Fracture of the ulna - causes, symptoms, diagnosis and treatment

Anatomy of the elbow joint[edit | edit code]

Bones of the elbow joint

Bone anatomy[edit | edit code]

Anatomy of the Elbow Joint
The elbow joint is the articulation of three bones: the humerus, the ulna, and the radius. The shoulder-elbow joint is a trochlear joint; it is formed by the trochlea of the medial condyle of the humerus and the lunate notch of the ulna. The ulnar and coronoid processes, which deepen the semilunar notch, contribute to an increase in the area of the articular surface. The humeroradial joint is formed by the head of the radius and the head of the condyle of the humerus. The joint between the ulna and radius is formed by the head of the radius and the radial notch of the ulna. These joints, together with the ligamentous and muscular apparatus, provide flexion and extension at the elbow joint, as well as pronation and supination of the forearm.

Biomechanics of the elbow joint on x-ray

Anatomy of ligaments[edit | edit code]

Ligaments of the elbow joint
Ligaments are thickened areas of the joint capsule that provide stability to the joint. The elbow joint is surrounded by a complex network of ligaments. The lateral part of the joint is strengthened by a complex of four ligaments: the radial collateral ligament, the annular ligament of the radius, the accessory lateral collateral ligament, and the lateral ulnar collateral ligament. The radial collateral ligament begins from the lateral epicondyle of the humerus and, expanding in the distal direction, merges with the deep fibers of the annular ligament of the radius, strengthens the latter and ensures stability of the elbow joint under varus load (adduction of the forearm). The annular ligament of the radius attaches to the anterior and posterior surfaces of the radial notch of the ulna, forming a ring around the head and neck of the radius; it provides stability during pronation and supination. The distal end of the accessory lateral collateral ligament is attached to the tubercle of the supinator crest of the ulna; The proximal end of the ligament merges with the fibers of the annular ligament of the radius. The lateral ulnar collateral ligament is attached with its proximal end to the lateral epicondyle of the humerus, and its distal end to the crest of the supinator of the ulna under the fascia of this muscle. It provides stability to the lateral aspect of the elbow joint, reduces stress during forearm rotation, and supports the radial head posteriorly.

The medial part of the elbow joint is also strengthened by a ligamentous complex. It includes the anterior, posterior and transverse (Cooper's ligament) portions of the ulnar collateral ligament. The anterior portion of the ulnar collateral ligament is of greatest importance in counteracting the valgus load on the elbow joint (forearm abduction). It is attached to the medial epicondyle of the humerus and to the tip of the coronoid process and provides static and dynamic stability of the elbow joint during throwing movements, accompanied by flexion from 20 to 120°. The posterior portion of the ulnar collateral ligament strengthens the medial sections of the elbow joint during pronation. Its attachment points are the lateral epicondyle of the humerus and the olecranon process. The humeroulnohumeral joint, radial and ulnar collateral ligaments are the three main stabilizing structures of the elbow joint. Damage to any of them leads to an increase in the load on secondary stabilizing structures, which include the head of the radius, the anterior and posterior parts of the capsule of the elbow joint, the attachment points of the anterior and posterior groups of the forearm muscles, as well as the ulnaris, triceps and brachialis muscles.

Muscle anatomy[edit | edit code]

Muscles of the elbow joint
To ensure precise coordinated movements in the joint, balanced muscle contraction is necessary. Movement in the elbow joint is provided by the following muscles. Along the anterior surface, the brachialis muscle is attached to the coronoid process of the ulna, while its antagonist, the triceps muscle, is attached by a flat broad tendon to the olecranon process of the ulna. The extensor muscles of the superficial layer of the posterior muscle group of the forearm originate from the lateral epicondyle of the shoulder; these include the extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, and flexor carpi ulnaris muscles. On the other side of the distal epiphysis of the humerus, from the medial epicondyle and the medial epicondylar crest, the anterior group of muscles of the forearm (flexors and pronators) originates. It includes the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, and flexor carpi ulnaris muscles.

