Joints and Articulations

Home , Amphiarthrosis, Condyloid joint, Joint capsule, Pivot joint

Honors Anatomy & Physiology Ms. Susan Chabot Joints/Articulations • Where two bones interconnect • Structure of joint determines movement. • Designed to meet the strength and flexibility required for movement. Functions • Bind parts of the skeleton. • Allow for bone growth. • Permit changes of skeleton during childbirth. • Allow for movement. • Vary considerably in structure and function. • Classified based on degree of movement. AND/OR • The type of tissue that bonds the bones together. Quick Fact There are 230 joints/articulations in the body. Structural Classification of Joints

• Fibrous Joints: held together by collagen

• Cartilaginous Joints: held together by cartilage

• Synovial Joints: separated by cavity filled with fluid Functional Classification of Joints: What kind of movement do they permit?

• Synarthrosis: immovable • Amphiarthrosis: slightly movable • Diarthrosis: freely movable Synarthrosis: Typically Fibrous Joints • No measurable movement occurs at this joint. • Connect bones that are very close to one another. • A thin layer of connective tissue joins the bones together. • Example: sutures between bones of the skull. Amphiarthrosis: Typically Cartilaginous Joints • Allows limited movement. • Absorbs shock. • Use of hyaline cartilage to connect bone. • Example: intervertebral discs. Diarthrosis: REMINDER! Ligaments join bone Synovial Joints to bone. Tendons join muscle to bone! • Most joints fit into this category. • Permits free movement. • Structurally complex. • Ends of bones are covered with smooth cartilage = allows for gliding and prevents bones from rubbing together. • Surrounds a joint capsule filled with fluid to lubricate joints. Types of Synovial Joints

• Ball-and-socket (C) • Condyloid (E) • Gliding (Wrist) • Hinge (A) • Pivot (D) • Saddle (B) Ball-and-Socket • Bone with a rounded (ball-shaped) end that articulates with a cup-shaped cavity. • WIDE range of motion • Example: Shoulder and Hip Condyloid Joint

• Oval shaped bone extension fits into a shallow cavity. • Can move in different directions but NOT rotate. • Example: between metacarpals (bone of palm) and phalanges (fingers). Gliding Joint

• Articulations on an almost flat plane. • Allow for sliding or twisting motion. • Examples: – Between carpal (wrist) and tarsal (ankle) bones. – Sternum and ribs. – Sacrum and pelvis Hinge Joint

• Convex surface of one bone fits into concave surface of another bone. • Resembles the hinge of a door. • Examples: – Joints of the phalanges – Elbow Pivot Joint

• Cylindrical surface of one bone rotates in the ring formed between another bone and a ligament. • Permits rotation. • Example: – Radius and ulna – Cervical vertebrae (neck) and skull. Saddle Joint

• Bone surfaces have both a concave and convex surface. • Bone fits like a puzzle piece. • Allows for a variety of movement. • Example: bones between metacarpal (hand) and thumb. Modeling Joint Construction Project

Let’s Get Started! Special Considerations • Arthritis: inflammation of one or more joints that results in pain, swelling, stiffness, and limited movement Special Considerations • Arthrocentesis: removal of fluid from the joint capsule to alleviate pressure and swelling. Special Considerations • Arthrodesis: surgical union of a joint; fusing two or more bones together

Surgical Union of Lumbar (lower back) Vertebrae. Meniscus Tears • Meniscus are ligaments found in the knee joint. • They assist in stabilizing the knee and limiting motion that could cause injury. • Most injuries require surgical correction. • Becoming more common in young athletes.