Search databaseBooksAll DatabasesAssemblyBiocollectionsBioProjectBioSampleBioSystemsBooksClinVarConserved DomainsdbGaPdbVarGeneGenomeGEO DataSetsGEO ProfilesGTRHomoloGeneIdentical Protein GroupsMedGenMeSHjajalger2018.org internet Sitejajalger2018.org CatalogNucleotideOMIMPMCPopSetProteinProtein ClustersProtein household ModelsPubChem BioAssayPubChem CompoundPubChem SubstancePubMedSNPSRAStructureTaxonomyToolKitToolKitAllToolKitBookgh

jajalger2018.org Bookshelf. A organization of the nationwide Library that Medicine, national Institutes of Health.

You are watching: Is the shoulder proximal to the elbow

StatPearls . Endowment Island (FL): StatPearls Publishing; 2021 Jan-.


*

Introduction

The elbow joint, although non-weight bearing, might be the most complex joint in the human being body. The elbow is a synovial hinge joint made up of articulations of mainly the distal humerus and also the proximal ulna. However, articulations exist in between the proximal radius and the humerus as well as the proximal radius and also ulna.  The 3 articulations are referred to as the ulnohumeral, radiohumeral, and also proximal radioulnar joints respectively. Many of the muscle of both the upper and also lower eight either overcome or connect to at least one ingredient of the elbow share making the no surprise that after the shoulder, the elbow share is the second most frequently injured joint in sports-related injuries.<1>


Structure and Function

The elbow is a complicated synovial share which enables for significant movement and duty primarily in the kind of extension and also flexion, however, the elbow joint additionally facilitates motion in the hand in the form of supination and also pronation that the forearm. The main stability that the elbow joint outcomes from the osseous articulations that the trochlea of the humerus and the ulnar olecranon. The olecranon resembles a scoop or a wrench in i m sorry a landmark referred to as the trochlear notch, fits approximately the trochlea the the humerus and also serves as the major pivot allude during flexion and also extension that the elbow joint.  The trochlear notch wraps approximately the humerus nearly 180 degrees, while the trochlea the the humerus is vast with a central groove, this allows for a chop conforming the the two structures, adding to the stability.  after the osseous articulations that the humerus and ulna (ulnohumeral articulation), the remainder of the significant stability components of the elbow joint originates from two solid ligaments in the kind of the medial collateral ligament (MCL) and the lateral collateral ligament (LCL).  Both the LCL and the MCL kind into the joint capsule to administer further stability.<2>

The Medial collateral ligament is a triangular-shaped ligament consisted of of three smaller sized ligaments called the anterior slope ligament, posterior oblique ligament, and the transverse ligament, additionally sometimes referred to as Cooper"s ligament. The anterior oblique ligament originates native the anterior inferior surface of the medial epicondyle of the humerus and also inserts top top the coronoid process of the ulna. The anterior tilt ligament is the strongest and also most crucial medial stabilizer the the elbow joint and also protects versus excessive valgus forces.   The posterior oblique ligament likewise originates indigenous the medial epicondyle yet as its surname suggests, operation posteriorly come insert ~ above the olecranon of the ulna.  The transverse ligament passes between the previous two, to run from the coronoid procedure and the guideline of the olecranon.<2>

The lateral collateral ligament is also composed of 3 parts; the annular ligament, the lateral radial collateral ligament, and the lateral ulnar collateral ligament.  The three components of the LCL provide stability throughout varus stresses applied on the elbow and also posterolateral rotational stability.  The lateral ulnar collateral ligament is the primary stabilizer in posterolateral rotational framework as it the cross over the inferior facet of the radial head, originating from the lateral epicondyle of the humerus and also inserting at the supinator crest of the ulna.  The annular ligament stabilizes the proximal radioulnar joint and originates and also inserts at the sigmoid notch of the ulna as it wraps approximately the neck that the radius.<2>

The cubital tunnel is a clinically far-ranging space permitting the i of the ulnar nerve.  The roof of the cubital tunnel is created by the arcuate (Osborne’s) ligament running from the medial epicondyle come the olecranon the the ulna. The floor of the cubital tunnel is comprised of the MCL, while the anterior, posterior, and also lateral borders are comprised of the medial epicondyle, medial head the the triceps brachii, and the olecranon respectively.  

As a synovial joint, the elbow has a synovial membrane and a joint capsule which are separated from each various other by fat pads.  this fat pads are situated superficial to areas of stress.  These locations include the olecranon, coronoid and radial fossas.  during flexion and extension, this fat pads room pulled far by attachments come the brachialis and also the triceps brachii to allow space for bony processes. A lubricating bursa, namely the olecranon bursa, facilitates triceps action. This bursa serves together a lubricating component between the olecranon procedure of the ulna and the triceps tendon the insertion.<2>


