MSK 2 Classification of and Joints of Upper limb Flashcards
What type of bone is the frontal bone of the skull?
Flat bone
What type of bone is the scaphoid?
Short bone
What type of bone is the humerus?
Long bone
What type of bone is a vertebrae?
Irregular bone
What type of bone is the patella?
Sesamoid bone
What is a sesamoid bone?
Bone embedded within a muscle or tendon
What type of bone is embedded within a cranial suture?
Sutural bone
Define joint:
A articulation between either:
- Neighbouring bones
- Teeth and bone
- Cartilage and bone
What are the main characteristics of a fibrous joint?
- No synovial cavity
- Articulating bones held close by fibrous tissue
- Little or no movement
Name the 3 types of fibrous joints:
- Syndesmosis
- Gomphosis
- Suture
What are the main characteristics of a cartilaginous joint?
- No synovial cavity
- Articulating bones tightly connected via cartilage
- Little or no movement
Name the 2 types of cartilaginous joints:
1) Synchondrosis
2) Symphysis
What type of cartilage is present within a synchondrosis?
Hyaline cartilage
What type of cartilage is present within a symphysis?
Fibrocartilage
What is the functional classification of a synchondrosis?
Synarthrosis
What is the functional classification of a symphysis?
Amphiarthrosis
What are the main characteristics of a synovial joint?
- Synovial cavity = Articular cartilage + capsule
- Bursa/tendon sheaths
- Freely movable (Diarthrosis)
What are the 3 ways to functionally classify a joint?
1) Synarthrosis
2) Amphiarthrosis
3) Diarthrosis
What type of joint is a ‘diarthrosis’?
Freely movable (synovial joint)
What type of joint is an amphiarthrosis?
Permits little movement (may be fibrous or cartilaginous)
What type of joint is a synarthrosis?
Permits no movement (may be fibrous or cartilaginous)
What type of cartilage is usually present within a synovial joint?
Hyaline cartilage
Why is it important for a synovial joint to have a rich blood supply?
Synovial joints are freely movable, so must receive good blood supply to prevent loss of perfusion during flexion
Approximately how much synovial fluid is present within a synovial joint?
~ 0.5 ml
What 4 substances make up synovial fluid?
- Hyaluronic acid
- Proteinases
- Collagenases
- Lubricin
Name the 6 types of synovial joint:
1) Ball-and-Socket
2) Pivot
3) Planar
4) Saddle
5) Hinge
6) Condyloid/Ellipsoidal
Classify the sternoclavicular joint:
Planar synovial joint
Diarthrosis
Classify the knee joint:
Hinge synovial joint
Diarthrosis
Classify the Atlo-axial joint:
Pivot synovial joint
Diarthrosis
Classify the wrist joint:
Condyloid/Ellipsoidal synovial joint
Diarthrosis
Classify the Atlanto-Occipital joint:
Condyloid/Ellipsoidal synovial joint
Diarthrosis
Classify the joint between the trapezium and the base of the 1st metacarpal:
Saddle synovial joint
Diarthrosis
Classify the shoulder joint:
Ball-and-Socket synovial joint
Diarthrosis
Define Hilton’s Law:
The nerves supplying a joint also supply the muscles moving the joint, and the skin overlying the insertions of these muscles
What causes the popping sound heard when joints are ‘cracked’?
- Bones are pulled away from each other
- Synovial cavity expands but synovial fluid volume stays constant, producing a vacuum
- The gases dissolved in the synovial fluid are pulled out of solution = POP
What are the articulating surfaces of the glenohumeral joint?
- Glenoid cavity of the scapula
- Head of the humerus
What is the glenoid labrum?
Ring of fibrocartilage surrounding the rim of the glenoid cavity = deepens the cavity to stabilise glenohumeral joint
Name the 4 rotator cuff muscles:
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
Which rotator cuff muscle inserts into the lesser tubercle of the humerus?
Teres minor
Which rotator cuff muscles insert into the greater tubercle of the humerus?
Supraspinatus
Infraspinatus
Subscapularis
Which 7 muscles contribute to the glenohumeral joint?
1) Supraspinatus
2) Infraspinatus
3) Subscapularis
4) Teres minor
5) Deltoid
6) Long head of Biceps brachii
7) Long head of Triceps brachii
Name the 3 extracapsular ligaments of the glenohumeral joint:
Coracoacromial ligament
Coracohumeral ligament
Transverse ligament
Name the 3 intracapsular ligaments of the glenohumeral joint:
Superior glenohumeral ligament
Middle glenohumeral ligament
Inferior glenohumeral ligament
Where does the glenohumeral joint capsule attach to?
Glenoid labrum
Laterally: Anatomical neck of humerus
Medially: Surgical neck of humerus
The glenohumeral joint capsule is continuous with which bursa?
Subscapular bursa
What 3 structures form the Coracoacromial arch?
1) Coracoacromial ligament
2) Acromion
3) Coracoid process
Which STRONG glenohumeral ligament prevents upper displacement of the humerus?
Coraco-acromial ligament
Name the 2 bursae within the glenohumeral joint:
Subscapular bursa
Subacromial bursa
Name the 4 muscles which cause flexion at the glenohumeral joint:
1) Deltoid (anterior fibres)
2) Biceps brachii
3) Coracobrachialis
4) Pectoralis major
Name the 3 muscles which cause extension of the glenohumeral joint:
1) Triceps brachii
2) Latissimus dorsi
3) Teres major
Which muscle causes abduction of the arm from 0’ to 15’?
Supraspinatus
Which muscle causes abduction of the arm from 15’ to 90’?
Deltoid
What causes abduction of the arm 90’+?
Serratus anterior
Trapezius
Scapular rotation
Which muscles cause adduction of the arm?
Lattisimus dorsi
Pectoralis major
Teres major
Which muscles cause medial rotation of the arm?
Subscapularis
Teres major
Pectoralis major
Latissimus dorsi
Which muscles cause lateral rotation of the arm?
Infraspinatus
Teres minor
Which arteries supply the glenohumeral joint?
Anterior and Posterior Circumflex humeral arteries
Suprascapular artery
Which nerves supply the glenohumeral joint?
Suprascapular nerve
Axillary nerve
Lateral pectoral nerve
Where is the safe area for injection into the deltoid muscle? What are you trying to avoid?
Over 4cm below the acromion
Avoid damage to axillary nerve and circumflex humeral arteries
What are the 2 causes of a posterior dislocation of the humerus?
1) Epilepsy
2) Electrocution
What is the main cause of an anterior dislocation of the humerus?
Trauma on fully abducted arm
How would someone present with an anterior dislocation of the humerus, and why?
Painful, arm supported,
Square shoulder - humeral head pulled below coracoid process due to pectoralis major and teres major
What is the most common cause of a surgical neck fracture of the humerus?
Fall on outstretched hand
Which nerve is at risk during anterior dislocation of the humerus?
Axillary nerve
Which nerve is at risk during a surgical neck fracture of the humerus?
Axillary nerve
What is the presentation of painful arc syndrome?
Painful abduction of arm between 50’ to 130’
What is the main cause of painful arc syndrome?
Repetitive overuse: sports/overhead work ie plastering