what is joint presentation

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INTRODUCTION

The major clinical features of RA, including the articular manifestations, are reviewed here. The systemic and extraarticular features and the diagnosis and differential diagnosis of RA are discussed in detail separately. (See "Overview of the systemic and nonarticular manifestations of rheumatoid arthritis" and "Diagnosis and differential diagnosis of rheumatoid arthritis" .)

INITIAL CLINICAL PRESENTATION

The symptoms of RA can affect patients' capacity to perform the activities of daily living (eg, walking, stairs, dressing, use of a toilet, getting up from a chair, opening jars, doors, typing) and those required in their occupation.

Systemic symptoms may also be present in these patients, particularly those with disease onset after age 60 (historically termed "elderly-onset RA"); in up to one-third of patients, the acute onset of polyarthritis is associated with prominent myalgia, fatigue, low-grade fever, weight loss, and depression. Less often, extraarticular manifestations such as nodules or episcleritis may also be present. (See 'Extraarticular involvement' below.)

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Sharing the stage – tips for presenting with other people.

It’s surprising how often people present in pairs on stage, or set up panels, or group shows of one kind or another.  It’s also surprising how often people miss some simple ways to make the experience more engaging and more delightful for the audience and themselves.  All too often, everyone just does their own thing – serial presentations, rather than taking advantage of the fun that adding more people offers.  Following are some quick tips for looking like pros who do joint presenting all the time. 

1. The audience cares about how you relate to one another, so show them.  As soon as you get more than one person on stage, you have the potential for drama, and the audience wants to know, how do these people feel about each other?  What’s their relationship?  Let’s see some banter, or at the very least, some by-talk.  Tell us what you two, or more, have in common, or do together, or feel about each other, and if at all possible, make it fun.  

2.  Introduce each other; don’t introduce yourselves.  Come on, everyone knows it’s hard to introduce yourself.  It’s much, much easier for someone else to talk about how great you are.  And much more believable.  And yet how many panels have you seen where the host asks everyone to begin by introducing themselves?  Lazy, poor form, and hard work for the audience to get through.  If you’re leading a panel discussion, either introduce everyone, or get people to introduce each other.  Having to start by talking about oneself makes most people uncomfortable; why start out uncomfortably?

3.  Appoint an MC; preferably one who is comfortable playing the role.   The MC should think of herself as the audience’s advocate, helping them through the day, putting learning together, summarizing, analyzing, doing the hard work of making sense of what the audience is hearing.

4.  Look interested when a colleague is speaking.   This is a particular pet peeve of mine.  If someone else on your team is talking, pay attention.  Look interested.  In fact, look like it’s the most interesting thing you’ve ever heard.  It’s the height of arrogance and un-team-like behavior to do something distracting when another teammate is presenting.  Don’t do it.  Ever.  Look interested – and be ready to help if something goes wrong. 

5.  If you’re presenting something technical, or a demo, be prepared for things to go wrong, and get help.     Demos are the Devil’s children.  When they go well – a rare occurrence – they’re quite impressive.  But usually Satan is in the room and something goes wrong.  Then it’s important to have a Plan B, a co-presenter to talk through things, and support from the team.  The best approach is always to be real.  Don’t think of it as an error, but rather an opportunity.  Explain what’s going on, don’t try to hide it. 

6.  Rehearse the hand-offs and transitions.  Rehearse them again.  All too often, people rehearse their own stuff and forget about the handoffs.  And that’s where the problems and awkwardness therefore inevitably show up.  It’s harder than it looks!  Practice handoffs!  If you’re under-rehearsed, and you will be, then consider talking yourself and your audience through it out loud, rather than trying to make it look cool.  In other words, say something like, “We’re almost done here, and now Francis is going to come on stage and talk about next steps.”  That approach has the added benefit of cuing Francis in case he’s lost somewhere in the script.

7.  Don’t hog the limelight.  But do stand up to speak.   If you’re presenting as a team, give everyone a chance to shine.  Don’t let one superstar do all the talking.  That’s not teamwork.  But do stand up to speak; the tallest person in the room commands the attention and authority, so if everyone is sitting, it’s a simple way for the speaker to be the center of attention while he is speaking. 