Embryology

During the 12th week that gestation, ossification begins in the skeleton that make up the elbow joint. This ossification beginning in the lower epiphysis that the humerus, followed by the trochlear notch of the ulna and also the head that the radius. In the direction of the finish of the embryonic period,  the groove in between the olecranon process and the posterior element of the medial epicondyle is visible. The tunnel the the ulnar nerve creates at the posterior facet of the medial epicondyle complied with by the elbow share cavity in ~ the level that the humeroradial and also humeroulnar joints. Next, the annular ligament develops, complied with up by the development of the joint cavity that the remarkable radioulnar joint.<3><4>


Blood Supply and Lymphatics

The elbow joint serves as a crossing for many of the neurovasculature in the top extremity.  The superficial nature of most of these structures enables a provider to visualize many of these frameworks using ultrasound.  The brachial artery is one of the continuations the the axillary artery and also is the source of all the key arteries feeding right into the elbow joint.  The branches that the brachial artery encompass a deep brachial artery which courses posteriorly to give rise come a few other small arteries which ultimately anastomose with the radial artery. The majority of the blood flow travels with the brachial artery distally and also branches into the radial and also ulnar arteries. 

The major lymphatic structures roughly the elbow joint room the deep and superficial cubital lymph nodes, and also the epitrochlear and also supratrochlear lymph nodes, the latter making up up to 5 nodes lying exceptional to the medial epicondyle. Lymph drains increase the arm and passes with the deep brachial lymph nodes, eventually finishing up in the axillary lymph nodes.<5>


Nerves

The nerves the cross the elbow joint predominately innervate frameworks of the forearm and also hand. One of the significant nerves responsible for exhilaration on the elbow joint is the musculocutaneous nerve.  This nerve never ever crosses the elbow joint itself, yet rather innervates both the biceps brachii, the muscle the accounts for the majority of supination as well as some elbow flexion, and the brachialis muscle, i beg your pardon is responsible because that elbow flexion. 

The radial nerve starts medially in the proximal humerus, climate spirals posteriorly and also laterally right into the spiral groove.  The radial nerve the cross the elbow joint together it courses laterally and enters the groove for the radial nerve in the distal humerus.  The radial nerve innervates five muscles that impact the elbow joint including the brachialis (lateral portion), the anconeus, the supinator muscle, brachioradialis, and also triceps brachii.

The ulnar nerve stays in the medial arm and also travels native the anterior compartment to the posterior compartment whereby it enters into the cubital tunnel and the groove for the ulnar nerve.  The ulnar nerve innervates muscle in the forearm and also hand.

The typical nerve traverses the elbow joint anteriorly and also continues distally to innervate the muscles in the forearm and also hand.

Also spanning the elbow share is the lateral antebrachial cutaneous nerve and also the medial antebrachial cutaneous nerve acquired from the musculocutaneous and also radial nerves respectively.  These two nerves supply sensory information for the skin that the forearm.<6>


Muscles

Many muscles overcome over and also attach roughly the elbow joint.  this muscles room responsible because that the second stabilization of the joint.  The majority of the muscles originating from the elbow joint administer very little movement at the elbow share itself, but rather act as flexors and also extensors of the wrist, hand, and digits. Contribution to elbow security comes in the kind of protection versus varus and also valgus forces. Muscles that protect versus valgus pressures by initiating a varus force incorporate the flexor digitorum superficialis, flexor carpi ulnaris, flexor carpi radialis, and also the pronator teres.  muscles that contribute to varus security by initiating a valgus force encompass extensor digitorum communis, extensor carpi radialis brevis and also longus, anconeus, and extensor carpi ulnaris.

Muscles i beg your pardon act primarily on the elbow joint include those responsible because that flexion, consisting of biceps brachii, brachioradialis, and also brachialis.  The biceps brachii has a modest impact on elbow flexion and acts as the primary muscle responsible because that supination.  The biceps brachii is especially distinct as it has two distal attachments in ~ the elbow joint, a more laterally oriented tendon inserting top top the proximal radius, and a medially oriented aponeurosis which proceeds into the fascia that the proximal forearm.  extension of the elbow joint is accomplished nearly entirely from contraction of the triceps brachii with really modest action from the anconeus muscle.<6><7>


Physiologic Variants

There room a couple of normal osseous and also non-osseous variants in ~ the elbow joint, as well as some abnormal osseous variants that can reason deficits in function.

Pseudodefect the the capitellum is just one of the common osseous variants the exist.  In this variant, a groove exists in between the capitellum and the lateral epicondyle.  This groove deserve to be viewed on MRI and can periodically be mistaken for an osteochondral defect.

The supracondylar procedure is a bony spur that can display up in approximately 3% that individuals.  These have the right to sometimes be mistaken because that osteochondromas that the humerus.  In some situations of significant supracondylar processes, median nerve and much more rarely, brachial artery compression deserve to occur due to a fibrous band called the ligament the Struthers which operation from the supracondylar process to the medial epicondyle.

