The Principles of Articulation Flashcards
1
Q
Define the following:
Synarthrosis
Amphiarthrosis
Diarthrosis
A
- Synarthrosis: immovable
- Amphiarthrosis: partially moveable
- Diarthrosis: freely moveable
2
Q
Describe Fibrous joints
- subdivisions
A
- No synovial cavity
- Held together by a fibrous connective tissue
- Permits little or no movement (synarthrosis/amphiarthrosis)
- Three types of fibrous joint:
- Suture
- Syndesmosis
- Interosseous membrane
3
Q
Describe Fibrous joints - Suture
A
- Unite skull bones
- Thin layer of dense connective tissue
- Irregular
- Interlocking edges provide strength, permit no movement (synarthrosis)
- Ossification of a suture forms a synostosis
- e.g. left & right sides of frontal bone fuse ~6 years of age
4
Q
Describe Fibrous joints- Syndesmosis
- examples
A
- More connective tissue than seen in a suture
- Crosses a greater distance than a suture
- Connective tissue typically arranged into bundles (ligament)
- Typically permit slight movement (amphiarthrosis)
- example
- Distal tibiofibular joint: connected by the tibiofibular ligament
- Gomophosis (dentoalveolar): connective tissues is called periodontal ligament
5
Q
Describe Fibrous joints: Interosseous membranes
- example
A
- Sheet of dense connective tissue
- Binds adjacent long bones
- Amphiarthrosis
- Two main examples between the radius and ulna in forearm, and tibia and fibula in the leg
6
Q
Describe Cartilaginous joints
- different types
A
- No synovial cavity
- Held together by fibrocartilage or hyaline cartilage
- hyaline cartilage is more synarthrotic
- Permits little or no movement (synarthrosis/amphiarthrosis)
- Two types of cartilaginous joint:
- Synchrondosis
- Symphysis
7
Q
Describe Cartilaginous joints: Synchrondosis
- example
- clinical relevance
A
- The connective tissue is hyaline cartilage
- Synarthrosis
- Example: epiphyseal plate (growth plate)
- At skeletal maturity the epiphysis, metaphysis and epiphyseal plate fuse forming a synostosis become stronger and more solid
8
Q
Describe Cartilaginous joints: Symphysis
- example
A
- Connective tissue is fibrocartilage
- Adjacent bones lined with hyaline cartilage, but with a broad disc of fibrocartilage connects the bones
- Amphiarthrosis
- All symphysis occur in the midline of the body:
- Junction of the manubrium and sternum
- Intervertebral discs
- Pubic symphysis
9
Q
Describe Synovial joints
A
- Synovial (joint) cavity between articulating bones
- Freely moveable - diarthrosis
- Layer of hyaline cartilage called articular cartilage lining the bone
- there is an additional lining cartilage at the knee
10
Q
Describe the role and structure of Articular cartilage
A
- Covers the bones at synovial joints
- Avascular (no point)
- Composed of collagen and proteoglycan
- Orientation of collagen structure impairs resistance to compression & an extremely low resistance surface
- arches of chondrocytes gives it a strong structure
11
Q
Describe the role and structure of the Articular capsule
A
- Encapsulates a synovial joint
- Composed of two layers
-
Outer fibrous membrane connects to the periosteum of the bone
- Flexibility permits movement
- Fibres arranged into bundles – high tensile strength
-
Inner layer termed synovial membrane
- areolar connective tissue rich in elastic fibres
- occasionally contains structural articular fat pads
12
Q
Describe the role and composition of Synovial fluid
A
- Secreted by the synovial membrane
- Rich in hyaluronic acid, secreted by fibroblast-like cells, and interstitial fluid from blood plasma
- Lubricates articular surface – reducing friction
- Provides some shock-absorbing properties
- Supplies nutrition to, and removes waste products from the avascular articular cartilage
- Phagocytes remove microbes and debris
13
Q
What are the types of Accessory ligaments found at the synovial joint
-example
A
- Intracapsular ligaments lie within the joint capsule
- Excluded from the synovial fluid by folds in the synovial membrane
- e.g. anterior and posterior cruciate ligaments of the knee
- Extracapsular ligaments lie outside the joint capsule
- e.g. fibular and tibial collateral ligaments of the knee
14
Q
What is the role and structure of Accessory articular discs at Synovial joints?