Finally, mix things up.  Don’t do all the panels the same way or have an endless series of 20-minute talks just because you want to imitate the TEDx format.  Variety is extremely helpful for an audience to remember more of the information coming at them during the day because variety is interesting.  Always remember that sitting in a hotel meeting room is like a sensory deprivation chamber – typically there are no windows, there’s a background roar from the A/C system, the lighting is bad, and there’s little for an audience to do except sit.  Every way that you manage to change that experience up will be wonderful and invigorating for the audience.   

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About the author: nick morgan.

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Good morning Nick

As always a message of audience first and have fun. I came across this quote the other day which I really liked.

“Not until human nature is other than what it is, will the function of the living voice-the greatest force on earth among men- cease. . .

I advocate, therefore, in its full extent, and for every reason of humanity, of patriotism, and of religion, a more through culture of oratory and

I define oratory to be art of influencing conduct with the truth set home by all the resources of the living man.” -Henry Ward Beecher

A bit of gender balance “among men and women” but I really liked “influencing conduct with the truth,” that would be a new experience for some.

And I loved the Utopian “culture of oratory”.

Thank you as always.

Kindest regards John

John, speed the day when we (once again) have a “culture of oratory”! It will be a better world, I have no doubt.

Nick, another excellent column. I especially love idea number 2, and think it’s a brilliant twist on the usual slog thru intros. All of this applies so beautifully to the work I do with my CIO events — You can be sure I’ll be sending links to your column to many of my speakers in the future! Years ago I wrote a column with10 points each on being a great panelist or a great moderator. I’ll send that along to you for your amusement. :) Fondly as always, Maryfran

Thanks, Maryfran — I remember your CIO events with fondness, and am delighted to think I could help improve them (in a small way, since they were already great). I’ll look forward to your column.

Good morning Nick – I am having a problem with your email, the one I have used in the past, but keeps failing.

This is my message

Road Manager reporting in. I will meet you at your hotel 10am on Tuesday morning. We take a short stroll, weather permitting, have a coffee and then our first place to visit is at 11.30am.

This is a place, I feel, you will find very interesting and requires smart casual attire. I have invited a special friend to come along, hopes to make it for 11.30 and if not, we will catch up later. Lunch.

After that Guinness and after we have choices.

I sincerely hope you are very happy with the clarity of my planning.

It is interesting our connection from the virtual world, to face-to-face meeting, to a sense of friendship.

It follows your book in many ways, you send out highly engaging content, I throw in my penny’s worth, you reply, connection is made, face-to-face, friendship.

John, I’m in! Use the following email: [email protected]

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Johns Hopkins Arthritis Center

Osteoarthritis: Epidemiology & Risk Factors

Epidemiology.

OA is the most common type of arthritis. Reported incidence and prevalence rates of OA in specific joints vary widely, due to differences in the case definition of OA. OA may be defined by radiographic criteria alone (radiographic OA), typical symptoms (symptomatic OA), or by both. Using radiographic criteria, the distal and proximal interphalangeal joints of the hand have been identified as the joints most commonly affected by OA, but they are the least likely to be symptomatic. In contrast, the knee and hip, which constitute the second and third most common locations of radiographic OA, respectively, are nearly always symptomatic. The first metatarsal phalangeal and carpometacarpal joints are also frequent sites of radiographic OA, while the shoulder, elbow, wrist and metacarpophalangeal joints rarely develop idiopathic OA.

