_1909_46_-_sagittal_suture.png

• Rib cage Henry Vandyke Carter [Public domain], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/8/88/Gray112.png

• Intervertebral disc By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/6/6f/902_Intervertebral_Disk-02.jpg

• Cartilaginous joints (epiphyseal plate and pubic symphysisi) By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/2/2d/906_Cartiliginous_Joints.jpg

• Synovial Joint Structure By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/8/8b/907_Synovial_Joints.jpg

• Bursae of the knee joint. By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/a/a2/908_Bursa.jpg

• Shoulder Joint Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/e/e3/Blausen_0797_ShoulderJoint.png

• Temporomandibular Joint Henry Vandyke Carter [Public domain], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/a/a5/Gray309.png

• Types of Synovial Joints By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/e/ed/909_Types_of_Synovial_Joints.jpg

• Types of Synovial Joints By Tonye Ogele CNX [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/8/85/Body_Movements_I.jpg

• Body Movements By Tonye Ogele CNX [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/8/85/Body_Movements_I.jpg

• Body Movements II By Tonye Ogele CNX [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/bc/Body_Movements_II.jpg

• Knee Joint Anatomy Anterior View. By Anatomist90 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/4/46/Slide2bib.JPG

• Knee Diagram By Mysid [Public domain], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/0/09/Knee_diagram.svg

• Capsule of Right Knee Posterior View. Henry Vandyke Carter [Public domain], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/d/d8/Gray352.png

• Osteoarthritis fingers By Drahreg01 (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/9/9c/Heberden-Arthrose.JPG

• Hand of Rheumatoid Arthritis By James Heilman, MD (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/7/70/Rheumatoid_Arthritis.JPG