Chapter 6 The Elbow and Radioulnar Joints

elbow actions

Flexion: zero to 150 degrees Extension: 150 degrees to zero Hyperextension: measured in degrees beyond the zero starting point This motion is not present in all persons When it is present, it may vary from 5 to 15 degrees

What are the bones that make up the elbow/radioulnar joints?

Humeru, Ulna, Radius, Scapula

Radioulnar Pronation

Agonists •Pronator teres •Pronator quadratus •Brachioradialis

What action does the Triceps brachii do?

All Heads - Extension of elbow Lateral Head - Extension of shoulder joint, adduction of shoulder joint, horizontal abduction

What is the carrying angle and its normative values?

The angle formed between the humerus and the forearm deviating laterally between 5 to 15 degrees Males - 5 degrees Females - 10-15 degrees

Supinator Muscle

supination of forearm

What is the surgical procedure for UCL injury?

Tommy John surgery using a tendon graft such as the palmaris longus.

What is a gunstock deformity? what usually causes it to form?

Very rare Varus deformity that is caused by a proximal radial fracture.

What action does the Pronator teres do?

Weak Flexion of elbow, pronation of forearm

Varus (Gunstock) Deformity

•Much more rare • •Usually result of proximal radius fracture

Ulnar collateral ligament or U C L

•Particularly crucial to high-velocity sporting activities, such as baseball pitching, that require optimal medial elbow stability •Compromise of this structure often requires surgery •Pitching Elbow

Posterior

•Primarily extension and supination •Triceps brachii •Anconeus •Supinator

Anterior

•Primarily flexion and pronation •Biceps brachii •Brachialis •Brachioradialis •Pronator teres •Pronator quadratus

Elbow motions

•Primarily involve movement between articular surfaces of the humerus and ulna •Specifically the humeral trochlear fitting into the ulna trochlear notch

Medial epicondylitis (golfer's elbow)

•Somewhat less common •Associated with the medial wrist flexor and the pronator group near their origin on the medial epicondyle •Both conditions involve muscles that cross the elbow but act primarily on the wrist and hand

Radioulnar joint

•Trochoid or pivot-type joint •Radial head rotates around at the proximal ulna •Distal radius rotates around the distal ulna •Annular ligament maintains the radial head in its joint

Tommy John Surgery

•UCL surgical reconstruction using a tendon graft such as the palmaris longus tendon •Only 85% of people have a palmaris longus tendon •Can also use plantaris, gracillis, or semiT tendon if PL is not available •Recovery time ≥ 1 year

ulna vs radius

•Ulna is much larger proximally than in radius •Radius is much larger distally than the ulna •Scapula and humerus serve as proximal attachments for muscles that flex and extend the elbow

Brachioradialis Muscle (drinking muscle)

flexion of elbow, pronation from supinated position to neutral, supination from pronated position to neutral

Biceps Brachii Muscle

flexion of elbow, supination of forearm, weak flexion of shoulder joint, weak abduction of shoulder joint when externally rotated

Distally, the radius is ______ than the ulna.

larger

Proximally, the ulna is ______ than the radius.

larger

•Many contact sports and throwing activities place stress on ______ _______ of the joint, resulting in injury

medial aspects

•Ulnar collateral ligament is critical in providing ...

medial support to prevent the elbow from abducting when stressed during physical activity

As the elbow reaches full extension, the olecranon process is received by the _________ _____.

olecranon fossa

Pronator Quadratus Muscle

pronation of forearm

Pronator Teres Muscle

pronation of forearm, weak flexion of elbow

•Scapula and humerus serve as ________ attachments for muscles that flex and extend the elbow.

proximal attachments for muscles that flex and extend the elbow

what action does the biceps brachiallis do?

True Flexion of elbow

UCL Prehab

1•Increasing power in lower extremity musculature (•Olympic Lifts) 2•Adequate scapular stability (•Establish a stable base for which shoulder to move through) 3•Sufficient shoulder mobility (•External Rotation) 4•Stability of elbow joint in frontal plane (•"Feed the mistake") 5•Sufficient wrist mobility (•Wrist extension)

What are the muscles of the elbow/radioulnar joints?

Biceps Brachii, Biceps Brachialis, Biceps Brachioradialis, pronator teres, pronator quadratus, triceps brachii, anconeus, supinator.

Tennis elbow

Common problem usually involving the extensor digitorum muscle near its origin on the lateral epicondyle •Known as the lateral epicondylitis or depending upon specific pathology may be termed lateral epicondylagia or lateral epicondylosis •Associated with gripping and lifting activities

•Ulna and radius serve as ______ attachments for the same muscles

Distal

What is the most common way elbow dislocation happens?

