Chapter 9-- Joints

Famous Quotes I figured my body always would be able to repair itself. I think all of us believe that – until you begin to age and get hit with deteriorating joints. Lee Majors It had not occurred to me that marriage requires the same effort as a career. And unlike a career, marriage requires a joint effort. Jessica Savitch (1947-1983)

Ch. 9 (Joints) Study Guide Critically read Chapter 9 pp. 278-297 before 9.3 (Anatomy of selected diarthroses). Study all figures in the PowerPoint slides as well. Comprehend Terminology (those in bold in the textbook) within the reading scope above Study-- Figure questions, Think About It questions, and Before You Go On (section-ending) questions (within the reading scope above) Do end-of-chapter questions— Testing Your Recall— 1-4, 6-7, 9, 11-16, 18 True or False– 2, 4, 5, 9, 10 Review/study review sheet document (4 pages) posted on Blackboard 3 3

I. Overview of the joints

Figure 9.1– a gymnast and joint flexibility

§ Why Knuckles Crack and Joints Creak Some peoples' bodies play a percussive symphony of cracking and creaking, thanks to the large orchestra of noise-making human joints. What's behind it all?

§ Joints and their names What are joints? Arthrology = study of the joints Kinesiology = study of musculoskeletal movement (motion of human body) How joints are named? From the names of the bones involved Ex. The atlantoccipital joint Ex. The humeroscapular joint

II. Functional classification of joints

Are all joints able to move? Immovable joints– where? Why? Less movable– ex. vertebral column; why? Moveable—shoulder, elbow, knee Functional classification (freedom of movement) synarthrosis (little/no movement) (“Syn”--together) amphiarthrosis (slightly movable) diarthrosis (freely movable) (‘Dia”– through)

III. Structural classification of joints

§ Structural classification How adjacent bones are joined? Bony joints (synostosis; synarthrosis)– two bones fused Fibrous joints (synarthrosis)—held together by collagen fibers; lack a synovial cavity Cartilaginous joints (amphiarthrosis)– held together by cartilage; lack a synovial cavity Synovial joints (diarthrosis)– having synovial (joint/articular) cavity (Fig. 9.5 next slide)

Fig. 9.5 Synovial Joint Joint in which two bones are separated by a space called a synovial (joint) cavity Most are freely movable

§ 1. Bony Joints (Synostosis) Gap between “two bones ossify”– become a single bone TWO frontal/mandibular bones in infants Can occur in either fibrous joints or cartilaginous as well; Examples: Aging: cranial sutures (fibrous joints) destroyed (ex. Parietal bones fuse) in elderly Aging: attachment of first rib to the sternum (cartilaginous joint) becomes a synostosis with age

§ 2. Fibrous Joints (Synarthrosis-Amphiarthrosis) Collagen fibers span the space between bones Three kinds of fibrous joints A. Sutures— the fibers are short and allow for little movement B. Gomphoses— the fibers are also _____ and allow for little movement; between teeth and the jaw C. Syndesmoses—longer fibers and more movable Figure 9.2

Fig. 9.2 Suture Syndesmosis Gomphosis Fibrous Connective Tissue R. Tibia B A Suture Syndesmosis Gomphosis

Fibrous Joint – A. Sutures Immovable fibrous joints Bind bones together; only in skull 3 types— (Fig. 9.3 next slide) Serrate sutures - interlocking lines coronal, sagittal and lambdoid sutures Lap sutures - overlapping beveled edges Between temporal and parietal bones; Name the suture? Plane sutures - straight, nonoverlapping edges palatine processes of the maxillae Suture

Three types of suture-- Serrate suture Lap suture Plane suture Bone Wood Dovetail joint Miter joint Butt joint

Fibrous Joint – B. Gomphoses Attachment of a tooth to its socket Held in place by fibrous periodontal ligament Consisting of collagen fibers attach teeth to jawbones (which bones?) Little movement (Synarthrosis) while chewing Gomphoses

Fibrous Joint – C. Syndesmosis Two bones bound by broad fibrous sheet called Interosseous membrane More/less movable than that of sutures/gomphoses Examples: radius to ulna (a more movable one, Amphiarthrosis) allow supination and pronation (next slide); tibia to fibula (less movable one) Tibia & fibula Syndesmosis

Supination and Pronation For example: In the forearm Supination rotation of forearm so that the palm faces forward Pronation rotation of forearm so the palm faces to the rear A B Supine means up. In order to carry a bowl of soup, your hand must be in the supine position

Check point question #1-- Functionally, why are sutures classified as synarthroses, and syndesmoses as amphiarthroses? 9-21

§ 3. Cartilaginous Joints (amphiarthrosis) Two bones are linked by cartilage Two types– A. synchondroses and B. symphyses

Cartilaginous Joint – A. Synchondrosis Bones are joined by hyaline cartilage Examples: First rib attachment to sternum (A on the right) Temporary joint between epiphysis and diaphysis in growing bones: called Epiphyseal ?__________ A B, next

Cartilaginous Joint – B. Symphyses 2 bones joined by fibrocartilage Examples: See figure at right Only slight amount of movement is possible Examples– 1 & 2 on the right 2 1

Check point question #2-- What is the structural difference in histology between a synchondrosis and a symphysis? 9-25

IV. Focusing on synovial joints

§ 4. Synovial Joint Most are freely movable; two bones in fact Do / Do not touch each other Two bones are separated by a space called A. _________ cavity (with fluid in it) and a soft tissue called B._____________ B. Articular cartilage -- hyaline cartilage covering the joint surfaces Synovial fluid —a lubricant; feeds cartilages B A Next slide

