Week 2 Flashcards
Which type of joint is the elbow?
Hinge synovial joint
3 elbow joints?
Humeroulnar joint
Humeroradial joint
Proximal radioulnar joint
Elbow movements?
Flexion and extension
Pronation and supination
How is the elbow stable?
Trochlea
Olecranon
Both snugly fit their bones
Where are radius and ulna anatomically, what parts of the elbow do they articulate with?
Radius: lateral, articulates with the capitulum
Ulna: medial, articulates with trochlea
Medial/lateral epicondyles function?
Muscle attachment
Which forearm bone is longer?
Ulna
Two proximal processes of ulna?
Olecranon: larger posterior elbow prominence
Coronoid: smaller, anterior
Notch at proximal ulna?
Trochlear notch: articulates with humerus
Distal parts of ulna?
Head: articulates with radius
Styloid process: wrist ligaments
Why is ulna not part of wrist joint?
Articular disc (fibrocartilaginous ligament) prevents articulation with carpal bones
Which side is the radius on?
Thumb
What is at proximal radius?
Head: articulates with capitulum of humerus and radial notch of ulna
Radial tuberosity: medial, biceps attach here
What is at distal radius? What does it articulate with?
Articulates with ulnar head and proximal carpal bones
Styloid process laterally
Ulnar notch medially
What is the humeroulnar joint? Where? Reinforced by? Movements? Which processes limit movement past 180 degrees?
Trochlea of humerus and trochlear notch of ulna
Medial
Reinforced by ulnar collateral ligament
Flexion/extension
Ulnar processes
What is the humeroradial joint? Where? Reinforced by?
Capitulum of humerus, radial head
Lateral
Reinforced by radial collateral ligament
Supination/pronation
Moves passively in flexion/extension
Difference between humeroradial and humeroulnar joint?
Humeroradial joint more circular so can rotate for pronation/supination
Where do biceps brachii heads attach?
Scapula
Long vs short head of biceps brachii?
Long: attaches to tubercle superior to glenoid cavity. Runs superior to humeral head through intertubercular groove, more lateral
Short: attaches to coracoid process of scapula, more medial
Where do biceps brachii muscle bellies lie over? What ligament holds the long head in place?
Coracobrachialis/brachialis
Transverse humeral ligament
Where do both biceps brachii heads converge to?
Coverge to single tendon
Insert on radial tuberosity of radius at medial aspect of radius
What does the biceps brachii give off? What does it allow?
Gives off bicipital aponeurosis: flat sheet of connective tissue
Attaches biceps indirectly to posterior border of ulna
Biceps brachii actions?
Flexion at shoulder and elbow
Supinates radioulnar joint (fixed elbow)
Short head flexes shoulder
Long head holds humerus against glenoid cavity (stabilising function)
Biceps innervation?
Musculocutaneous nerve
Coracobrachialis attachment AND insertion?
Coracoid process - A
Medial humerus - I
Coracobrachilis actions?
Shoulder flexion
Weak adduction
Brachialis attachments?
Anterior distal humerus
Coronoid process of ulna
Brachialis action?
Flexes elbow
Coracobrachialis/brachialis innervation?
Musculocutaneous nerve
Triceps brachii attachments?
Long head: infraglenoid tubercle of scapula
Lateral head: superior, posterior humerus
Medial head: posterior humerus, distal to groove for radial nerve
Which triceps heads fuse? What do they form?
Long and lateral fuse
Deep to them is medial
Form common tendon: inserts into superior olecranon of ulna and deep fascia
Triceps actions?
Extends elbow
Long head steadies humerus
Triceps innervation?
Radial nerve
Anconeus attachments?
Lateral epicondyle of humerus
Posterior olecranon of ulna
Anconeus actions?
Elbow extension
Pronation
Tendon composition and function?
Dense, regularly arranged tissue attaching muscle to bone
Tendon composition and function?
Dense, regularly arranged tissue attaching muscle to bone
Closely packed parallel arrangement in direction of force
3 components of tendon?
tendon
bone insertion
muscle-tendon junction
Composition of tendon?
Dense connective tissue: parallel fibres of collagen
Sparsely vascularised
20% cellular = fibroblasts
80% extracellular = 70% water and 30% collagen I, ground substance, elastin, Collagen III
What is a tendinopathy?
Painful conditions arising around tendons in respinse to overuse. Complex and multifactorial
Tendinopathy risk factors?
Systemic disease e.g. diabetes/obesity
Family history
Age
Overuse
Medication - FLUROQUINOLONES, HRT
Statins
Which tendons can develop tendinopathy?
Rotator cuff tendons
Gluteal tendons
Common flexor/extensor in elbow
Patellar tendon
Achilles tendon
2 types of processes in tendon healing?
Extrinsic and instrinsic
3 phases of tendon healing and time frames?
Inflammation - 0-7 days
Repair - 3-60 days
Remodelling - 28-180 days
Which cytokines direct tendon healing?
Platelet derived growth factor: chemotaxis
Transforming growth factor b: collagen type
Where do inflammatory cells migrate from in tendon healing?
