Elbow & wrist Flashcards
Muscles involved in extension of the elbow
Triceps brachii and anconeus
Muscles involved in flexion
Brachialis, biceps brachii, brachioradialis
What is a bursa? What is its function?
A bursa (plural bursae) is simply a membranous sac, filled with synovial fluid. It acts to cushion the moving parts of a joint, preventing degenerative damage.
Outline the stability of the elbow joint inc. joint type & ligaments
- Like all synovial joints, the elbow joint has a fibrous capsule enclosing the joint.
- The joint capsule is thickened medially and laterally to form collateral ligaments, which stablise the flexing and extending motion of the arm.
- The radial collateral ligament is found on the lateral side of the joint, extending from the lateral epicondyle, and blending with the anular ligament of the radius (a ligament from the proximal radioulnar joint).
- The ulnar collateral ligament originates from the medial epicondyle, and attaches to the coronoid process and olecrannon of the ulna.
- Anular ligament (blends with radial collateral)
- Shape of the bones - the humerus and ulna interlock
Name and describe three bursae of the elbow
Intratendinosus: Formed within the tendon of the triceps brachii.
Subtendinosus: Found between the olecrannon and the tendon of the triceps brachii, reducing friction between the two structures during extension and flexion of the arm.
Subcutaneous: Found between the olecrannon and the overlying connective tissue.
Why are bursae clinically important?
Can become irritated and inflamed, producing pain.
What blood vessels supply the wrist?
The wrist joint receives blood from branches of the dorsal and palmar carpal arches, which are derived from the ulnar and radial arteries
Name the articulating surfaces of the wrist
o Distally – The proximal row of the carpal bones (except the pisiform).
o Proximally – The distal end of the radius, and the articular disk (see below).
The ulna is not part of the wrist joint – it articulates with the radius, just proximal to the wrist joint, at the distal radioulnar joint. It is prevented from articulating with the carpal bones by a fibrocartilginous ligament, called the articular disk, which lies over the superior surface of the ulna.
Name three nerves that innervate the wrist
Median nerve – Anterior interosseous branch.
Radial nerve – Posterior interosseous branch.
Ulnar nerve – deep and dorsal branches.
Stability of the wrist is due to its (synovial) joint capsule and ligaments. Name the ligaments of the wrist and where they are found
Palmar radiocarpal - It is found on the palmar (anterior) side of the hand. It passes from the radius to both rows of carpal bones. Its function, apart from increasing stability, is to ensure that the hand follows the forearm during supination.
Dorsal radiocarpal - It is found on the dorsum (posterior) side of the hand. It passes from the radius to both rows of carpal bones. It contributes to the stability of the wrist, but also ensures that the hand follows the forearm during pronation.
Ulnar collateral - Runs from the ulnar styloid process to the triquetrum and pisiform. Works in union with the other collateral ligament to prevent excessive lateral joint displacement.
Radial collateral - Runs from the radial styloid process to the scaphoid and trapezium. Works in union with the other collateral ligament to prevent excessive lateral joint displacement.
The wrist is what kind of joint? What movements does this allow for?
Ellipsoid type synovial joint, allowing for movement along two axes. This means that flexion, extension, adduction and abduction can all occur at the wrist joint.
Boundaries of the anatomical snuff box
Ulnar (medial) border: Tendon of the extensor pollicis longus.
Radial (lateral) border: Tendons of the abductor pollicis longus and extensor pollicis brevis.
Proximal border: Styloid process of the radius.
Floor: Carpal bones; scaphoid and trapezium.
Roof: Skin.
What’s the other name for the wrist? what kind of joint is it
Radiocarpal joint - condyloid type synovial joint
& midcarpal joint
What tissue lies between the ulna and radius
interosseus membrane
How many radio-ulnar joints are there?
two - one distal, one proximal
What is the most proximal end of the ulnar and what attaches here?
Olecranon - triceps tendon
What is the prominence opposite the olecranon of the ulna?
Coronoid process
Where does the brachioradialis tendon insert?
Lateral part of styloid process of the radius
Where does the radius articulate with the ulnar?
Radial notch
Where does the head of the radius articulate with?
Capitulum of the humerus
What inserts on the radial tuberosity?
Biceps tendon
Why are the elbow and proximal radioulnar joint considered to be one joint?
They are enclosed within one continuous space
Unlike the wrist and distal radioulnar joint - which are physically separate
What bony features are at the distal end of the ulnar?
Head and ulnar styloid process
What bony features are at the distal end of the radius?
Radial styloid process & ulnar notch
How many distal articulating surfaces does the radius have?
Two - one with the ulnar, one with the proximal metacarpal bones
Name the two pronator muscles of the foream and two supinator muscles
Which action is more powerful and why?
Pronator teres & pronator quadratus
Supinator & biceps brachii
Which action is more powerful; supination or pronation and why?
Supination - because of the powerful action biceps provides
Name the wrist flexors
Flexor carpi radialis, flexor carpi ulnaris, palmaris longus
Name the wrist extensors
Extensor carpi radialis longus & brevis, extensor carpi ulnaris
What do the wrist extensors pass under? What action does this tissue have?
Extensor retinaculum acts as a pulley
What veins drain from the upper limb
Basilic & cephalic –> brachial veins (two) –> brachial vein –> axillary vein
What is the name of the vein that joins the basilic and cephalic vein anterior to the elbow?
Antecubital vein
Describe the arterial blood supply to the upper limb
Subclavian artery - axillary - brachial artery [- deep brachial (profunda brachii)] - ulnar & radial arteries
Which nerve runs closely to the brachial artery and passes over it?
Median nerve
What does the radial nerve branch into?
In the forearm the radial nerve divides into a deep (motor) branch and a superficial (Sensory) branch
Describe the two articulating surfaces of the elbow?
Trochlear notch of the ulna and the trochlea of the humerus
Head of the radius and the capitulum of the humerus
(nb: The proximal radioulnar joint is found within same joint capsule of the elbow, but most literature considers it as a separate articulation)
