L3 Classification of joints Flashcards
What are the four types of joints?
- Fibrous
- Primary cartilaginous
- Secondary cartilaginous
- Synovial
How is bone joined to bone in primary cartilaginous joints?
By hyaline cartilage
Give three examples of primary cartilaginous joints
- Costochondral
- 1st sternochondral
- Spheno-occipital
What two joint types aren’t very movable?
- Fibrous
- Primary cartilaginous
What two joint types are very movable?
- Secondary cartilaginous
- Synovial
What is the sequence of secondary cartilaginous joints?
bone ↔ hyaline cartilaginous plate ↔ fibrocartilagenous disc ↔ hyaline cartilage plate ↔ bone;
Where are secondary cartilaginous joints normally found?
In the midline of the body uniting bones of the axial skeleton
In secondary cartilaginous joints between adjacent vertebral bodies, what does the central portion consist of?
Concentric rings of fibrocartilage (annulus fibrosus) surrounding a central gelatinous core (nucleus pulposus)
What occurs in degenerative disc disease?
The outer annulus weakens and micro-tears form – eventually the annular fibrous portion can rupture allowing the central gelatinous core to herniate aka - slipped disc!
What can disc herniations cause?
Can press on to emerging nerve roots and lead to weakness in distal limb muscles and numbness and tingling (paresthesia) in the skin
NBBBB!!!!What are the differences between a typical and an atypical synovial joint (articular surfaces)?
Typical: has articular surfaces of two bone ends enclosed in a fibrous capsule, articular surfaces of the bone ends are lined by hyaline cartilage
Atypical: the articular surfaces of the bone ends are lined by fibrocartilage and the inside of the capsule and all non-articular surfaces are lined by synovial membrane.
What are the predominant types of synovial joints?
BCHMPP
- Plane
- Hinge
- Modified hinge
- Condyloid
- Saddle condyloid
- Pivot
- Ball and socket
What movement(s) are plane synovial joints capable of?
Gliding
What movement(s) are hinge synovial joints capable of?
- Flexion
- Extension
What movement(s) are modified hinge synovial joints capable of?
- Flexion
- Extension
- Rotation with flexed knee
What movement(s) are condyloid synovial joints capable of?
- Flexion
- Extension
- Abduciton
- Adduction
- Circumduction
What movement(s) are saddle condyloid synovial joints capable of?
- Flexion
- Extension
- Adduction
- Abduction
- Circumduction
- ‘Controlled’ rotation = opposition
What movement(s) are pivot synovial joints capable of?
Rotation (uni-axial)
What movement are ball and socket joints capable of?
- Flexion
- Extension
- Adduction
- Abduction
- Circumduction
- ‘Free’ rotation
Give two examples of a plane joint
- Tarsus
- Carpus
Give an example of a hinge joint
Interphalangeal
Give an example of a modified hinge joint
Knee
Give an example of a Condyloid
Metacarpophalangeal
Give an example of a saddle condyloid
1st carpometacarpal
Give two examples of a pivot joint
- Both ends of radius
- Atlanto-axial
Give two examples of a ball and socket joint
- Hip
- Shoulder
What are synovial joints capsules often referred to as?
Capsular ligament
What can synovial joints be strengthened by?
By ligaments intrinsic thickenings of the capsule themselves or by extrinsic ligaments unattached to the capsule
Name five structures that may be found inside some synovial joints
- Ligaments
- Fat pads
- Tendons
- Fibrocartilagenous discs
- Fibrocartilagenous labrum deepening a socket.
Hyaline cartilage characteristic and importance
It is relatively avascular therefore derives its nutrition from flow of synovial fluid into and out its substance during movement
What is the focus of joint rehabilitation?
To restore pain free range of motion
What does cartilage reply on for nutrition?
On joint contact surfaces moving on one another for inflow of oxygen and nutrients and outflow of waste products
What does healthy hyaline cartilage do during contact?
The contact points during motion extrude synovial fluid
What does healthy hyaline cartilage do when not in contact?
Recoil or expansion sucks in synovial fluid
What does the process of cartilage maintain?
The small flow of nutrients and oxygen required and takes away waste products
What does the avascular nature of the cartilage cause in damage?
If the cartilage is damaged during an injury it usually never repairs itself fully
What type of joint is sternoclavicular joint?
Atypical synovial saddle joint
Degrees of freedom for sternoclavicular joint
3 degrees of freedom
What are the articular surfaces of the sternoclavicular joint?
- Medial end of clavicle
- Manubrium of sternum
- 1st costal cartilage
What lines the articular surfaces of the sternoclavicular joint?
