Movement lecture 3: Upper limb - elbow Flashcards
Which 2 articulations make up the elbow joint?
Humero-ulnar - between trochlea of the humerus and trochlear notch of the ulna.
Humero-radial - between capitulum and upper surface of radial head
Which ligaments reinforce the elbow joint?
Reinforced laterally by the radial collateral ligament
Reinforced medially by the ulnar collateral ligament
Why is the elbow joint capsule not reiforced posteriorly or anteriorly?
To allow for flexion and extension.
Why is the elbow joint one of the most stable joints in the body?
The good ‘fit’ (congruity) between the trochlear notch of the ulna and trochlea of the humerus.
What are the features of posterior elbow dislocation?
The distal end of humerus is driven through the weak anterior part of the joint capsule
Causes:
Fall onto hands with elbows flexed
Hyperextension (blow that drives ulna posteriorly or posterolateral)
What findings are sometimes associated with elbow dislocation?
Associated findings:
Ulnar collateral ligament torn
Fractures- head of radius, coronoid process, olecranon process
Ulnar nerve injury
What are the consequences of ulnar nerve injury?
Numbness of medial part of palm and medial one and a half fingers
AND weakness of flexion and adduction of the wrist
What are the features of a simple elbow dislocation?
No fracture of the bones around the elbow joint: normally ligamentous injury
Good prognosis as often surgery is not required for treatment
What are the features of complex elbow dislocation?
Associated with fracture, usually of the forearm.
Surgery is often needed to fix the broken bone in order to maintain the elbow joint in a normal position
What normally limits the extension of the elbow?
The olecranon process of the ulna fitting into the olecranon fossa.
What abornomality allows for hyperextension of the elbow joint?
The presence of an olecranon foramen instead of an olecranon fossa.
What are the three flexors acting at the elbow joint?
Biceps brachii, brachialis and brachioradialis
What is the primary flexor of the elbow?
Brachialis
What is the function of brachioradialis?
An accessory flexor of elbow joint when forearm is mid-pronated.
What is the name of the 1 extensor of the elbow?
Triceps brachii
What are the origins of triceps brachii?
Long head - Infraglenoid tubercle (scapula)
Lateral head - Posterolateral humerus above spiral groove
Medial head - Posteromedial humerus below spiral groove
What is the insertion of triceps brachii?
Olecranon process
What is the innervation of triceps brachii?
Radial nerve C5-T1
What is the olecranon bursa?
Bursa that protects the olecranon process of the elbow.
What is often the cause of olecranon bursitis?
Excessive, repeated pressure and friction over the olecranon can cause inflammation of the bursa
This causes swelling of the bursa which may be visible and is painful on palpation
What is the name of the other joint that lies within the elbow capsule?
The proximal radioulnar joint
What is the proximal radioulnar joint?
This is an articulation between the head of the radius and the radial notch of the ulna
What is the function of the proximal radioulnar joint along with the annular ligament?
Maintains stability of radius
Allows rotation of the radius during pronation and supination of the forearm.
What are the pronator muscles of the elbow?
Pronator teres and quadratus.
What are the supinators of the elbow?
Supinator and biceps brachii
What is the primary function of biceps brachii?
Supination of the forearm.
What are the two common sites of epicondylitis?
Insertions of the wrist extensor tendons into the lateral epicondyle (‘tennis elbow’).
Insertions of wrist flexor tendons into the medial epicondyle (‘golfer’s elbow’)
What is avulsion of the medial epicondyle?
Medial epicondyle ossifies separately from the rest of the humerus and is only connected by cartilage until 14-20 years when fusion occurs
Before fusion, severe trauma causing abduction of the elbow stretches the ulnar collateral ligament which can pull the medial epicondyle out of position
Risk of stretching the ulnar nerve
What kind of nerve injury is associated with fracture of the surgical neck of the humerus?
Axillary nerve injury – test deltoid function and sensation in regimental badge area
Which nerve may be injured by a humeral shaft fracture?
Radial nerve
Which nerve may be injured by a supracondylar fracture?
Median nerve
