The Elbow Chane Price PGY-3 Anthony Esposito PGY-4

Course Objectives Review function and anatomy of the elbow Brief discussion on U/S techniques for the elbow Brief discussion of potential pathology of elbow Hands on Ultrasound

Elbow Anatomy The elbow is a simple, hinge joint that allows flexion, extension, supination, and pronation of the arm. The joint is comprised of: 3 bones (humerus, ulna, and radius) 3 articulations (trochlea of humerus with the ulna, capitulum of the humerus with the head of the radius, and pivot-joint between the head of the radius and the radial notch of the ulna) 3 Ligaments (ulnar & radial collateral ligaments, annular ligament) Several muscles that cross the elbow Nerves , Veins, Arteries

Muscles of Elbow Biceps Brachii: O-Coracoid process and Supragleniod tubercle, I- radial tuberosity. A: flexion and supination. Triceps Brachii: O- Scapula and back surface of the Humerus , I- Olecranon process. A: main extensor of the elbow. Brachialis: O- lower half of the front of the Humerus, I- coronoid process. A: strongest elbow flexor when palm is pronated. Brachioradialis: O- outer edge of the lower third of the Humerus, I: lower end of the Radius. A: elbow flexion and aid pronation and supination. Pronator Teres: O- above medial epicondyle, I- outer surface of Radius. A: aid flexion of elbow and pronate the forearm. Extensor Carpi Radialis Brevis: O- lateral epicondyle of the humerus, I- third metacarpal of hand. A: extend wrist and aid extension of elbow. Anconeus: O- posterior surface of lateral epicondyle, I- on ulna lateral to the olecranon. A- controversial, assists in extension of elbow.

Elbow Articulations

Main Ligaments of Elbow

Ligamentous Functions Ulnar Collateral Ligament: extends from medial epicondyle of the humerus to the proximal portion of the ulna. Prevents excessive abduction of the elbow joint Radial Collateral Ligament: extends from lateral epicondyle of the humerus to the head of the radius. Prevents excessive adduction of the elbow joint. Annular Ligament: encircles the head of the radius, and retains it in contact with the radial notch of the ulna

Elbow Flexors Biceps Brachii Brachialis Brachioradialis Pronator Teres

Elbow Extensors Triceps Brachii Extensor Carpi Radialis Brevis Anconeus

Biceps Brachii Origin: Coracoid process and Supraglenoid Tubercle Insertion: radial tuberosity Action: flexion and supination of elbow

Biceps Tendon

Brachialis Origin- lower half of the front of the humerus Insertion- coronoid process. Action: strongest elbow flexor when palm is pronated.

Anterior Joint Recess

Radial Nerve and PIN

Radial Tunnel Syndrome Compression of PIN Refractory lateral elbow and forearm pain Radial tunnel runs from radiocapitellar joint to distal edge of supinator. Bordered medially by brachialis muscle and biceps tendon distally. Lateral border is comprised of ECRL and ECRB Anterior view of the course of the radial nerve. Note the position of the deep branch of the radial nerve (posterior interosseous nerve) as it passes through the arcade of Frohse at the proximal margin of the superficial head of the supinator muscle.

Radial Tunnel Syndrome C. Short axis sonogram of the right posterior interosseous nerve (arrow) just proximal to the supinator muscle (S) demonstrates swelling, with short axis dimension 2mm. R = radius. D. Short axis sonogram of the left posterior interosseous nmuscle (S) performed for comparison demonstrates normal caliber of the nerve, with erve (arrow) just proximal to the supinator short axis dimension 1mm. R = radius.

ECRB Origin- lateral epicondyle of the Humerus, Insertion- third metacarpal of hand. Action- extend wrist and aid extension of elbow.

Lateral Elbow: common extensor tendon

Lateral Epicondylitis “Tennis Elbow” Common Extensor Tendon (ECRB) Overuse injury Lateral epicondylitis with thick hypoechoic tendon insertion on the left compared to normal longitudinal plane on the right.

Mark the lateral epicondyle and radial head Place the patient in a comfortable, supine position. This aids relaxation and guards against possible fainting.[1] Have the patient flex the affected elbow to 90° with the hand tucked under the buttock. Mark the lateral epicondyle and radial head Inject the corticosteroid and local anesthetic into the common extensor tendon origin at the lateral humeral epicondyle. Infiltrate the corticosteroid deeply at the tenoperiosteal junction. A painful reaction to injection or firm resistance during injection suggests that the needle is too deep and is within the body of the tendon; withdraw the needle 1/8 inch if this occurs. The needle should move freely with skin traction if the tip is above the tendon; conversely, the needle sticks in place if the tip is within the body of the tendon. Inject the corticosteroid at the tissue plane between the subcutaneous fat and the tendon. 20

Common Flexor Tendon Pronator Teres Flexor Carpi Radialis Palmaris Longus Flexor Digitorum Superficialis Flexor Carpi Ulnaris

Ulnar Collateral Ligament extends from medial epicondyle of the humerus to the proximal portion of the ulna. Prevents excessive abduction of the elbow joint composed of three bands: anterior, posterior, and transverse bands.

Medial Elbow: Common Flexor Tendon and Ulnar Collateral Ligament

Medial Epicondylitis Medial epicondylitis with a thickened hypoechoic common flexor tendon insertion and intratendinous rupture Normal tendon longitudinal

Triceps Origin- Scapula and back surface of the humerus Insertion- Olecranon process Action: main extensor of the elbow

Posterior Elbow: Triceps tendon

Triceps Tendonitis/Rupture Most commonly occurs due to repetitive activities placing strain on the triceps tendon such as pushing activities or straightening the elbow against resistance (Weight lifting). May occur suddenly due to a high force going through the triceps tendon beyond what it can withstand (Fist pump).

Triceps Tendonitis/Rupture Old triceps rupture with extensive calcifications Intact tendon longitudinal

Cubital Tunnel/Ulnar Nerve

Ulnar Nerve Compression “Cubital Tunnel Syndrome” Causes: ulnar nerve instability, direct pressure, trauma second most common focal peripheral neuropathy

Ulnar Nerve Compression Symptomatic focal enlargement of the ulnar nerve (large arrows) compared with the more normal caliber nerve (small arrows) in the longitudinal plane. If there is compression, the nerve is generally narrowed at the level of compression and swollen proximally typically with loss of the normal fascicular pattern.

Summary A complete examination of the elbow will cover Biceps tendon Anterior Joint Recess (Brachialis Tendon) Radial Nerve/PIN Lateral Elbow (Lateral Epicondylitis) Medial Elbow (Medial Epicondylitis) Triceps Ulnar nerve/Cubital Tunnel Always correlate your U/S findings to the clinical H&P and tailor your exam accordingly!