Risk Factors for Osteoarthritis

• AGE: In demographic studies, age is the most consistently identified risk factor for OA, regardless of the joint being studied. Prevalence rates for both radiographic OA and, to a lesser extent, symptomatic OA rise steeply after age 50 in men and age 40 in women. OA is rarely present in individuals less than 35 years of age, and secondary causes of OA or other types of arthritis should strongly be considered in this population.
• SEX: Female gender is also a well-recognized risk factor for OA. Hand OA is particularly prevalent among women. In addition, polyarticular OA and isolated knee OA are slightly more common in women than men, while hip OA occurs more commonly in men. Interestingly, women are more likely to report pain in all affected joints, including the hip, than men.
• OBESITY: Cohort studies have demonstrated a clear association of obesity with the development of radiographic knee OA in women and a weaker association with hip OA. Whether obesity is a risk factor for the development of hand OA remains controversial. Regardless, this remains one of the most important modifiable   risk factors for OA and patients should be counseled appropriately.
• JOINT STRESS: Occupation-related repetitive injury and physical trauma contribute to the development of secondary (non-idiopathic) OA, sometimes occurring in joints that are not affected by primary (idiopathic) OA, such as the metacarpophalangeal joints, wrists and ankles. Although the prevalence of knee OA is greater in adults who have engaged in occupations that require repetitive bending and strenuous activities, an association with regular, intense exercise remains controversial. While early studies in joggers failed to find a higher prevalence of OA of the knee in joggers compared to non-joggers, a recent study of the Framingham data base in elderly adults provided the first longitudinal association between high level of physical activity and incident knee OA. Low-impact and recreational exercises are unlikely to constitute a risk factor for knee OA, and are likely to benefit the cardiovascular system. Prior menisectomy is a significant risk factor in men for the development of OA in the knee.
• GENETICS:  Twin studies have demonstrated an important role for genetics in the development of OA. In some cases, this is associated with a particular genetic syndrome, such as Stickler syndrome or familial chondrocalcinosis. Genome-wide studies contiue to evaluate for particular chromosomes, particularly those involved in bone or articular cartilage structure and metabolism, and associations of familial OA.

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Chapter 27-1:  Approach to the Patient with Joint Pain - Case 1

Adam S. Cifu

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Chief complaint, constructing a differential diagnosis.

• RANKING THE DIFFERENTIAL DIAGNOSIS
• MAKING A DIAGNOSIS
• CASE RESOLUTION
• Full Chapter
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Mrs. K is a 75-year-old woman who complains of a painful left knee.

Figure 27-1.

Diagnostic approach: joint pain.

The causes of joint pain range from common to rare and from bothersome to life-threatening. Even the most benign causes of joint pain can lead to serious disability. The evaluation of a patient with joint pain calls for a detailed history and physical exam (often focusing on extra-articular findings) and occasionally the analysis of joint fluid, serologies, and radiologic tests.

The differential diagnosis of joint pain can be framed with the use of 3 pivotal questions. First, is a single joint or are multiple joints involved (is the joint pain monoarticular or polyarticular)? If the pain involves just 1 joint, the next question is, is the pain monoarticular or extra-articular? Although this distinction may seem obvious, abnormalities of periarticular structures can mimic articular disease. Finally, are the involved joints inflamed or not? Further down the differential, the acuity of the pain may also be important.

Figure 27-1 shows a useful algorithm organized according to these pivotal points. Because periarticular joint pain is almost always monoarticular, the first pivotal point differentiates monoarticular from polyarticular pain. Periarticular syndromes are discussed briefly at the end of the chapter.

The differential diagnosis below is organized by these 3 pivotal points as well. When considering both the algorithm and the differential diagnosis, recognize that all of the monoarticular arthritides can present in a polyarticular distribution, and classically polyarticular diseases may occasionally only affect a single joint. Thus, this organization is useful to organize your thinking but should never be used to exclude diagnoses from consideration.

Monoarticular arthritis

Inflammatory

Nongonococcal septic arthritis

Gonococcal arthritis

Lyme disease

Crystalline

Monosodium urate (gout)

Calcium pyrophosphate dihydrate deposition disease (CPPD or pseudogout)

Noninflammatory

Osteoarthritis (OA)

Avascular necrosis

Polyarticular arthritis

Rheumatologic

Rheumatoid arthritis (RA)

Systemic lupus erythematosus (SLE)

Psoriatic arthritis

Other rheumatic diseases

Bacterial endocarditis

Hepatitis B

Postinfectious

Rheumatic fever

Noninflammatory: OA

Mrs. K’s symptoms started after she stepped down from a bus with unusual force. The pain became intolerable within about 6 hours of onset and has been present for 3 days now. She otherwise feels well. She reports no fevers, chills, dietary changes, or sick contacts.