Due to bony geometry, elbow dislocation generally involves movement of the humerus anteriorly, hyper-extension injury

Elbow Flexion

Example: Biceps curl Agonists •Biceps brachii •Brachialis •Brachioradialis

Elbow Extension

Example: Push-up •Agonists •Triceps brachii •Anconeus

Radioulnar Supination

Example: Tightening ascrew Agonists •Biceps brachii •Supinator muscle •Brachioradialis

What action does the Anconeus do?

Extension of elbow

What action does the brachioradialis do?

Flexion of elbow, pronation from supinated to neutral, supination from pronated to neutral

What action does the biceps brachii do?

Flexion of elbow, supination of forearm, weak flexion of shoulder joint, weak abduction of shoulder joint when externally rotated.

Elbow Joint type and actions

Ginglymus or hinge-type joint •Allows only flexion and extension

What action does the pronator quadratos do?

Pronation of forearm

Radioulnar Joint Actions

Pronation: zero to 80 or 90 degrees Supination: zero to 80 or 90 degrees Total forearm motion: 160 to 180 degrees Persons may vary in the range of supination and pronation Some may reach the 90-degree arc, and others may have only 70 degrees plus

•Scapula, humerus, and ulna serve as _________ attachments for muscles that pronate and supinate the radioulnar joints

Proximal

•Distal attachments of radioulnar joint muscles are located on the ______.

Radius

What action does the Supinator muscle do?

Supination of forearm

What are the injuries at the elbow joint?

Tennis elbow (lateral epicondylitis)- Common problem. Involves the extensor digitorum muscle near its origin on the lateral epicondyle. Associated with lifting/gripping. Known as lateral epicondylitis, epicondylagia or lateral epicondylosis Golfer's elbow (Medial epicondylitis) - Less Common. Involves medial wrist flexor and the pronator group near their origin on the medial epicondyle. Associated with muscles that cross the elbow but act primarily on the wrist and hand

What position is the elbow most stable?

The elbow is most stable when fully extended due to increased joint stability.

Annular ligament provides

a sling effect around the radial head for stability

Triceps brachii muscle

all heads: extension of elbow long head: extension of shoulder joint; adduction of shoulder joint; horizontal abduction

What are the anterior muscles?

biceps brachii, brachialis, brachioradialis, pronator teres, pronator quadratus

Radial head has a relatively small amount of contact with the

capitulum of the humerus

•With the elbow in full flexion, the coranoid process fits into the ________ _____

coranoid fossa

The Elbow has increased joint stability when fully ________.

extended

Anconeus Muscle

extension of elbow

How do most UCL injuries occur?:

high-velocity throwing activities, such as baseball pitching cause UCL injuries.

•Due to bony geometry, elbow dislocation generally involves movement of the ...

humerus anteriorly. •Hyper extension injury

Radial collateral ligament provides

lateral stability & is rarely injured

Stability in flexion is more dependent on

lateral/radial collateral ligament and the medial/ulnar collateral ligament

What are the posterior muscles?

triceps brachii, anconeus, supinator

Brachialis Muscle

true flexion of elbow

As the elbow flexes 20 degrees or more, its bony stability is ...

unlocked, allowing for more side-to-side laxity

Flexion

•Movement of the forearm to the shoulder by bending the elbow to decrease its angle

Supination

•External rotary movement of the radius on the ulna that results in the hand moving from a palm-down to a palm-up position

Interrelated joints of elbow

•Humeroulnar joint •Radiohumeral joint

Carrying angle of the elbow

•In the anatomical position, it is common for the forearm to deviate laterally from the arm between 5 to 15 degrees •10-15 degrees in females •5 degrees in males • •Slightly greater in a dominant limb than in a nondominant limb

Pronation

•Internal rotary movement of the radius on the ulna that results in the hand moving from a palm-up to a palm-down position

Elbow Bony Landmarks

•Medial condyloid ridge •Olecranon process •Coranoid process •Radial tuberosity

Key bony landmarks for wrist & hand muscles

•Medial epicondyle •Lateral epicondyle •Lateral supracondylar ridge

The Elbow and Radioulnar Joints

•Most upper extremity movements involve the elbow and radioulnar joints •Usually grouped together owing to their close anatomical relationship •Elbow joint movements may be clearly distinguished from those of the radioulnar joints •Radioulnar joint movements may be distinguished from the wrist

Extension

•Movement of the forearm away from the shoulder by straightening the elbow to increase its angle