IFS Unit 6 Elbow

What are the 3 bones of the elbow joint?

Radius, ulna, humerus

What are the 2 articulations of the elbow joint?

Humeral-ulnar and humeral-radial articulation

What articulates with the radial notch?

Capitulum

What articulates with the trochlea?

The head of the ulna

What lines the capitulum and trochlea?

Hyaline cartilage

What is the attachment site for flexors?

Medial epicondyle

Where does the ulnar nerve run?

behind the medial epicondyle

Where does the ulna articulate when the elbow is fully flexed?

Coronoid fossa

Where does the ulna articulate when the elbow is fully extended?

Olecranon fossa

What is found proximal to the humeral condyles and serve as attachment sites for muscles of the arm and forearm?

Medial and lateral supracondylar ridges

What is the most stable elbow joint and why?

Humeral-ulnar because the ulna locks in to the humeral trochlea

What normally limits elbow flexion?

Approximation of the anterior arm and forearm soft tissue

What limits elbow flexion?

the olecranon fossa

When the elbow moves into flexion, what occurs in relation to the forearm and arm?

They become approximated

When the elbow moves into extension, what occurs in relation to the forearm and arm?

The forearm moves away from the arm

Why do the elbow joint have a small obliquity and what is this called?

Because the humeral trochlea is longer medially relative to the capitulum which is called the carrying angle

What is the purpose of the carrying angle?

It serves the purpose of clearing the swinging arm away from the pelvis when walking, especially when carrying objects

Do males or females have a larger carrying angle?

Females

What joint is the proximal radio-ulnar joint related to?

The elbow joint

What joint is the distal radio-ulnar joint related to?

Wrist joint

What is the purpose of the radio and ulnar styloid processes?

Attachment for ligaments of the wrist

What is the function of the interosseous membrane?

Hold the radius and ulna together

What occurs in the forearm when it pronates?

The radius rotates medially so that the palm of the hand is facing posteriorly and the carrying angle disappears

What occurs in the forearm when it supinates?

Lateral rotation of the radius and it crosses over the ulna

What kind of joint is the elbow?

A modified hinge joint

What is the joint capsule?

Fibrous layer and synovial membrane that lines the non-articular parts of the joint with fluid on the inside

What is the function of the ulnar (lateral) collateral ligament?

Serves as the primary restraint against varus forces at the elbow

What are varus forces?

A force that pushes the forearm medially and create a medial angulation or adduction of the elbow joint

What are the 3 parts of the ulnar collateral ligament?

Anterior, posterior, oblique

What is the strongest band of the ulnar collateral ligament?

Anterior band

Which band of the ulnar collateral ligament only has attachment to the ulna and does not serve as a primary restraint to elbow motions?

Oblique band

What is the role of the oblique band of the ulnar collateral ligament?

To stabilize radius to ulna

What kind of forces is the elbow more frequently subjected to?

Valgus forces

What kind of angulation is created by valgus forces?

Lateral angulation to the joint

What is the role of the Pronator Teres?

Pronates and assist in elbow flexion

What ligament crosses the proximal radioulnar joint and the humeral ulnar joint?

Pronator Teres

What is the function of the Pronator quadratus?

pronates forearm

The distal radioulnar joint has a fibrous layer that encloses the joint and a synovial layer that forms what is called a

Sacciform recess

What is the function of the sacciform recess?

It accommodates the twisting of the capsule during pronation and supination of the forearm and holds the synovial fluid

What connects the distal end of the radius and ulna?

An articular disc called the triangular fibrocartilage

Where does the triangular fibrocartilage attach?

It attaches to the ulnar notch of the radius and to the lateral aspect of the styloid process and the capsular ligament of the distal radio-ulnar joint

What is the function of the triangular fibrocartilage?

It plays an important role in joint stability by maintaining approximation of the distal radius and ulna

What structures limit supination?

Triangular fibrocartilage, interosseous membrane, palmar capsular ligament at the distal radio-unlearn joint

What structures limit pronation?

Triangular fibrocartilage, dorsal capsular ligament at the distal radio-ulnar joint

Where does reinforcement of the distal radius and ulna come from?

The palmar and dorsal capsular ligament

What are the primary stabilizers of the distal radio-ulnar joint?

Articular disc, palmar, and dorsal capsular ligaments and the ulnar collateral ligaments

What are the primary flexors of the elbow?

Biceps brachii and brachialis

What is a fusiform muscle that acts on the GH, humeral ulnar and radial ulnar joints?

Biceps brachii

What are the attachments of the biceps long head?

Supraglenoid tubercle to the radial tuberosity

What are the attachments of the biceps short head?

