Joints of the limbs

Question 1

Define and give examples: Synostosis

Answer 1

Fusion of two bones (like fusion of the sacral vertebrae)

Question 2

Define and describe a fibrous joint

Answer 2

A joint where bones are joined by a collagenous fibrous or fibroelastic tissue

No movement

Question 3

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Pivot joint

Answer 3

Rounded portion of bone enclosed by a ring formed by ligament and bone. Uniaxial (rotation around the axis). Atlantoaxial joint, rotation of atlas around axis.

Question 4

Define and give examples: Synarthrosis

Answer 4

Joint that is functionally classified as immobile (like sutures of skull)

Question 5

Define and give examples: Diarthrosis

Answer 5

Joint that is functionally classified as freely mobile and so will be a synovial joint (like the shoulder joint)

Question 6

Define and give examples: Amphiarthrosis

Answer 6

Joint that is functionally classified to have limited mobility (like the cartilaginous joint between adjacent vertebrae)

Question 7

Define and give examples: Syndesmosis

Answer 7

Fibrous joint in which two parallel bones are united by fibrous connective tissue, allowing limited mobility (like the interosseous membrane linking the radius and ulna)

Question 8

Define and give examples: Synchondrosis

Answer 8

Primary cartilaginous joint where bones joined together by hyaline cartilage (like the temporary joint formed between the epiphysis and the diaphysis of the femur during infancy)

Question 9

Define and give examples: Symphysis

Answer 9

Secondary cartilaginous joint where bones are joined by fibrocartilage (like the pubic symphysis)

Question 10

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Hinge joint

Answer 10

Concave articular surface articulates with a convex articular surface. Uniaxial (flexion and extension in one axis). Elbow joint at trochlea of humerus with trochlea notch of ulna.

Question 11

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Saddle joint

Answer 11

Two saddle shaped bones articulating at the superior surface of the saddle. Saddle characterised by begin convex in coronal plane and concave in sagittal plane, so movement permitted is rolling laterally and rocking forwards/backwards.
Therefore, biaxial.
Joint between trapezium ad metacarpal bone of the thumb

Question 12

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Plane joint

Answer 12

Articulating surface of bones are flat or slightly curved, and they slide over one another, giving multiaxial movement only restricted by surrounding ligaments of bones.
Joints between the carpals and tarsals, as well as the acromioclavicular joint

Question 13

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Condyloid joint

Answer 13

Ovoid articular surface (that’s specifically not spherical) received by elliptical depression, permitting biaxial movement (flexion/extension, adduction/abduction)
Distal radius with scaphoid and lunate, or metacarpophalangeal joints

Question 14

Define the following synovial joints, give examples of where they are found and what kind of movements they permit: Ball-and-socket joint

Answer 14

Greatest range of motion, spherical head received by concave hollow
Only two ball-and-socket joints are the shoulder and hip joint, permitting flexion/extension, abduction/adduction and rotation, therefore multiaxial

Question 15

Define and describe a cartilaginous joint

Answer 15

Primary = bones united by hyaline cartilage (like the first rib with the manubrium) - no movement
Secondary = surface of articulating bones covered in hyaline cartilage, and the two surfaces are separated by fibrocartilage (like the intervertebral discs or the pubic symphysis) - small amount of movement permitted

Question 16

Define and describe a synovial joint

Answer 16

Joint cavity located between two articular surfaces, filled with synovial fluid. Joint cavity formed by a fibrous joint capsule which attaches near the margins of the articular surfaces. Ligaments can also reinforce the joint capsule either within it (intrinsic) or outside it (extrinsic). On the inferior surface of the joint capsule is located the synovial membrane (which also lines any other interior surfaces which are not articular surfaces). It secretes synovial fluid.

Lots of mobility

Question 17

What is the difference between a simple, complex and compound joint?

Answer 17

Simple: just two articulating bones
Complex: two articulating bones, separated by an articular disc/meniscus
Compound: where there are more than two articulating bones

Question 18

What factors affect stability and mobility?

Answer 18

• Shape of articular surfaces
• Presence of ligaments restricting certain movements
• Presence of muscles providing active opposition of opposing movement and promotion of other movements
• Presence of articular discs
• Presence of synovial membrane
• Presence of bursae to allow frictionless movement

Question 19

Describe the sternoclavicular joint, mentioning:

• type
• articulations
• contents of joint
• ligaments
• muscles
• movements

Answer 19

• synovial, complex, saddle joint
• formed by saddle shaped clavicular facet of sternum (and superior surface of first costal cartilage) articulating with the saddle shaped medial surface of the clavicle
• within joint cavity there’s an articular disc running from the superior clavicle joint surface to the superior first costal cartilage
• anterior and posterior sternoclavicular ligaments, found around the joint capsule, the interclavicular ligament which joins the superomedial surfaces of the two clavicles, and the costoclavicular ligament, extending from the superior surface of the first costal cartilage to the inferior surface of the clavicle
• subclavius aids in joint stability, located between the clavicle and the first costal, originating from the first costal and inserting on the subclavian groove of the clavicle
• permits elevation, depression, retraction, protraction and a small degree of rotation (therefore multiaxial)

Question 20

Describe the acromioclavicular joint, mentioning:

• type
• articulation
• ligaments
• movements

Answer 20

• Plane, synovial joint
• Formed between the acromion and the clavicle
• Two acromioclavicular ligaments, one superior and one inferior, running from the acromial end of the clavicle to the acromion; the coracoacromial ligament which runs from the coracoid process to the acromion; the conoid and trapezoid ligaments, which are coracoclavicular ligaments- conoid is more medial and attaches to the conoid tubercle, whereas trapezoid attaches to the oblique ridge on the inferior surface of the clavicle
• allows arm to be raised above the head, and since it attaches scapula to the thorax it increases its range of motion

Question 21

Describe the shoulder joint, mentioning:

• type
• articulations
• special features of joint capsule and ligaments
• muscle attachments
• movements

Answer 21

• ball-and-socket synovial joint
• head of the humerus and the shallow glenoid fossa
• glenoid labrum is a rim of fibrocartilage that slightly deepens the joint; remarkably thin joint capsule extending from rim of glenoid to the anatomical neck of the humerus; strong thickening of the capsule is the coracohumeral ligament which helps in supporting the weight of the arm; additional support provided by glenohumeral ligaments , which wrap around the glenoid anteriorly to posteriorly from the medial surface of the humeral head
• muscles contribute most to the stability of the shoulder joint
• ->long head of biceps brachii tendon travels through intertubercular sulcus and through joint cavity to attach to glenoid labrum
• ->rotator cuff muscles supraspinatus, infraspinatus and teres minor inserting on greater tubercle of humerus and subscapularis (anterior muscle) inserting on lesser tubercle of humerus
• multiaxial, all directions, permitted by shallow socket and not very strong ligaments limiting motion, using muscles for active stabilisation

Question 22

Describe the hip joint, mentioning:

• type
• articulations
• special features of joint capsule
• ligaments

Answer 22

• synovial, ball-and-socket joint
• spherical head of femur articulates with deep cavity called the acetabulum
• acetabulum deepened by the acetabular labrum, which grip around the head of the femur; joint capsule runs from the rim of acetabulum to the neck of the femur
• three extrinsic ligaments: iliofemoral ligament, which is V shaped and curves anteriorly, inserting posteriorly on iliac body and twice on intertrochanteric line; pubofemoral ligament which is also anterior, running from superior pubic ramus to inferior femoral neck; and ischiofemoral ligament, which is posteriorly located coming from the ischial body, and is spiral shaped so it screws tighter on extension of the hip

Question 23

Describe the elbow joint, mentioning:

• type
• articulations
• joint capsule and ligaments

Answer 23

• synovial, hinge joint
• articulation of radial head with capitulum (surface of lateral condyle) and articulation of trochlea notch of ulna with the trochlea of humerus- hinge created by the latter articulation, as the olecranon of the ulna wraps around the trochlea to articulate with the olecranon fossa posteriorly in extension, and during flexion the coronoid process articulates with the coronoid fossa anteriorly
• the articular capsule surrounds the whole joint , and attaches to the annular ligament which runs from the coronoid process to the lateral side of the ulna, wrapping over the head of the radius; capsule thickens into the triangular radial collateral ligament laterally (emerging from lateral epicondyle and attaching to lateral side of ulna and annular ligament) and ulna collateral ligament medially (made of three ligaments, one emerging from medial epicondyle and attaching to coronoid process, one attaching the UCL distally and wrapping round to attach to olecranon, and one emerging from medial epicondyle and attaching to medial side of proximal ulna) to prevent excessive lateral/medial movement of joint (hence hinge joint)

Question 24

Describe the knee joint, mentioning:

• type
• articulations
• synovial cavity
• joint capsule
• ligaments
• muscles

Answer 24

• complex, bicondyloid synovial joint, allowing flexion, extension and a small degree of medial/lateral rotation
• formed by the articulation of the two wheel-shaped condyles of the femur and the two flat condyles of the tibia, as well as a plane joint between the patella and the distal femur (femoropatellar joint)
• complex synovial cavity with a number of bursae; two menisci made of fibrocartilage, shaped like two “Cs” pointing to one another, are attached to the articular surface of the tibia, and they serve to even out compressive load and synovial fluid, as well as guide the movement of the condyles of the femur to prevent rocking; two intracapsular ligaments, ACL (from intercondylar region of tibia anteriorly to medial portion of lateral condyle of femur posteriorly) and PCL (from intercondylar region of tibia posteriorly to attach to lateral side of medial condyle of femur)- these prevent excessive movements
• articular capsule only present posteriorly, covering most of the condyles of the femur and tibia
• 3 ligaments take the place of an anterior joint capsule- the patellar ligament continuing from the quadriceps tendon to the anterior tibia, and the two flanking medial and lateral patellar retinacula. Additionally, the fibular collateral ligament extends from the lateral epicondyle of the femur to the head of the fibula, and the tibial collateral ligament extends from the medial epicondyle of the femur to the medial condyle of the femur. The oblique popliteal ligament is a continuation of the semimembranosus muscle reinforcing the joint capsule posteriorly and the arcuate popliteal ligament runs from the posterior head of the fibula to the posterior joint capsule
• tendons of quadriceps femoris and semimembranosus most important in providing active stabilisation of knee joint