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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

StatPearls [Internet].

Anatomy, joints.

Pallavi Juneja ; Akul Munjal ; John B. Hubbard .

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Last Update: December 9, 2023 .

• Introduction

A joint is a point where two bones make contact. Joints can be classified either histologically or functionally. Histological classification is based on the dominant type of connective tissue, and functional classification is based on the amount of movement permitted. Histologically the three joints in the body are fibrous, cartilaginous, and synovial. Functionally the three types of joints are synarthrosis (immovable), amphiarthrosis (slightly moveable), and diarthrosis (freely moveable). The two classification schemes can be correlated: synarthroses are fibrous, amphiarthroses are cartilaginous, and diarthroses are synovial. [1] [2]

Joints, comprising bones and connective tissue, are embryologically derived from mesenchyme. The bones either develop directly through intramembranous ossification or indirectly through endochondral ossification. Each specific joint has a unique vascular supply and innervation scheme; patterns do exist. Muscles provide stability to joints, and there is a direct correlation between muscle strength and joint stability, particularly with synovial joints.

Many pathophysiological conditions affect joints, and again, patterns exist by histological class. Because diseases that affect the joints are common across the lifespan, a thorough understanding of joint structure and function is of great clinical significance.

• Structure and Function

The histological and functional classification schemes offer a broad understanding of joints. As aforementioned, histological classification is based on the dominant type of connective tissue, and functional classification is based on the amount of movement permitted. 

Histologically the three joints in the body are fibrous, cartilaginous, and synovial. Functionally the three types of joints are synarthrosis (immovable), amphiarthrosis (slightly moveable), and diarthrosis (freely moveable). The two classification schemes can be correlated: synarthroses are fibrous, amphiarthroses are cartilaginous, and diarthroses are synovial. [1] [2]

Within these categories, each specific joint type (suture, gomphosis, syndesmosis, synchondrosis, symphysis, hinge, saddle, planar, pivot, condyloid, ball, and socket) has a specific function in the body.

Fibrous Joints

A fibrous joint is a fixed joint where collagenous fibrous connective tissue connects two bones. Fibrous joints (synarthroses) are usually immovable and have no joint cavity. They are subdivided further into sutures, gomphoses, and syndesmoses.

Sutures are immobile joints found only in the cranium. The plate-like bones of the skull are slightly mobile at birth because of the connective tissue between them. The spaces between the bones are termed fontanelles. This initial joint flexibility allows the fetal head to pass through the birth canal at delivery and permits brain enlargement after birth. As the skull enlarges, the fontanelles reduce to a narrow layer of fibrous connective sutures that suture the bony plates together. This connective tissue is termed Sharpey fibers. Eventually, cranial sutures ossify. Finally, the two adjacent plates fuse to form one bone; this fusion is termed synostosis.

Gomphoses are the immobile joints found only between the teeth and their sockets in the mandible and maxillae. The periodontal ligament is the fibrous tissue that connects the tooth to the socket.

Syndesmoses are slightly movable joints (amphiarthroses). This type of fibrous joint maintains integrity between long bones and resists forces that attempt to separate the two bones. All syndesmoses are amphiarthroses, but each specific syndesmosis joint permits a different degree of movement. For example, the tibiofibular syndesmosis primarily provides strength and stability to the leg and ankle during weight-bearing; however, the antebrachial interosseous membrane of the radioulnar syndesmosis permits rotation of the radius bone during forearm movements. The interosseous membranes of the leg and forearm are also areas of muscle attachment. [3]

Cartilaginous Joints

In cartilaginous joints, the bones attach by hyaline cartilage or fibrocartilage. Depending on the type of cartilage involved, the joints are further classified as primary or secondary cartilaginous joints.

A synchondrosis, or primary cartilaginous joint, only involves hyaline cartilage and can be temporary or permanent. 

