The Elbow joint is a complex joint composed of three individual joint contained within a common articular cavity. The elbow is the joint where three lengthy bones meet in the central portion of the arm. The bone of the superior arm (humerus) meets the inner bone of the forearm (ulna) and the external bone of the forearm (radius) to form a hinge joint. The radius and ulna also meet in the elbow to allow for revolving of the forearm. The elbow functions to move the arm like a hinge (forward and backward) and in rotation (twisting outward and inward). The biceps muscle is the major muscle that flexes the elbow hinge. The triceps muscle is the major muscle that extends the elbow hinge. The outer bone of the elbow is referred to as the lateral epicondyle and is a part of the humerus bone. Tendons are attached to this area which can be injured, causing inflammation or tendinitis (lateral epicondylitis, or "tennis elbow"). The inner portion of the elbow is a bony prominence called the medial epicondyle. Additional tendons from the muscles join here and can be injured, causing medial epicondylitis, "golfer's elbow." A fluid-filled sac (bursa), which serves to reduce friction, overlies the tip of the elbow (olecranon bursa). The elbow can be affected by inflammation of the tendons or the bursae (plural for bursa) or conditions that affect the bonesand joints, such as fractures, arthritis, or nerve impatience. Joint tenderness in the jostle can result from injury or disease involving any of these structures.
Anatomical Features
Carrying angle: The carrying angle is the normal outward deviation of the extended and supinated forearm in relation to the axis of the arm. This is due to the shape of the trochlea of humerous. It is spool-shaped and the medial lip off the spool is larger and extends distally than its lateral lip. Hence it pushes the ulna laterally. The normal carrying angle is decreased in malunited supracondylar fractures.
Three Bony Points: The medial epicondyle, lateral epicondyleand oplecranon form the three bony points. The relationship between these three points is an important sign. Normally they formed an inverted triangle on 90 degree of flexion, but on extension, they all come to lie in a straight line.
Anconeous Triangle: The radial head, lateral epicondyle in tip of olecranon form a triangle. This space is occupied by anconeus muscle overlying joint capsule. When fluid collection occurs in the joint, this triangle buldges out.
History
The common complaints are pain, stiffness, deformity and occasionally locking episodes. History of massage by native bonesetters is an important one as they may alter the pre-existing problem or compound the disease by precipating myositis mass formation.
Examination
Inspection
The patient should be examined in sitting or standing position with both elbows by the side of the chest and palms looking forwards (i.e.) anatomical position. It should be examined from front, back, and in profile views.
1. Carrying angle: The forearm must be in full spination and extension because when the forearm is in flexion or pronation, the carrying angle is lost.
2. Deformity: Flexion deformity may occur in effusion, arthritis or unreduced posteriordislocation of elbow. Hyperextension may be seen in ligamentous laxity or malunited supracondylar fractures.
3. Scars or sinuses
4. Swelling: In cases of effusion of elbow joint, the normal hollows on either side of olecranon are obliterated as the synovial cavity is nearest to surface and the posterior capsule is thin and lax in the posterior aspect. A localized swelling over the olecranon process may be olecranon bursitis (miner's or student's elbow). Swelling on either side of triceps tendon may occur in inflammation of bursa beneath the triceps tendon. Swelling in front of the elbow may be bicipitoradial bursitis or in huge effusions of elbow joint, anterior swelling may be seen.
5. Muscle wasting: In arthritis or prolonged immobilization of elbow, the surrounding muscles undergo atrophy. Sometimes, the tricepstendon seen prominently in the posterior aspect in unreduced posterior dislocation of elbow.
Palpation
1. Temperature: Increased in arthritis, buritis or active myositis ossificans.
2. Tenderness: Localized tenderness is a valuable diagnostic sign. Tenderness localized to lateral epicondyle is suggestive of tennis elbow, otherwise known as lateral epicondylitis. In golfer's elbow, medial epicondyle tenderness will be present. Joint line tenderness should be looked for in the sulcus between lateral epicondyle and head of radius with elbow flexed to 35-450 and by alternate pronation and supination.
3. Bony components: With the elbow semiflexed the lower end of humerus (i.e.) supracondylar ridges are palpated for thickening or irregularity. They are normally felt as sharp bony ridges.
4. Swelling: The elbow should be palpated all around for the presence of abnormally bony mass due to myositis. Effusion in the joint may cause paraolecranon swellings of cystic nature in the anconeus triangle. These two will demonstrate cross-fluctuation. This will help in differentiating from the bursitis of triceps bursa.
Movements
There are two components:
1. Humeroulnar: With the arm placed over a table and the forearm in supination, the flexion of the elbow is measured. Normally, the flexion should be unrestrained until the soft tissues in front of the elbow approximate each other. The fingertips should be able to touch the shoulder. This measures normally up to 145 degree-160 degree.
2. Superior radioulnar joint: The movements occurring in this joint are pronation and supination. They are measured with the elbow flexed to 90 degree. Supination is from 0-80 degree and pronation is from 0-75 degree. Abnormalities in superior radioulnar joint, forearm bones and distal radioulnar joint will cause restriction of pronation and supination.
Neurological Examination
Since elbow joint is closely related to all three nerves of the upper limb, they should be tested independently.
Lymphatic system: Epitrochlear lymph node should be looked for specifically. The elbow is flexed to 90 degree and with the fingertips; the region anterior to medial intramuscular septum above the medial epicondyle is palpated.
Special tests
Cozen's test: This is a test for lateral epicondylitis. On extending the clenched fist, the patient experiences pain in lateral epicondyle.
Mill's manoeuvre: Passive flexion of the wrist with pronated forearm also causes pain in cases of tennis elbow.
Lifting a jug or chair: This will also cause pain in lateral epicondylitis.
