Joints

1. What are the five classifications of bones? Provide an example of each. 

  • Long Bones 

    • Ex: humerus, radius, ulna, femur, metacarpals, and metatarsals 

  • Short Bones 

    • Ex: carpals, tarsals,  

  • Flat Bones 

    • Ex: scapula, ribs, sternum, skull 

  • Irregular Bones 

    • Ex: vertebrae, os coxae, sphenoid] 

  • Sesamoid bones 

    • Ex: Patella 

    • Bones that develop inside of tendons  

 

2. What are the two ways bone is formed?

  • Endochondral Ossification 

    • Formation of bone from a cartilage model 

      • Hyland cartilage 

    • MOST COMMON, almost all bones develop this way 

      • Except for flat bones skull, mandible, and clavicles  

  • Intramembranous Ossification 

    • Bones develop from mesenchymal connective tissue 

    • Forms bones: skull, mandible, and clavicles 

 

3. What are fontanelles? What do these allow for? 

  • Fontanelles are "soft spots" or an area during development in infants where there is a wider area of connective tissue 

  • Allow for: 

    • Flexibility during childbirth 

    • Enlargement of brain during development 

 

4. What are the three anatomical classifications of joints?

  • Synovial (most mobile)

    • Ex: shoulder (glenohumeral), hip (femororacetabular) 

  • Cartilaginous 

    • Ex: intervertebral disc 

  • Fibrous 

    • Ex: skull sutures (strongest) 
       

5. What are the six types of synovial joints? What actions can each do? Examples? 

  • Hinge 

    • Allows flexion/extension 

    • Ex: Ulna/Humerus, interphalangeal 

  • Ball and Socket 

    • Allows for almost every motion 

    • Ex: shoulder and hip 

  • Saddle 

    • Allows special motions of the thumb 

    • Opposition 

  • Plane 

    • Allows joints to glide against one another 

    • Ex: intercarpal, intertarsal 

  • Condyloid 

    • Allows for flexion/extension and adduction/abduction 

    • Ex: wrist, fingers, toes 

  • Pivot 

    • Allows for rotation 

    • Ex: radius/ulna 

 

6. Fill in the blanks: Joints sacrifice movement for stability; or, stability for movement. Explain what this statement means and give examples. 

  • The more stable and secure a joint is, the less room and ability it will have more movement 

 

7. What general factors contribute to the stability and mobility of a joint? 

  • Shape of the bones 

  • Presence of cartilages 

  • Surrounding ligament 

  • Surrounding muscles 
     

8. What is a bursa? Where are they located? 

  • Sacs of synovial fluid outside of the joint capsule, and below the medial and collateral ligaments 

  • Reduce friction between skin and bones & between tendon and bone 
     

9. Describe the general characteristics of a synovial joint. What is a joint capsule? What is the purpose of the synovial membrane?  

  • Synovial Membrane 

    • Slippery fluid that reduces friction 

    • Shock absorber 

    • Provides nutrients and removes waste from cartilage 

  • Articular Cartledge 

    • Made of Hyland cartilage  

    • Smooth, glassy, and reduces friction 

  • Joint Capsule 

    • Periosteum that goes from above joint, surrounds joint, and then attaches down at connecting bone "encapsulating" all of the joint 

  • Bursa 
     

10. Briefly describe the anatomy of the knee joint. What are menisci? What ligaments contribute stability to the joint? Which ligaments are intracapsular? Extracapsular? 

  • Collateral Ligaments 

    • Lateral and Medial 

    • Connect bone to bone with dense regular connective tissue 

    • Extracapsular 

  • Cruciate Ligaments 

    • Anterior and Posterior 

    • Intracapsular 

  • Menisci 

    • Lateral and Medial 

    • Fibrocartilage pad that stabilizes joint  

 

11. What are the functions of the synovial fluid? How does “warming up” affect the synovial fluid and cartilage?  

  • Function of Synovial Fluid 

    • Provides nutrients and removes waste 

      • Does this as you move, when synovial membrane is pressed down, fluid enters blood stream and goes back into joint when pressure is released (like a sponge) 

      • As this movement happening, the synovial fluid "warms up" and goes form being viscous and "egg-white" like, to becoming more thin 

    • Reduces friction 

 

12. What is Rheumatoid Arthritis?  

  • Rheumatoid Arthritis (RA):  

    • Autoimmune disease- Own immune system and WBC attack membranes surrounding joints 

  • Strong correlation with gluten sensitivity 

 

13. What is osteoarthritis? Osteophytes? How can it affect the joint? 

  • Osteoarthritis can occur when there is trauma/overuse to the articular cartilage leaving it roughened so bones rub together 

  • When bones rub together, osteoblasts see the bone as being damaged so they build extra bone on top of "damaged" area where there is friction 

    • Leads to formation of osteophytes (bone spurs) which end up restricting joint movement 

 

14. What type of tissue are tendons and ligaments made of? What is the difference between a tendon and a ligament?  

  • Tendon and Ligaments are made of dense regular connective tissue 

    • Tendon: connects muscles to bone 

    • Ligaments: connect bone to bone 
       

15. What two bones and bone features make up the shoulder (glenohumeral) joint? What is the glenoid labrum? How is the glenoid labrum like a bowl and toilet plunger? What ligaments contribute to the stability of the shoulder joint? What bones/features do each ligament connect? 

  • Glenohumeral joint is made from the glenoid cavity of the scapula and head of the humerus 

  • Glenoid labrum:  

    • Fibrocartilage ring that articulates with the glenoid cavity 

    • Adds stability to joint (glenohumeral) and increases depth and glenoid cavity by 50% 

    • Functions as "bowl" and "plunger" as it gives suction effect and more surface area to keep joint stable 

  • Ligaments that stabilize Glenohumeral Joint 

    • Coracohumeral Ligament 

      • Attaches coracoid process of scapula to humerus 

      • Protects head of humerus from yanking forces 

    • Coracoacromial Ligament 

      • Attaches coracoid process of scapula to the acromion of the scapula  

      • Keeps head humerus in joint when forces push up on humerus 

    • Coracoclavicular Ligament 

      • Attaches coracoid process of scapula to clavicle 

      • Helps anchor the clavicle inferiorly  

    • Acromioclavicular Ligament 

      • Attaches acromion process to clavicle  

      • Shoulder separation = dislocation of this joint 
         

16. What muscles make up the rotator cuff muscles? 

  • Supraspinatus  

  • Infraspinatus 

  • Teres minor 

  • Subscapularis 

 

17. What two bones and bone features make up the hip joint? Compare and contrast the hip joint with the shoulder joint. What similarities do they share? How are they different?  

  • Hip joint made up of acetabulum of os coxae and head of femur 

  • Similarities between hip and shoulder joint  

    • Ball and socket joint  

    • Both have labrum (acetabular labrum and glenoid labrum) 

  • Differences between hip and shoulder joint 

    • Acetabulum is deep compared to glenoid cavity 

    • Larger and stronger ligaments in hip joint 

    • More muscle mass surrounding hip 

    • Hip is more stable and less flexible