Fibrocartilage
What divides the sternoclavicular joint into two cavities?
Complete fibrocartilage disc
What are the capsular ligaments in sternoclavicular joint?
Capsule surrounds joint & epiphysis of bone / capsular ligament is thickened as anterior & posterior sternoclavicular ligaments + disc attaches to clavicle superiorly and costal cartilage/first rib inferiorly, this deepens socket for the clavicle.
What are the intrascapsular structures of the sternoclavicular joint?
Yellow fibrocartilagenous articular disc attached superiorly to (M) end clavicle and inferiorly to junction of 1st costal cartilage and sternum. Disc blends with the anterior & posterior ligaments and prevents the clavicle overriding joint medially, also deepens socket for (M) end of clavicle + acts as shock-absorber, which is why surfaces are covered with fibrocartilage instead of the normal hyaline.
What are the extrinsic ligaments of the sternoclavicular joint?
Costoclavicular - very strong ligament attached from 1st rib & costal cartilage to (I) margin (M) end of the clavicle, reinforces joint + prevents elevation of clavicle.
What are relations of sternoclavicular joint
- Pleura
- Lungs
- Brachiocephailic vein
- Carotid artery
- Subclavian artery
What is the neurovascular supply of the sternoclavicular joint?
Nerve to subclavius (C5,6) & (M) supraclavicular nerve (C4) internal thoracic artery suprascapular artery
Is the sternoclavicular joint stable?
Stable due to very strong ligaments
Clinical of sternoclavicular joint
Rarely dislocated due to strong costo-clavicular ligament, clavicle fractures more often / if subluxed or dislocated suspect major trauma at the root of the neck and upper thorax!
What type of joint is an acromioclavicular joint?
Atypical plane synovial
Degree of freedom in acromioclavicular joint
1 degree of freedom
Articular surfaces of acromioclavicular joint
Oval articular surfaces (facets) slope inferomedially on (L) end of clavicle with reciprocal surfaces on acromion process of scapula.
What lines the articular surfaces of the acromioclavicular joint?
Fibrocartilage
What is inbetween acromioclavicular joint?
incomplete fibrocartilage
Capsular ligament of acromioclavicular joint
Attached to articular margins of bones, strengthened above by a superior acromioclavicular ligament & fibres of trapezius.
Intrascapular of acromioclavicular joint
Synovial membrane lines fibrous capsule.
Articular Disc: Incomplete - wedge-shaped , extends from posterolateral edge.
Extrinsic ligaments of acromioclavicular joint
Coracoclavicular ligament anchors (L) end of clavicle to the coracoid process of scapula;
2 Parts: conoid (conical) & trapezoid (strap) very strong - prevents loss of contact at joint.
Types of muscles and movements in acromioclavicular joint
Simple gliding movements & slight rotation with scapula & shoulder girdle
Relations of acromioclavicular joint
- Subacromial space and bursae
- Supraspinatus muscle /tendon
Neurovascular supply of acromioclavicular joint
Blood Supply: Articular branches of suprascapular artery and thoracoacromial artery.
Nerve Supply: Lateral pectoral nerve / supraclavicular nerve / Axillary nerve
Is the acromioclavicular joint stable?
Inherently unstable
What is stability in the acromioclavicular joint dependent on?
Stability is dependent on extrinsic coracoclavicular ligaments.
Clinical in acromioclavicular joint
Dislocation is common by direct force in contact sports such as rugby, soccer, ice hockey.
Acromioclavicular is common with falls onto the shoulder and generally not serious. Coracoclavicular rupture is serious, needs surgical repair
What type of joint is the glenohumeral joint
Synovial ball & socket joint with 3 degrees of freedom.
What are the articulating surfaces of the glenohumeral joint
Shallow glenoid cavity of the scapula and fibrocartilag
Describe the capsular ligament of the glenohumeral joint
Attached to the scapula beyond the glenoid labrum and medial to the supraglenoid tubercle (thus tendon of long head of biceps is intracapsular) and over to the anatomical neck of the humerus except inferomedially, where it is attached 1.5 cm down the surgical neck this allows some slack for abduction. There are some deficiencies in the capsule one at the exit point of the long head of biceps and secondly anteriorly where the joint cavity communicates with subscapular bursa.
What are the intrinsic and extrinsic ligaments of the glenohumeral joint?
Capsule is strengthened by 3 capsular thickenings the glenohumeral ligaments (superior, middle & inferior) / coracohumeral ligament / transverse humeral ligament long head of biceps passes under capsule.