- example/ clinical relevance
A
- Fibrocartilage pads lie between articular cartilage of some synovial joints e.g.meniscus of the knee
- Called meniscii or articular discs
- Help maintain joint stability
- Direct the flow of synovial fluid
- meniscal tears are common in athletes: important to try and maintain as much of it as possible as if removed –> osteoarthritis
15
Q
What are the key nerve and blood supply points about synovial joint structures
A
- Nerve endings same as those that supply associated muscles
- Distributed to the articular capsule and associated ligaments
- Aid in Pain and proprioception
- Many components of the synovial joint are avascular
- Rely on numerous branching of arteries and veins to supply associated tissue
18
Q
Describe a Hinge Synovial joint
- examples (2)
A
- Concave surface of one bone fits the convex surface of another
- Permits motion in a single axis (flexion and extension)
- Examples include:
- knee joints
- elbow joints
19
Q
Describe a Pivot Synovial joint
- examples (2)
A
- Rounded or pointed surface of one bone pivots inside a ring formed by the other bone and a ligament
- Permits rotation in its the longitudinal axis (monoaxial)
- Examples include:
- radioulnar joints
- atlanto-axial joint
- allows shaking of the head
20
Q
What is the Atlanto-axial joint?
A
- Dens of the axis slots into and against the atlas,
- bounded by the transverse atlantal ligament
- allows shaking of the head
22
Q
Describe a Saddle Synovial joint
- examples (1)
A
- One bone fits into the saddle-shaped bone it opposes
- Modified condyloid joint
- Permits movement around two-axis (biaxial; flexion and extension, abduction and adduction, (sometimes limited rotation))
- Examples include:
- carpometacarpal joint
24
Q
Describe a Condyloid Synovial joint
- examples (2)
A
- Convex oval projection of one bone fit into the oval depression of the other.
- Permits movement around two axis (biaxial; flexion and extension, and abduction and adduction)
- Examples include:
- wrist joint
- metacarpophalangeal joints
25
Q
What is the role of the Glenohumeral joint
- type of joint
- structure
- ligaments
A
- Synovial ball and socket joint
- Joint between the proximal humerus and the scapula (glenoid fossa)
- Due to the shallowness of the glenoid cavity, it is the most mobile joint in the body
- Glenoid labrum; a narrow rim of fibrocartilage – deepens glenoid
- Stabilised by three ligaments:
- glenohumeral
- coracohumeral
- transverse humeral
- Four associated bursae
- more strength provided by the Rotator cuff muscles
26
Q
What is the role of the Acromioclavicular joint
- type of joint
- structure
- ligaments
A
- Technically a synovial gliding joint (planar) but it acts like a pivot
- Joint between the acromion (part of the scapula) and the clavical
- Stabilised by three ligaments:
- acromioclavicular
- coracoacromial
- coracolclavicular (conoid and trapezoid)
- Allows the movement of the scapula, permitting greater arm rotation (above the head)
27
Q
What is the role of the Sternoclavicular joint
- type of joint
- structure
- ligaments
A
- Synovial saddle joint
- Although a saddle joint – is capable of triaxial movement – all movement is passive
- Medial clavicle fits into a hollow formed by the superolateral surface of the manubrium and the medial costal cartilage of the first rib.
- The fibrocartilagenous articular disc divides the joint into two synovial cavities
- Reinforced by ligaments
- interclavicular, anterior, and posterior sternoclavicular ligaments
28
Q
What are the 3 ligaments of the glenohumeral joint?
- structure/ role
A
- Glenohumeral ligaments: superior, middle and inferior ligaments are thickenings of the joint capsule
- Coracohumeral ligament: joins superior joint capsule to the coracoid process
- Transverse humeral ligament: bridges bicipital groove, stabilizing bices tendon
