Introduction 

Brief overview 

The main epicondyle is a small bony structure at the lateral side of the elbow joint and that tells of epicondylar bone.¹ Its location results in the origin of important muscles and tendons that move and control the wrist and fingers. It is located on the lateral side of the humerus right above the elbow joint which is important for arm function.² As with most parts of the human body, it is important but can be neglected until there is damage inflicted. This is prevented by most people as an overuse injury as they experience pain, discomfort, immobilization, and even weakness.³ Adapting to these matters also helps in dealing with managing medical attention and intervention.

Purpose of the article 

Most practitioners should already have an idea regarding issues such as epicondylitis, tendon tears, and tendinopathy, however, very few people appreciate the lateral epicondyle region and all of its intricate details.⁴ This knowledge is equally essential to other healthcare providers but especially to orthopaedic doctors, physiotherapists, and all those specialities trained in traumatic and sports medicine.

Anatomy of the lateral epicondyle

 The lateral epicondyle is a small protrusion on the lateral side lower end of the humerus bone on the arm, just above the elbow joint.⁵ It gives rise to various muscles and tendons that enable wrist and finger movements.

Location and structures

The lateral epicondyle is situated on the outer side of the humerus bone, roughly 1-2 cm above the elbow joint.¹ It is a small rounded feature that extends from the elbow to the lower side of the head of the humerus bone.

Muscles and tendons

In detail, the lateral epicondyle gives rise to several important muscles and tendons which include: 

1.  Extensor Carpi Radialis Brevis (ECRB) Tendon: Extends from lateral epicondyle into the 3rd metacarpal bone²
2. Extensor Carpi Radialis Longus (ECRL) Tendon: Comes from the lower part of the supracondylar ridge and reaches the base of the 2nd metacarpal bone³
3. Extensor Digitorum Communis (EDC) Tendon: Starts from lateral epicondyle down to the base of the middle and end bones of the fingers⁴
4. Extensor Digiti Minimi (EDM) Tendon - It comes from the lateral epicondyle, ending at the middle and distal phalanges base of the little finger⁵

Blood supply 

The side bone point gets blood from two main blood ways.¹ The first is the side-arm help blood way, and the next is the middle help blood way. The side nerve gives feeling to the parts that start from this bone point.

Clinical significance

The side bone point often gets hurt. This includes side bone pain, breaks in cords, and sick cords.² Knowing the parts of the side bone point helps to find and fix these issues.

Associated tendons

Extensor carpi radialis brevis (ECRB) tendon³

• Starts: Side top knob of the upper arm bone
• Ends: Bottom of the middle hand bone
• Job: Helps lift the wrist and move it to the thumb side
• Blood: Comes from the side wrist artery
• Nerves: From the thumb side arm nerve
• Health Point: Often hurt in tennis elbow

Extensor carpi radialis longus (ECRL) tendon⁴

• Starts: Lower part of the side top ridge of the upper arm bone
• Ends: Base of the second hand bone
• Job: Helps lift the wrist and move it to the thumb side
• Blood: Comes from the side wrist artery
• Nerves: From the thumb side arm nerve
• Health Point: Can get hurt in tennis elbow too, but not as much as ECRB tendon

Extensor digitorum communis (EDC) tendon⁵

• Starts: Side bump of the upper arm bone
• Ends: Mid and tip parts of finger bones
• Job: Helps stretch out fingers
• Blood Comes From: Side arm artery
• Nerve Control: Arm nerve on the thumb side
• Health Point: Might get hurt if side elbow is sore, making it hard to stretch fingers

Extensor digiti minimi (EDM) tendon¹

• Starts: Side bump of the upper arm bone
• Ends: Mid and tip parts of the little finger bones
• Job: Helps stretch out the little finger 
• Blood Comes From: Side arm artery
• Nerve Control: Arm nerve on the thumb side
• Health Point: Can get hurt if the side elbow is sore, making it hard to stretch the little finger

Clinical significance 

Tennis elbow (Lateral epicondylitis)

Tennis elbow, otherwise known as lateral epicondylitis is a common condition constituting the inflammation of the tendons attaching to the lateral epicondyle.² Too much repetitive use of the tendons, especially the ECRB tendon, could result in pain and inflammation. 