A temporary synchondrosis is an epiphyseal plate (growth plate). It functions to permit bone lengthening during development. The epiphyseal plate connects the diaphysis (shaft of the bone) with the epiphysis (end of the bone) in children. Over time, the cartilaginous plate expands and is replaced by bone, adding to the diaphysis. Eventually, when all the hyaline cartilage has ossified, the bone has completed its lengthening, and the diaphysis and epiphysis fuse in synostosis. Other temporary synchondroses join the ilium, ischium, and pubic bones of the hip. Over time, these also fuse into a single hip bone.  

A permanent synchondrosis does not ossify with age; it retains its hyaline cartilage. Permanent synchondroses function to connect bones without movement as a synarthrosis joint. Examples are found in the thoracic cage, such as the first sternocostal joint: the first rib is joined to the manubrium by its costal cartilage. Other examples include the relationship between the anterior end of the other 11 ribs and the costal cartilage. [4]

A symphysis, or secondary cartilaginous joint, involves fibrocartilage. Fibrocartilage is thick and strong, so symphyses have a remarkable ability to resist pulling and bending forces. While the fibrocartilage firmly unites adjacent bones, the joint is still an amphiarthrosis joint and permits limited movement. 

A symphysis can be narrow or wide. Narrow symphyses include the pubic symphysis and the manubriosternal joint. In females, the slight mobility of the pubic symphysis between the left and right pubic bones is critical for childbirth. A wider example of a symphysis is the intervertebral symphysis or intervertebral disc. The thick pad of fibrocartilage fills the gap between adjacent vertebrae and provides cushioning during high-impact activity.

Synovial Joints

Synovial joints (diarthroses) are freely mobile and are considered the main functional joints of the body. The synovial joint is characterized by the presence of a joint cavity. The primary purpose of the synovial joint is to prevent friction between the articulating bones of the joint cavity. The joint cavity is surrounded by the articular capsule, a fibrous connective tissue attached to each participating bone just beyond its articulating surface. The joint cavity contains synovial fluid secreted by the synovial membrane (synovium), which lines the articular capsule. Hyaline cartilage forms the articular cartilage, covering the entire articulating surface of each bone. The articular cartilage and the synovial membrane are continuous. Some synovial joints also have associated fibrocartilage between articulating bones. An example of this is the menisci of the knee.

While all synovial joints are diarthroses, the extent of movement varies among different subtypes and is often limited by the ligaments that connect the bones. Therefore, synovial joints are often further classified by the type of movements they permit. There are six such classifications: hinge (elbow), saddle (carpometacarpal joint), planar (acromioclavicular joint), pivot (atlantoaxial joint), condyloid (metacarpophalangeal joint), and ball and socket (hip joint).

Synovial Joint: Hinge

A hinge joint is an articulation between the convex end of one bone and the concave end of another. This type of joint is uniaxial because it only permits movement along one axis. In the body, this axis of movement is usually flexion and extension (bending or straightening). Examples include the elbow, knee, ankle, and interphalangeal joints. 

Synovial: Condyloid

A condyloid joint, or an ellipsoid joint, is an articulation between the shallow depression of one bone and the rounded structure of one or more other bones. This type of joint is biaxial because it permits two axes of movement: flexion/extension and medial/lateral (abduction/adduction). An example is the metacarpophalangeal joints of the hand between the distal metacarpal and proximal phalanx, commonly known as the knuckle. 

Synovial Joint: Saddle

A saddle joint is an articulation between two bones that are saddle-shaped - concave in one direction and convex in another. This type of joint is biaxial. One example is the first carpometacarpal joint between the trapezium (carpal) and the first metacarpal bone of the thumb. This arrangement permits the thumb to flex and extend (within the plane of the palm) as well as abduct and adduct (perpendicular to the palm). This dexterity gives humans the characteristic trait of “opposable” thumbs. The opposable thumb is critical for the complex motions involved in the use of the hand. Loss of the thumb by any mechanism severely limits the utility of the hand.