§ Synovial joints Joint (Articular) capsule encloses joint cavity (Outer) Fibrous capsule: continuous with periosteum (Inner) synovial membrane; secretes ____________ Articular discs or menisci: cartilage grows inward and forms pads (Fig. 9.29 c-d; 8.39) jaw, wrist, sternoclavicular and knee joints absorbs shock, guides bone movements and distributes forces Tendon: attaches muscle to bone Ligament: attaches bone to bone

Knee Joint

Right Knee Joint – Superior View PCL Medial meniscus & lateral meniscus absorb shock and shape joint ? ACL Lateral condyle of tibia Medial condyle of tibia

Anterior view Posterior view 9-31

§ Tendon Sheaths and Bursae Bursa = a sac filled with synovial fluid Tendon sheaths = elongated bursae lined with synovial membrane and wrapped around a tendon Ulnar bursa Tendons (flexor digitorum) Tendon sheaths

Tendon Sheaths and Bursae Bursa = a sac filled with synovial fluid (Locations) between muscles or between a tendon & a bone etc.; Good examples– Shoulder joint etc. Fig. 9.24 Tendon sheaths = elongated bursae (Locations) where there is considerable friction; such as the hand, wrist, fingers, the ankle, foot, toes etc. Functions of bursa and tendon sheaths: Reduce friction in joints (such as the shoulder), Cushion the movement of one body part over another

Fig. 9.24 Humeroscapular joint

Check point question #3-- A) What is the functional classification of synovial joints? B) Why is a meniscus in an interphalangeal joint unnecessary? 9-35

V. Types of synovial joints

§ 6 Types of Synovial Joints—in descending order of mobility 1.

1. Ball-and-Socket Joints Features: Smooth hemispherical head fits within a cuplike depression Examples: (shoulder) head of humerus into glenoid cavity of scapula (hip) head of femur into acetabulum of hip bone Type: only multiaxial joints in the body Demonstration: (next slide)

Planes of movement (A-C) & axes of rotation Shoulder joint has 3 degrees of freedom = multiaxial joint; Other joints – monoaxial or biaxial Axis of rotation– Def.--perpendicular to the plane of movement; examples— A, B, C A The arm rises in the frontal plane C B The arm rotates in the transverse plane The arm moves through the sagittal plane

Planes of movement & axes of rotation A—Abduction (away from midline) vs. adduction B—Flexion (decreases a joint angle) vs. extension C—Medial (internal) rotation vs. lateral rotation The arm rises in the frontal plane C B The arm rotates in the ______ plane It moves through the _________ plane

2.

2. Condyloid (ellipsoid) Joints Features: Oval convex surface on one bone fits into a similarly shaped depression on the next Examples: radiocarpal joint of the wrist metacarpophalangeal joints at the bases of the fingers Type: Biaxial joints– why? Demonstration: index finger (or 2nd - 5th digits) and Fig. 9.21

    Metacarpophalangeal joints When someone is abducted, they are taken away, just as abduction takes the limb away from the body. During adduction, the limb is added to the body.     Metacarpophalangeal joints

3.

Condyloid joint  

3. Saddle Joints Features: Each articular surface is shaped like a saddle, concave in one direction and convex in the other bone (like a sitting rider) Examples: trapeziometacarpal joint at the base of the thumb Type: Biaxial joint (see demo below) Demonstration: A) frontal plane (palmar abduction) B) sagittal plane (opposition) primates’ anatomical hallmark: __________ Fig. 1.5 & 9.21 c-d

Primate adaptations: Monkey The thumbs became opposable; they made the hands prehensile Human

Figure 9.21d  ID this movement of thumb

Figure 9.21e  ID this movement of thumb

4.

4. Gliding (plane) Joints Features: Flat articular surfaces in which bones slide over each other Examples: Fig. Z tarsal bones between the carpal bones of the wrist, the tarsal bones of the ankle, articular processes of the vertebrae Type: Biaxial joints Demonstration: head is tilted side-to-side and back-and-forth, the vertebrae slide accordingly

Can Talented Naval Medics Interest Lazy Cubs? Calcaneus Talus Cuboid (Intermediate) (Lateral) Medial cuneiform Gliding

5.

Anterior view Capitulum Funny bone

5. Hinge Joints Features: One bone with convex surface that fits into a concave depression on other bone Examples: ulna and humerus at elbow joint (trochlea of the humerus fits into the trochlear notch of the ulna) femur and tibia at knee joint (tibiofemoral) finger and toe joints (interphalangeal) Type: Monaxial (uniaxial) joints Fig. 9.25b

A hinge joint --the elbow (Trochlear notch)

6.

6. Pivot Joints Features: One bone rotates on its longitudinal axis relative to the other Examples: proximal radioulnar joint; the radius pivots during pronation and supination atlantoaxial joint (dens of axis to atlas); Fig. 8.24 (rotation of the atlas) Type: Monaxial joints Demonstration: see next 3 slides

Supination and Pronation For example: In the forearm Supination rotation of forearm so that the palm faces forward Pronation rotation of forearm so the palm faces to the rear   A B

of the atlas (the next slide)

Anterior arch (C1) ? (C2)

Check point question #4-- Which of the 6 type of synovial joints are biaxial? Give one specific example for each biaxial synovial joint. 9-65

Questions (muddiest points)?