Ligamentous variations additionally exist.  In number of studies, four various variants of ulnar collateral ligament to be identified, while 23% the the specimens studied included an accessory ligament.<6>

Congenital radioulnar synostosis is a rare anomaly in i m sorry the fail of segmentation results in the combination of the radius and also the ulna.  Flexion and also extension room unaffected through the condition; however, supination and pronation are.  This condition may lead to after-effects in the kind of too much strain on the shoulder and wrist.<8>


Surgical Considerations

Medial collateral ligament tears are commonly seen in expert baseball players because of the extreme amount of torque inserted on the elbow share by pitchers.  "Tommy john surgery" has come to be the much more recognizable name for the surgical procedure performed to repair the medial (ulnar) ligament.  surgical procedure success is high and also the go back to play is about 90%.<9>

Medial epicondylitis (golfer’s elbow) is very common specifically in one aging populace and is brought about by repetitive flexion and also valgus force on the elbow joint.  Typically, these space treated conservatively using NSAIDs, ice, and also steroid injections. However, treatment-refractory epicondylitis may be treated arthroscopically and also has been presented to alleviate pain in an impacted individual. The surgery consists of debridement the the common flexor tendon insertion at the medial epicondyle, therefore relieving stress on the medial epicondyle.<10>

Distal biceps tendon ruptures account for around 10% of every biceps ruptures and occur after ~ a sudden expansion force used to a flexed arm.  The bulk of these injuries are complete ruptures wherein the tendon of insertion avulses from the radial tuberosity.  Tears that the bicipital aponeurosis might or might not take place in this cases. Operative treatment where the tendon is reinserted ~ above the radial tuberosity is generally wanted unless the patient is yonsei in which instance management is non-surgical. The clinical result of such surgeries is usually very positive.<11>

Osteochondritis dissecans that the elbow is one avascular necrosis the the articular cartilage and also the subchondral bone in the capitellum.  it predominately occurs in young athletes and also can be treated using debridement, drilling, micro-fracturing, and fragment fixation steps when conservative actions fail.<12>

There are plenty of other surgical considerations for the elbow joint consisting of those related to osseous and other ligamentous injuries the may take place with dislocation and also blunt trauma injuries.  various other minor procedures are additionally seen in instances of bursitis or various other inflammatory conditions.


Clinical Significance

Nursemaid"s elbow is just one of the an ext common pediatric elbow injuries in kids aged 6 months to 5 years.  additionally called radial head subluxation, the is usually caused by one abrupt pulling force on the hand or reduced arm once the eight is outstretched, leading to a displacement the the annular ligament.  The annular ligament is responsible for holding the radius and also ulna in close proximity and the proximal radioulnar joint. In this kind of injury, neither the bone nor the ligament is have to damaged but instead have actually slipped out of their normal positioning. Upon injury, the patient will certainly be in major pain that will frequently subside quickly.  kids will organize their arm on your lap or close against their body and also refuse to usage it.  therapy for elbow subluxation is non-invasive and also can typically be excellent in one outpatient office by to reduce the joint.  There space two ways this is generally done.  The an initial method is the supination flexion method. This is done by stabilizing the elbow through one eight while flexing the child’s arm to the shoulder and also supinating the arm simultaneously.  You have to feel the joint mitigate with the stability hand.<13>  The patient will be in some discomfort till joint reduction completes.  Another technique gaining popular is the hyperpronation method; in current studies, it has actually been discovered the hyperpronation technique may have greater first-time success rates.  upon reduction, the discomfort typically subsides fully but Tylenol may be supplied for ache relief.<14>

Olecranon Bursitis occurs when there is trauma or prolonged pressure to the olecranon bursa.  Bursitis can affect any bursa in the body and is quite common.  The olecranon bursa is recognized to be among the most commonly impacted bursae in the human body.  The olecranon bursa is superficial, lying just underneath the skin and rests top top the triceps tendon and also olecranon.  Olecranon bursitis may likewise sometimes be referred to as student’s elbow.  prolonged pressure ~ above the elbows such together in instances where a college student leans ~ above their elbow for lengthy periods that time, may cause inflammation that the olecranon bursa.  Olecranon bursitis may also idiopathic or septic. Septic bursitis is most often caused through trauma. The best means to diagnose a septic bursitis is aspiration and society of bursal fluid.  therapy of olecranon bursitis is initially conservative, with NSAID’s, rest, compression, ice, and needle aspiration, which can be both therapeutic and also diagnostic. If conservative management fails, operative treatment may be necessary.  Olecranon bursectomy is scheduled for chronic instances that interfere through function.

See more: How To Use Iron Doors In Minecraft, How Do You Lock An Iron Door In Minecraft

<15>

Elbow dislocations occur much more frequently in athletes than in the general population, and also the elbow is the second most dislocated huge joint after the shoulder. Simple dislocations must be treated early with range-of-motion exercises and return to the sport, even with high-level athletes.  patient who experience post-injury instability or have more facility dislocations where fracture or ligamentous damages occurs might require surgery. Posterior elbow dislocations frequently are the many severe, resulting in an ext ligamentous damage. If a patient experiences a dislocated elbow, it is recommended to achieve both AP and also lateral radiographs before and also after reducing the joint uneven there is neurovascular compromise noted.  that said, a dislocated elbow need to be reduced as shortly as possible.<1>


Other Issues

Elbow injuries are an extremely prominent in athletics. Together a result, there is a constant impetus because that ways by which to increase the strength and also stability the this joint.