Chapter 6 - The Elbow and Radioulnar Joints Flashcards
Is the elbow different than the radioulnar?
Yes
Proximal v. Distal Anatomy
- Ulna –> proximal bigger
- Radius –> radius bigger
What type of joint is it?
A lot of motion, diarthrodial –> hinge –> ginglymus
2 interrelated joints
- Where does the motion mainly occur?
- Majority of motion occurs at humeroulnar joint and to a lesser degree at radiohumeral
What is the UCL and what does it do?
- Ulnar collateral ligament
- Resist valgus stress (stress on lateral side of joint)
- 3 bands: anterior band; helps resist valgus stress most (injured most often)
What is the RCL?
- Humerus to radius on lateral side
- Resist a varus stress (stress on medially side)
What is the annular?
- Acts as a sling to hold radial head against the ulna
Radiolulnar joint
- Type?
- Diarthrodial –> pivot –> trochoid
- Radial head rotates around the proximal ulna
- Distal radius rotates around the distal ulna
- Held together by interosseus memnrane
Movements?
- Flexion: move our hand toward our shoulder
- Extension: move our hand away from our shoulder
- Pronation: palm down
- Supination: palm up
Muscles
- Flexors?
- Extensors?
- Radioulnar Pronators?
- Radioulnar Supinators?
Flexors: - Biceps brachii - Brachialis - Brachioradialis Extensors: - Triceps - Anconeoneus Pronators: - Pronator quatratis - Pronator teres - Brachioradialis Supinators: - Biceps Brachialis - Supinator - Brachioradialis
What are some common injuries and how do they occur?
Tennis Elbow:
- Lateral epicondylitis, extension of the wrist paired with supination. Backhand tennis shots
Golfer’s Elbow:
- Medial epicondylitis, flexion and pronation
What does the radial nerve innervate and where does it originate?
- Originates from C5-C8, innervates triceps, brachioradialis, supinator, anconeus
What does the median nerve innervate and where does it originate?
- Derived from C6 and C7, innervates pronator teres, pronator quadratis
What does the musculotaneous nerve innervate and where does it originate?
- Branches from C5 and C6, innervates biceps brachii and brachialis
Biceps Brachii Muscle
- Origin?
- Insertion?
- Movements?
Origin: - Coracoid process Insertion: - Radial tuberosity Movements: - Flexion of elbow - Supination of forearm - Weak flexion of shoulder joint - Weak abduction of shoulder joint when externally rotated
Brachialis Muscle
- Origin?
- Insertion?
- Movements?
Origin: - Distal half of anterior portion of humerus Insertion: - Coronoid process of ulna Movements: - True flexion of elbow
Brachioradialis Muscle
- Origin?
- Insertion?
- Movements?
Origin:
- Distal 2/3 of lateral condyloid ridge of humerus
Insertion:
- Lateral surface of distal end of radius at styloid process
Movements:
- Flexion of elbow
- Pronation from supinated position to neutral
- Supination from pronated position to neutral
Triceps Muscle
- Origin?
- Insertion?
- Movements?
Origin:
- Long Head: infraglenoid tubercle of scapula
- Lateral Head: upper half of posterior surface of the humerus
- Medial Head: distal 2/3 of posterior surface of humerus
Insertion:
- Olecranon process of ulna
Movements:
- All heads: extension of elbow
- Long head: extension of shoulder joint; adduction of shoulder joint; horizontal abduction
Anconeus Muscle
- Origin?
- Insertion?
- Movements?
Origin:
- Posterior surface of lateral condyle of the humerus
Insertion:
- Posterior surface of upper ulna and olecranon
Movements:
- Extension of elbow
Pronator Teres Muscle
- Origin?
- Insertion?
- Movements?
Origin:
- Distal part of medial condyloid ridge of humerus, medial side of the proximal ulna
Insertion:
- Middle third of lateral surface of radius
Movements:
- Pronation of forearm
- Weak flexion of elbow
Pronator Quadratus Muscle
- Origin?
- Insertion?
- Movements?
Origin: - Distal fourth of anterior side of ulna Insertion: - Distal fourth of anterior side of radius Movements: - Pronation of forearm
Supinator Muscle
- Origin?
- Insertion?
- Movements?
Origin:
- Lateral epicondyle of humerus and neighboring posterior part of ulna
Insertion:
- Lateral surface of proximal radius just below head
Movements:
- Supination of forearm
Elbow Flexion
- Muscles?
- Biceps Brachii (long head)
- Biceps Brachii (short head)
- Brachialis
- Brachioradialis
- Pronator Teres (Weak Flexion)
Elbow Extension
- Muscles?
- Triceps Brachii (long head)
- Triceps Brachii (lateral head)
- Triceps Brachii (medial head)
- Anconeus
Radioulnar Pronation
- Muscles?
- Pronator Teres
- Pronator Quadratus
Radioulnar Supination
- Muscles?
- Biceps Brachii (long head)
- Biceps Brachii (short head)
- Supinator