Epitendinous tissues (sheath, periosteum, soft tissues)
Epitendon and endotendon
What happens in the inflammatory phase of tendon healing?
Inflammatory cells migrate
Defect rapidly filled with granulation tissue, haematoma and tissue debris
Matrix proteins laid down as scaffolding for matrix synthesis
What happens in the repair phase of tendon healing?
Fibroblasts migrate to zone of injury and begin to synthesise collagen by day 5
Initially type III collagen produced which is laid down in a random orientation
4th week: intrinsic fibroblasts proliferate, synthesisie and reabsorb collagen = form TENDON CALLUS
Type I collagen starts being produced
Vascular ingrowth via collagen scaffolding
What happens in the remodelling phase of tendon healing?
Final stability acquired due to normal use of tendon physiologically
Cross linking of collagen fibrils increases tensile strength
Effect of early controlled mobilisation of tendon tear in rehab?
Reduce scar adhesions
Facilitate healing by stimulating remodelling
What are scar adhesions?
Dead fibrotic tissue adhering to alive tissues limiting range of movement
What happens if there is excessive loading of damaged tendon?
Disrupts repair tissue
Optimal healing of tendons requires…
Surgical apposition and mechanical stabilisation
Minimal soft tissue damage
What happens to tendon pathologically in tendonopathy
Type III collagen present instead of type I
Neovessels present
More tenoxytes present
Reasons for tendinopathy to develop>
Overuse aka mechanical stress
Drugs: fluroquinolones, statins
Genetics
Inflammation
Environmental e.g. smoking, diabetes
Apoptisis e.g. cell death
Static body components in shoulder?
Scapula: acromion, coracoid process, glenoid
Clavicle
Humerus
Capsule/ligaments
Labrum/cartilage
Dynamic body parts in shoulder?
Rotator cuff muscles
Long head of biceps
Scapular stabilisers
Test for supraspinatus function?
Flex arms at 30 degrees in front of you, then make a movement as if pouring out a can
Push down on arms, if they cant resist the force then supraspinatus tear
Test for subscapularis function?
Put hands behind back with palms facing out, if cant lift off back then subscapularis tear
Test for infraspinatus/ teres minor function?
Arms tucked in, ask to laterally rotate and push their arms, if cant do it then tear/injury
Tests for rotator cuff muscles for range of movement?
Supra = forward abduction
Infra/teres = external rotation
Subscap = thumb behind back
Test for subacromial shoulder pain?
None
Causes of rotator cuff tears?
Age >65
Tendinopathy to tear
Osteophytes
Trauma, acute
Genetic
Non operative rotator cuff tear treatment?
Phyiotherapy
Injection steroid/local for pain
Operative rotator cuff tear treatment?
Repair tendon to bone
Open surgery/arthrscopic (keyhole)
Novel rotator cuff tear treatment?
Glyceryl nitrate patches
CYtokine therapies
Arthroscopic vs open surgery?
Arthroscopic: less invasive, faster recovery, visualise whole joint
Open: more invasive, good long term results
Adult vs embro ecm to cell ratio?
Adult: 80% ECM, 20% cells
Embryo: 20% ECM, 80% cells
What is basal lamina?
Layer of extracellular matrix secreted by epithelium, where epithlium sits
How are mechanical stresses transmitted in epithelial tissue?
Transmitted from cell-cell by cytoskeletal filaments achored to cell-matrix and cell-cell adhesion sites
How is mechanical stress beared in connective tissue?
Extracellular matrix directly bears stress
Where does skeletal strength stem from?
Extracellular matrix
ECM functions?
- provides scaffold for tissue development
- provides mechanical basis for cell attachment/movement
- transmits force e.g. tendon, bone
- withstands compression in cartilage and IVD
- provides survival signalling molecules
- reservoir for growth factors
ECM composition?
50% water
proteins
glycosaminoglycans
glycoproteins
proteoglycans
Function of water in ECM?
Absorbs compressive forces
What are glycoproteins?
Proteins with carbohydrate side chains
Examples of glycoprotein side chains?
Sugars (glucose, galactose)
Amino sugars (n-acetylglucosamine)
Acidic sugars (sialic acid)
How are sugar side chains attached to glycoproteins and where?
Glycosylation in golgi by glycosyltransferase
Proteoglycan composition?
Heavily glycosylated protein with GAG side chain
Example of GAG side chain?
Chondroitin sulfate
Function of acid group in proteoglycan?
Provides negative charge that attracts water and allows protection against compressive forces
How many types of collagen are there?
30
Function of parallel collagen fibres in tendons?
Allows tension and recoil for functional ability
Composition of collagen in skin and cornea?
Skin: criss cross
Cornea: running in different directions
What is fibrosis?
Uncontrolled deposition of collagen
Functions of collagen? Different ways they form?
Fibril forming: tensile strength e.g. bone, cartilage
Endostatin-producing: cell migration/signalling regulation
Anchoring fibrils: cell to matrix interactions
Transmembrane: cell to matrix interactions
Bead forming: elasticity
What is a rare disease defined as?
1 in 10k people have it