Nerves[edit | edit code]

Innervation of the muscles of the elbow joint is carried out by three main nerves of the free lower limb: the radial nerve (including the posterior interosseous), passing in front and lateral to the joint, the median nerve, passing along the midline in front, and the ulnar nerve, passing along the posteromedial surface of the elbow region. The radial nerve is formed by the posterior bundle of the brachial plexus (roots C6, C7 and Thl); it innervates the triceps muscle, the supinator muscle, and the extensors of the wrist and fingers. The ulnar nerve is formed from the medial bundle of the brachial plexus (C7 and Thl roots) and innervates the flexor carpi ulnaris, deep digital flexors and lumbrical muscles of the ring and little fingers, dorsal and palmar interosseous muscles, the adductor pollicis muscle, as well as the muscles of the eminence of the little finger ( Opposite minimi muscle, adductor digiti minimi, and flexor digiti minimi). The median nerve is formed by the lateral and medial fascicles of the brachial plexus (roots C6, C7 and Thl) and innervates palmaris longus, pronator teres, flexor carpi radialis, deep flexors of the index and middle fingers, flexor digitorum superficialis, flexor pollicis longus, pronator quadratus, lumbricals muscles of the thumb and index finger, as well as the muscles of the eminence of the thumb (opponus pollicis, abductor pollicis and flexor pollicis).

Compression of these nerves, usually reversible, is a common cause of elbow pain. The radial nerve may be compressed by the fibrous arch of the lateral head of the triceps muscle, the arcade of Froese, the insertion of the extensor carpi radialis brevis, and adjacent structures. Compression of the ulnar nerve is possible in the area of the supracondylar process of the humerus, in the area of the arcade of Straders, at the insertion of the flexor carpi ulnaris, in the ulnar tunnel of the wrist (see section “Cubital tunnel syndrome”). The median nerve may be compressed by the supracondylar process of the humerus and its attachments, the ligament of Straders, the arch of the superficial flexor digitorum, the biceps brachii aponeurosis, or the pronator teres muscle. Compression of the median nerve is also possible in the carpal tunnel.

Treatment

Treatment of styloiditis of the styloid process when affected on the radial and ulnar sides is the same and includes:

Load limitation
The use of non-steroidal anti-inflammatory drugs (NSAIDs) orally and locally
Blockades with diprospan or kenalog
Physiotherapy
Kinesio taping

It is recommended to remove loads for 1-2 months. As for drug therapy, for wrist styloiditis they begin with taking anti-inflammatory drugs (NSAIDs) orally (Voltaren, Nimesil, etc.) with simultaneous local application (Voltaren-gel, Indovazin-gel).

At the same time, the therapy can be supplemented with kinesio taping and physiotherapy. If therapy is ineffective within 7 days, blockades with diprospan are prescribed (from 1 to 3 with an interval of 5 to 7 days). If the pain syndrome is significantly severe, blockades can be started immediately, without waiting for the effect of NSAIDs.

In general, styloiditis responds well to treatment, but in some cases the disease becomes chronic. For frequent exacerbations that are difficult to treat, surgical intervention may be indicated.

Radiation styloiditis

The main manifestation is pain. It occurs in the area of the wrist joint on the radial side (thumb side). Pain can occur either acutely (for example, due to injury) or increase gradually (with chronic overload). Characteristically, there is pain when moving the wrist joint or thumb. Pain at rest is much less common and can occur with very severe inflammation or with a chronic long-term course of the disease.

There are usually no changes upon external examination. In rare cases, a slight swelling may be found above the styloid process. There is practically no redness of the skin.

Palpation in the area of the styloid process is painful. Movement in the wrist joint and/or thumb is moderately painful.

There are several tests for diagnosing radial styloiditis.

Classification of radial head fractures

Historically, radial head fractures have been delineated according to the Mason classification, which distinguishes three types of injury:

1. Marginal fracture (without displacement or movement of fragments).

2. Marginal fracture (with displacement and movement of fragments).

3. Multicomminuted (in which the entire head of the radial bones is involved in the process).

(A fourth type was added to designate a fracture of the head with dislocation.) 4. Fracture accompanied by dislocation of the bones of the forearm.

There is also the Essex-Lopresti fracture, described in 1951. It is characterized by a comminuted fracture of the head of the radius, rupture of the distal radioulnar joint and dislocation of the head of the ulna towards the wrist.

And the so-called terrible triad of the elbow (dislocation of the bones of the forearm, fracture of the coronoid process and fracture of the head of the radius).

As a rule, only the first type of fractures does not require surgical intervention.

Blood supply and innervation of the adjacent area

Complete nutrition of the elbow joint is provided by the powerful blood network that surrounds it. Arterial blood enters the muscle fibers adjacent to the articular surface from the superior and inferior collateral ulnar arteries, as well as the recurrent, median and radial arteries. Having enriched the cells and tissues with oxygen and nutrients necessary to maintain physiological functions, it is sent through the veins of the same name to the venous basins of the upper extremities - the brachial, ulnar and radial. The lymph flow of the elbow joint passes in a similar way, moving through the lymphatic vessels to the elbow lymph nodes.