What are the intrascapular structures
Synovial membrane: attached at margins of articular surfaces and reflected onto internal labral surface. Extends inferiorly into the intertubercular groove of the humerus, as a sheath around the tendon of the long head of biceps and anteriorly into subscapularis bursa. Glenoid labrum – acts as a supporting structure, tendon of long head of biceps is intracapsular but extra synovial
What are the muscles and movements of the glenohumeral joint?
Rotator Cuff Group - Supraspinatus, Infraspinatus, Subscapularis, Teres Minor - all inserted into capsule of joint, act as much to stabilise as to move. 1˚Movers - Pectoralis major, latissimus dorsi, deltoid and teres major. The tendon of the long head of biceps assists by passing through the capsule in the intertubercular sulcus to insert onto the supra-glenoid tubercle. Actions of all muscles dependant on starting position of the limb - 10º of humeral movement associated with 5º of scapular movement - full abduction necessitates lateral rotation.
What muscles cause flexion in the glenohumeral joint?
- Pectoralis major (clavicular head)
- Deltoid, anterior fibres.
What muscles cause extension in the glenohumeral joint?
- Pectoralis major (sternocostal head)
- Deltoid
- Posterior fibres latissimus dorsi
- Teres major.
What causes abduction in glenohumeral joint?
- Deltoid (all fibres): – greater than 15º
- Supraspinatus - between 0º and 15º
What causes adduction in glenohumeral joint?
- Pectoralis major
- Latissimus dorsi
- Teres major.
What causes medial rotation in glenohumeral joint?
- Pectoralis major
- Latissimus dorsi
- Teres major
- Deltoid - anterior fibres.
What causes lateral rotation in glenohumeral joint?
- Deltoid
- Posterior fibres
- Teres minor
- Infraspinatus.
What muscles cause circumduction?
All muscles
Why is the glenohumeral joint stable?
Due to poor bony congruence
Where is the glenohumeral joint weak and why?
Inferiorly due to no real support from muscles
What is the stability of the glenohumeral joint compromised by?
Stability imparted by rotator cuff 40%, prime-movers 40% and intrinsic ligaments / labrum 20%.
Where is the ‘Closed-packed’ and ‘Loose-packed’ ?
‘Closed-packed’ position is in abduction / external rotation and ‘Loose-packed’ when semi-abducted.
What is dynamic stability provided by in the glenohumeral joint?
Provided by rotator cuff muscles and long head of biceps: passive muscle tension plus bulk effect of muscle, restricts movement of head compresses articular surfaces, especially labrum, on contraction increases ‘fit’ plus joint motion causes 2˚ tightening passive ligamentous constraints e.g. glenohumeral ligaments - barrier effect of contracted prime mover muscles, which restricts active arc of motion of limb.
What is static stability provided by in the glenohumeral joint?
Fibro-cartilaginous labrum deepens fossa / shape varies with position of humerus.
Gleno -humeral ligaments, thickened areas of anterior aspect of capsule.
Superior gleno -humeral stabilises against inferior displacement of abducted shoulder.
Inferior glenohumeral stabilises against anterior & anteroinferior displacement of abducted shoulder. Middle glenohumeral, absent in 30%, stabilises against anterior displacement at 45˚ abduction (not effective 0˚ or 90˚ abduction).
What are the relations of the glenohumeral joint?
Bursae: Subacromial / Subscapularis / Infraspinatus.
Nerves: Posterior cord and especially axillary nerve..
Muscles: rotator cuff.
Tendon: long head of biceps
Vascular: Axillary artery and vein.
What is the nerve supply of the glenohumeral joint?
- Axillary nerve (C5, 6)
- Suprascapular nerve (C5,6)
- Lateral pectoral nerve (C5,6,7).
What is the blood supply of the glenohumeral joint?
- Circumflex humeral arteries, from axillary
- Suprascapular artery, from thyrocervical trunk
- Transverse cervical artery from thyrocervical
- 3rd part of axillary may give a subscapular which then divides into circumflex scapular & thoracodorsal arteries.
What is the anterior approach of surgery to the glenohumeral joint?
Deltopectoral groove opened, tributaries of cephalic vein ligated → tip of coracoid process detached and reflected medially → coracho-brachialis /short head of biceps still attached → lateral rotation of humerus → subscap stretched & divided exposing joint (musculocutaneous nerve pierces corachobrachialis / anterior circumflex humeral vessels guide to lower border of subscapularis).
What is the posterior approach of surgery to the glenohumeral joint?
Deltoid detached from spine of scapula and acromion → reflected laterally (axillary nerve and posterior circumflex vessels infraspinatus and teres minor cut exposing
capsule)
