Lecture 9: Arthrology M/O Chapter 9 45. Classify joints based on the degree of movement allowed and give examples of each classification. 46. Classify joints based on anatomical structure and give examples of each classification. 47. Identify the structural components of the synovial joint, including accessory structures like bursae, tendon sheaths, and ligaments. 48. Describe the anatomical features, locations and possible movements for each of the six structural types of synovial joints. 49. Describe and demonstrate the generalized movements possible at different synovial joints. Arthrology is the study of JOINTS, or ARTICULATIONS...which are the places where two bones meet. The shape of a joint will tell you EVERYTHING about the movements that take place at that joint. Classifying joints by FUNCTION The functional classification of joints groups them by the amount of movement possible (Note: The more mobile the joint, the less stable it is!): 1. Synarthroses (plural): Immovable, or nearly so. 2. Amphiarthroses: slightly movable 3. Diarthroses: very movable Classifying joints by STRUCTURE You can also classify joints based on their structural (or anatomical) characteristics: 1. Fibrous: Held together by dense regular connective tissue A. Gomphoses: Teeth B. Sutures: Skull C. Syndesmoses: Strands of dense regular CT connect 2 bones 2. Cartilaginous: Held together by any kind of cartilage A. Symphyses: bound by a fibrocartilage pad i. Pubic symphysis ii. Intervertebral disks B. Synchondrosis i. Epiphyseal plates! 53
3. Synovial: Held together by an egg sac capsule. A. All synovial joints are diarthroses B. Bones don t actually touch! C. Structure: i. Two (or more) articulating bones ii. Each bone is capped with articular cartilage (a cap made of hyaline cartilage) iii. Bones are separated by a fluid-filled space called the joint cavity iv. Bones (and joint cavity) are encased by the joint capsule, which has 2 layers a. Inner layer is the synovial membrane, which produces synovial fluid that fills the joint cavity. b. Outer layer is the fibrous layer made of dense connective tissue v. Other associated structures: a. Ligaments connect bones...can be extrinsic (outside the joint capsule) or intrinsic (arising from a thickening of the joint capsule itself...) Intrinsic ligaments can be intracapsular or extracapsular. b. Tendons can help stabilize joints c. Bursae are pillows of synovial membrane that reduce friction between structures in the joint... d. When a bursa surrounds a tendon or group of tendons, it is called a tendon sheath. D. 6 types of synovial joints: i. Uniaxial joints a. Hinge joint (allow motion in only a single axis...most common) b. Pivot joint (uniaxial allows a bone to rotate on the longitudinal axis of another bone...) c. Planar/gliding joint: very limited motion ii. Biaxial joints a. Condylar joint (sort of like a ball-and-socket joint, but allows movement in only two planes...) b. Saddle joint (found in the pollex, between the first metacarpal and trapezium...enables opposition!) iii. Multiaxial joints a. Ball-and-socket (hip joint and glenohumoral) 54
Lab 9: Joints and Movement Reading: M&O Ch. 9 Part 1: Movements Movement Opposite Example Other notes Gliding Flexion Extension Hyperextension Lateral flexion Abduction Adduction Radial deviation Ulnar deviation Medial rotation Lateral rotation Circumduction Pronation Supination Depression Elevation Dorsiflexion Plantarflexion Inversion Eversion Protraction Retraction Opposition Part 2: Articulations 1. Using your text and the articulated skeleton as a guide, find an example of each of the following types of joints. Be sure you are clear which type of connective tissue are involved in each of these joints. Joint type Connective tissue(s) Example(s) Movement Suture Gomphosis Syndesmosis Synchondrosis Symphysis Synovial 55
2. Classify the following synovial joints in terms of specific structure (hinge, pivot, gliding, condyloid, saddle, or ball and socket) and the types of movement (flexion, extension, abduction, adduction, rotation, etc.) permitted at the joint. Joint Structure Types of possible movements Temporomandibular Glenohumoral Elbow Radiocarpal Carpometacarpal of thumb Interphalangeal (of hand) Hip Knee (genual) Tibiotalar (talocrural) 3. Examine the following joints in the vertebral column and describe the types of movement (flexion, extension, lateral bending, rotation) permitted at each joint. Then clearly explain how you KNOW this. Joint atlanto-occipital atlanto-axial intervertebral joint: C3 & C4 Movement intervertebral joint: T2 & T3 intervertebral joint: L2 & L3 Part 3: Specific joints Examine the special preparations of the following joints. Know the individual bones involved and notice when ligaments and/or muscle tendons stabilize the joints. Finally, identify the structures in the list below. 1. Examine the cadaver prep of the shoulder joint and identify the following structures: A. articular capsule B. articular cartilage C. rotator cuff muscles (we ll identify them individually later) D. tendon of long head of biceps E. glenoid cavity (fossa) F. glenoid labrum 2. Examine the cadaver prep of the elbow joint and identify the following structures: A. articular capsule B. anular ligament C. radial collateral ligament D. ulnar collateral ligament 3. Examine the cadaver prep of the knee joint and identify the following structures: A. patella B. patellar ligament C. fibular (lateral) collateral ligament D. tibial (medial) collateral ligament E. anterior cruciate ligament F. posterior cruciate ligament G. medial meniscus H. lateral meniscus 56
External Brain 9: Arthrology 45. Classify joints based on the degree of movement allowed and give examples of each classification. 46. Classify joints based on anatomical structure and give examples of each classification. 47. Identify the structural components of the synovial joint, including accessory structures like bursae, tendon sheaths, and ligaments. 48. Describe the anatomical features, locations and possible movements for each of the six structural types of synovial joints. 49. Describe and demonstrate the generalized movements possible at different synovial joints. Your Task 1. Draw a picture of a typical synovial joint and label the following parts: i. Articular cartilages ii. Joint capsule a. Outer fibrous layer b. Inner synovial membrane iii. Joint cavity iv. Ligaments v. Fibrocartilage pad vi. Extension of CT capsule vii. Bursae viii. Tendons 2. Evaluate a movement. Describe the movement using anatomical terms. 3. Speculate on the muscles that would be needed to enable a movement to take place. where would they attach to the bones? 57