The innervation of the capsule that unites the sections of the elbow joint is carried out by the largest nerve fibers of the arm - the branches of the ulnar, radial and median nerves. This explains the high sensitivity of the tissues adjacent to the elbow and the particular pain of the resulting injuries.

Physiology of the human elbow joint

The normal physiology of the human elbow joint implies fairly extensive mobility: even without special training, the bones of the forearm and shoulder can rotate 90°, bend up to 150° and extend another 10° in the opposite direction (that is, as if beyond the elbow). Moreover, these degrees are not the limit - with certain skill and careful training, the mobility of the elbow joint can be increased several times, clearly demonstrating the almost limitless capabilities of the human body.

It should be borne in mind that such functionality requires special attention when loading the elbow joint. Although it belongs to the group of hanging ones and does not formally serve as a support, the size and number of loads does not decrease from this. This is particularly due to physical work, weight lifting, sports training and other activities that involve the upper extremities. As a result, any careless movement performed without proper preparation and warming up of the ligamentous-muscular system can be fraught with a painful elbow injury that requires long-term treatment. Therefore, you should take care of your own body and regularly strengthen it with gradually increasing loads as part of physical exercises - only in this way can you develop your elbow joints, making your arms truly strong, resilient and flexible.

Development

The ulna begins at birth as a long bony shaft known as the diaphysis, covered with hyaline cartilage at both ends. Around age 4, hyaline cartilage at the distal end near the wrist begins to ossify and form small bony structures known as the distal epiphysis. A thin layer of hyaline cartilage, known as epiphyseal cartilage, or growth plate, remains between the diaphysis and the newly formed bone. It grows along the growth plate, which in turn grows to prevent fusion of the diaphysis and epiphysis. At approximately 10 years of age, the proximal end of the process begins to ossify and form the proximal epiphysis. These three bones continue to grow and remain separated by epiphyseal plates until late puberty and early adulthood, when they fuse to form a single ulna bone.

Diagnosis of radius fractures

Diagnosis of an elbow injury begins with interviewing the patient. The doctor must find out what the mechanism of injury was. Assess whether there are visible deformities, swelling, crepitus of bone fragments (crunching), subcutaneous hemorrhage (if the fracture is 2 or more days old), i.e. symptoms characteristic of a fracture.

In almost all cases of injury to the elbow joint, radiography is performed. As a rule, in the frontal and lateral projections, although in the oblique projection the head of the radial bone is very well visualized. If the injury was minor and on radiographs we see the normal location of the head of the radial bone, then the diagnosis of a fracture is questioned.

Radial head fractures can often be nondisplaced and therefore easily missed on plain radiographs. Even if a fracture is not visible on an x-ray, this does not mean that it does not exist. After 7 days, control radiographs must be taken to rule out a fracture. It is during this time that resorption of the fracture site occurs and can be clearly seen in the photographs.

Intra-articular fractures are necessarily accompanied by hemorrhage into the joint, which can be determined by ultrasound.

Computed tomography (CT) and magnetic resonance imaging (MRI) are used in the diagnosis of complex radial head fractures and for preoperative and postoperative management.

Internal structure

The hollow medullary cavity in the center of the bone is filled with a soft, fatty substance known as yellow marrow. Yellow bone marrow contains many adipocytes and stores energy for the body in the form of triglycerides or fats.

Surrounding the medullary cavity is hard, dense, compact bone made of a mineral matrix and collagen fibers. The combination of collagen and minerals, including calcium, gives bones greater strength and flexibility.

The ends of the ulna are supported by cancellous bone, which increases the strength of compact bone tissue near the joints without significantly increasing bone mass. In each region, cancellous bone is composed of many thin columns known as trabeculae, which act like steel bridge beams to support the loads placed on the bone. Red bone marrow is found in the spaces between the trabeculae and contains many stem cells that produce blood cells.

The ulna ends in a thin layer of hyaline cartilage, which covers compact bone tissue and protects it from overstrain in the joints. Hyaline cartilage is smooth as ice to help the bone glide at the joints. It is also a shock absorber to absorb impacts on the joints. The outer surface (excluding the joint area) is covered with a thin fibrous layer known as periosteum. The periosteum consists of a dense weave of collagen fibers that extend onto the tendons and ligaments that attach to the ulna.

ATLAS OF HUMAN ANATOMY - G.L. Bilic - 2014