Definition³

It is characterised by pain and tenderness over the lateral aspect of the elbow along with the following: weakness of the grip strength during activities that comprehend the wrist extending.

Diagnosis

Physical examination, X-rays, and magnetic resonance imaging (MRI) may be advised by a doctor to confirm the condition.⁴ We perform electromyography (EMG) to rule out neurogenic causes and lateral epicondylitis.

Treatment

The elbow, just like other body parts, can get stiff, sore, and swollen if it can't move much. Using the RICE method can help in the first week to handle the pain.⁵ Physical therapy and pills that fight swelling are the main ways to treat it if it lasts long. If it's very bad, surgery may be needed.

Tendon rupture

Definition

A tendon rupture happens when a tendon snaps abruptly or tears causing it to lose some functions and pain.¹

Causes

A sudden or repetitive strain on the tendon may cause the tendon to break or rupture the tendon. It is more common in the leg, the Achilles tendon and the elbow, such as from overloading. Other things can also break a bone or cause a muscle to strain as well.²

Symptoms

Symptoms of a tendon torn if you feel a sharp, great pain, hear a loud snap, see swelling and can't move that part of your body well.³

Diagnosis

Diagnostic tests can include a physical examination and imaging such as X-rays, MRI etc to know the depth of the condition.⁴ 

Treatment

The only effective way to repair a torn tendon is to have surgery.⁵

Tendinopathy

Definition

It is a very slow and continuous degeneration of tendons which often leads to pain and stiffness and creates tendinopathy. Overusing it is probably the greatest reason for tendinopathy.

The ECRB tendon is a tendon that’s not made to handle repetitive strain over and over again.¹

Symptoms

Pain, stiffness or weakness is discovered in the arm or hand; actually, traces of muscles in the forearm become a common symptom of tennis elbow.²

Physical examination 

Imaging studies (e.g. X-rays, MRI), and ultrasound scans are ways to diagnose the condition and see the spread of the disease.³

Treatment 

Treatment options for it depend largely on the intensity of the factors causing it. Decreasing the inflammation using rest and immune response in the area is part of the repair process for tendinopathy.⁴

Other conditions 

Any of these interventions, however, may exacerbate weakness, making the patient drop it more proximal in the wrist.⁵

Radial tunnel syndrome

Compression of the radial nerve can lead to pain and numbness as well as tingling in your arm or hand

Lateral epicondyle fracture

This can be a break of the lateral epicondyle of the humerus which tends to make you feel swelling, and pain, and make it hard to move your arm. 

Elbow instability

Elbow joint instability is the feeling that the elbow is moving or unstable leading to give you trouble in the elbow joint like pain, stiffness, or less mobility to move the arm.

FAQs

What is the side bone bump near the top of your arm?

The side bone bump is a small hard spot on the outer part of the upper arm bone, just above the bend in the arm.

What bits start from this side bone bump?

The bits that start from this side bump are the short and long outer wrist lifters, the common finger stretcher, and the small finger stretcher.

What is side bone bump pain?

Side bone bump pain, also known as tennis elbow, is a usual pain from the swelling of the bits that stick to the side bone bump.

What are the signs of this pain?

The signs of this pain are hurt and soreness on the outer part of the elbow, weak hands, and trouble with stretching the wrist or fingers.

How do they fix tennis elbow?

To deal with tennis elbow, they use methods like rest, ice, pressing the area, and lifting it (RICE). They also try physical therapy and drugs to bring down swelling. In some cases, surgery might be needed.

What is a tendon tear?

 A tendon tear takes place when a tendon splits or breaks, causing pain and making it hard to move.

What is tendinopathy?

 Tendinopathy is considered when there is break down over time of tendon, causing pain and making it stiff to move.

Summary

The lateral epicondyle is a tiny bone structure found on the outer side of the humerus (upper arm bone), right above the elbow joint. It is the starting point for many important muscles and tendons that go to the wrist and fingers. Knowing the build of the lateral epicondyle and the tendons linked with this spot is key to seeing and taking care of different issues like lateral epicondylitis, tendon break and tendinopathy.