Synovial Joint: Planar

A planar joint, or gliding joint, is defined as an articulation between two bones that are both flat and of similar size. This type of joint is multiaxial because it permits many movements; however, surrounding ligaments usually restrict this joint to a small and tight motion. Examples include intercarpal joints, intertarsal joints, and the acromioclavicular joint.

Synovial Joint: Pivot

A pivot joint is an articulation within a ligamentous ring between the rounded end of one bone and another bone. This type of joint is uniaxial because, although the bone rotates within this ring, it does so around a single axis. An example is the atlantoaxial joint between C1 (atlas) and C2 (axis) of the vertebrae. This joint permits side-to-side head motion of the head. Another example is the proximal radioulnar joint. The radius sits in the annular radial ligament, which holds it in place as it articulates with the radial notch of the ulna, which permits pronation and supination.

Synovial Joint: Ball and Socket 

A ball and socket joint is an articulation between the rounded head of one bone (ball) and the concavity of another (socket). This type of joint is multiaxial: it permits flexion/extension, abduction/adduction, and rotation. The only two ball and socket joints of the body are the hips and the shoulder (glenohumeral). The shallow socket of the glenoid cavity permits a more extensive range of motion in the shoulder; the deeper socket of the acetabulum and the supporting ligaments of the hip constrain the movement of the femur.

Joints, comprising bones and connective tissue, are embryologically derived from mesenchyme. The bones either develop directly through intramembranous ossification or indirectly through endochondral ossification. During direct development, the mesenchymal cells differentiate into bone-producing cells. During indirect development, the mesenchymal cells first differentiate into hyaline cartilage that is gradually displaced by bone. The connective tissue of the joint arises from the mesenchymal cells between the developing bones.

For the synovial joints of the limbs, the space between the developing long bones is termed the joint interzone. The interzone becomes apparent in the sixth week of embryonic development when a cellular condensation of mesoderm on either side, termed the paraxial blastema, chondrifies into hyaline cartilage models for the long bones. In the eighth week of embryonic development, mesenchymal cells at the margin of the interzone become the articular capsule; cell death in the center forms the joint cavity, which is filled with synovial fluid produced by mesenchymal cells. The articular cartilage is a remnant of the hyaline cartilage that, between gestational weeks 6 and 8, became the long bones via endochondral ossification. [5] [6]

• Blood Supply and Lymphatics

Every joint has a different blood supply; however, there are patterns based on the histological classification of joints.

Fibrous joints are usually supplied by perforating branches of the proximal vessels. For example, the blood supply of the tibiofibular joint is derived from branches of the anterior tibial artery and the peroneal (fibular) artery.

Cartilaginous joints only receive their vascular supply at the periphery because cartilage is an avascular tissue. Intervertebral discs, for example, are supplied at the margins by capillaries from the vertebral bodies.

Synovial joints receive vascular supply through a rich anastomosis of arteries extending from either side of the joint, termed the periarticular plexus. Some vessels penetrate the fibrous capsule to form a rich plexus deeper in the synovial membrane. This deeper plexus, the circulus vasculosus, forms a loop around the articular margins that supplies the articular capsule, synovial membrane, and terminal bone. The articular cartilage, which is avascular hyaline cartilage, is nourished by the synovial fluid.

Lymphatic vessels for every joint follow the lymph drainage of the surrounding tissue; some joints house lymph nodes, like the popliteal lymph nodes in the popliteal fossa of the knee.

Every joint in the body has different innervation; however, the innervation of synovial joints is most extensively understood. 

Sensory and autonomic fibers innervate synovial joints. The autonomic nerves are vasomotor in function, controlling the dilation or constriction of blood vessels through the actions of norepinephrine and epinephrine. These sympathetic nervous system fibers use alpha-1 adrenergic receptors to cause the arteriolar vascular smooth muscle to contract. The sensory nerves of the articular capsule and ligaments (articular nerves) provide proprioceptive feedback from Ruffini endings and Pacinian corpuscles. Proprioception of the joint permits reflex control of posture, locomotion, and movement. Free nerve endings convey pain sensation that is diffuse and poorly localized. The articular cartilage has no nerve supply. 