Coracoid process to radial tuberosity

When does the bicep brachii demonstrate increased activity?

When the elbow is flexed and accompanied by supination of the forearm

What kind of muscle is the brachialis?

Fusiform

What is the longest of the elbow flexors and demonstrates greatest EMG activity through fast movements of elbow flexion and can assist in pronation and supination?

Brachioradialis

What are the primary elbow extensors?

Triceps and anconeus muscles

What muscle has proximal attachments to the posterior humerus and acts on the elbow joint?

Triceps

What muscle runs from the lateral epicondyle of the humerus to the lateral border of the olecranon and the posterior aspect of the proximal ulna?

Anconeus

What muscle is better for stabilizing elbow and preventing pitching of the joint capsule because it attaches into the elbow joint capsule?

Anconeus

What are the primary pronators of the forearm?

pronator teres, pronator quadratus

What kind of muscle is the Pronator Teres?

Fusiform muscle with two heads

What are the attachments of the Pronator Teres?

Medial epicondyle of the humerus, proximal ulna, and lateral radius

What is the orientation of the palm if the forearm in is supinated and the elbow is flexed?

Superiorly

What is the orientation of the palm if the forearm in is supinated and the elbow is extended?

Anteriorly

When will the activity of the Pronator Teres increase?

As the power demand of the activity increases

What are the primary supinators?

Supinator muscle and the biceps brachii

What are the secondary supinators of the forearm?

Extensor pollicis longus and extensor digitis

What muscle attaches to the lateral epicondyle of the humerus and wraps around the proximal third of the radius to become part of the floor of the cubical fossa?

Supinator muscle

What is recruited with more forceful supination and when the elbow is in a more flexed position like tightening a screw?

Biceps brachii

What is the triangular depression in the anterior elbow known as?

Cubital fossa

What is the lateral boundary of the cubital fossa?

Brachialis muscle

What is the medial boundary of the cubital fossa?

pronator teres

What is the superior boundary of the cubital fossa?

imaginary line between medial and lateral epicondyles of humerus

What muscles are innervated by the radial nerve?

Brachioradialis, triceps brachii, anconeus, supinator

What muscles are innervated by the median nerve?

Pronator teres, Pronator quadratus, Pronator teres

What muscles are innervated by the musculocutaneous nerve?

brachialis, biceps brachii, coracobrachialis

Where do all flexors converge?

Medial epicondyle

Where do all the extensors converge?

Lateral epicondyles

What encloses the anterior and posterior compartment to the arm?

Brachial fascia

Where does the musculocutaneous nerve arise from?

Anterior rami of C5 to C7

What nerve arises from the anterior rami of C5 to C8 and continues to the arm via the medial and lateral cord to the brachial plexus?

Median nerve

What is the largest branch of the median nerve that innervates the muscles of the deep flexor compartment and runs along the interosseous membrane to innervate the quadratus muscle?

Anterior interosseous nerve

Does the radial nerve innervate any of the muscles of the hand?

No it only gets the skin in the back of the hand

What nerve arises from C5 to T1 anterior rami and enters the arm as a branch of the posterior cord?

radial nerve

What nerve arises from the anterior rami of C8 and T1 and enters the arm as the terminal branch of the medial cord?

ulnar nerve

What law states the nerve supplying the joint also supply the muscles moving the joint and the skin covering their distal attachments?

Hilton Law

What are the lateral arm and proximal forearm are innervated by what nerve?

C5 spinal segment

What nerve supplies the medial forearm and arm?

C8 and T1

What is the nerve that innervates the muscle produce flexion at the elbow?

C5 and C6

What is the nerve that innervates the muscle that produce flexion at the elbow?

C6 and C7

What spinal nerve innervates the supinators?

C6

What spinal nerve innervates the pronators?

C7 and C8

What is the continuation of the axillary artery and begins inferior to the teres major muscle?

brachial artery

What are the branches of the brachial artery?

profunda brachii artery, superior ulnar collateral artery, inferior ulnar collateral artery

The brachial artery courses anterior to the trochelea of the humerus and divides into what arteries?

radial and ulnar arteries

Where is the cephalic vein located?

thumb side (lateral)

Where is the basilic vein located?

pinky side (medial)

What is elbow valgus limited by?

contact of capitulum and radius

What is elbow varus limited by?

contact of ulna and trochlea

What direction is the roll and glide of the humeral-ulnar joint?

roll and glide in the same direction (concave on convex)

What is responsible for transmitting weight bearing forces from distal radius to proximal ulna?

interosseous membrane

What bone of the elbow joint takes 80% of the weight?

radius