Two general principles apply to synovial joint innervation: the Hilton law and the Gardner observation. The Hilton law states that the articular nerves supplying a joint are branches of the nerves that supply the muscles responsible for moving that joint. Therefore, irritation of articular nerves causes a reflex spasm of the muscles, which position the joint for the greatest comfort. These nerves also supply the overlying skin, providing a mechanism for referred pain from joint to skin. The Gardner observation indicates that the part of the articular capsule that is tightened by contraction of a group of muscles receives nerve supply from the same nerves that innervate the antagonist muscles. This relationship provides local reflex arcs that stabilize the joint. [7]

Muscles are most critical in providing additional support for synovial joints. The muscles and their tendons which cross a joint resist the forces acting on that joint, behaving as a dynamic "ligament." Muscle strength is, therefore, essential to the stability of synovial joints, especially during high-stress activity, as well as for joints with weaker ligaments, for example, the glenohumeral joint.

• Surgical Considerations

The surgical replacement of joints is possible using an operation called an arthroplasty; this procedure treats chronic pain and limited mobility associated with osteoarthritis. However, arthroplasty is an invasive procedure, so it is the last line of treatment. The operation removes the damaged bone and replaces the articular surfaces with an artificial metal, plastic, or ceramic device (prosthesis) built to mimic the natural structure of the joint. Hips and knees are the most commonly replaced joints.

• Clinical Significance

Different pathologic conditions are associated with different joint types. Below is a review of the most common injuries that plague each histological class. 

Sutures, the immobile fibrous joints that bind the bony plates of the skull, can fuse too early in development, a condition termed craniosynostosis. The plates of the neonatal skull are not fused so as to permit space for the brain to grow in all planes; early fusion (synostosis) alters the shape of the head. For example, if the sagittal suture synostoses, the head will not develop width and will instead grow long and narrow (scaphocephaly). In addition to altered head shape, some children may experience symptoms secondary to high brain pressure due to more confined skull space. These include headaches, developmental delays, or problems with eyesight. [8]

A syndesmosis joint, the slightly mobile fibrous joint that connects long bones with an interosseous membrane, can be sprained. For example, in the leg, excessive external rotation can push the fibula away from the tibia, causing injury to the distal tibiofibular syndesmosis; this is termed a “high ankle sprain.”  [9] [3]

Epiphyseal plates, an example of temporary synchondroses, are vulnerable to damage when there is an injury to the associated growing long bone. Such damage to the cartilage would stop bone lengthening and stunt bone growth.

Arthritis results in the destruction of the synovial joint. There are many types of arthritis, distinguished by different mechanisms of injury. The most common type of arthritis is osteoarthritis, which, by definition, is gradual damage to and subsequent thinning of the articular cartilage. This condition is considered a “wear and tear” injury and presents in older patients; it often correlates with prior injury to the joint and longstanding high-impact stress on the joint (due to sports or excessive body weight). Because the articular cartilage has no innervation, the degradation itself does not cause pain. Instead, as the articular cartilage becomes thinner, more pressure is placed on the bones. The joint responds by overproducing synovial fluid, which leads to swelling and inflammation that stretches the highly innervated articular capsule to cause pain and stiffness of the joint. The underlying bone also has a rich nerve supply that perceives pain.

Gout is another form of arthritis caused by the deposition of uric acid crystals within a joint. Uric acid causes gout when there is an excessive amount in the body, either due to over-production or improper excretion by the kidneys. The most commonly affected joint is the metatarsophalangeal (MTP) joint of the big toe. This condition is termed podagra. [10] [11] [12]  Patients often present with excruciating pain and swelling. [13]  The consumption of alcohol may exacerbate podagra. [14] [15] [16]

Synovitis is inflammation of the synovial membrane that lines the articular capsule of synovial joints. The most common cause is the overuse of a synovial joint in an active, healthy person. Persistent synovitis in multiple joints can indicate rheumatoid arthritis, where the synovium is the target of the autoimmune attack. Patients with synovitis often present with pain out of proportion to examination; sometimes, the patient has pain without swelling or tenderness, or arthralgia.

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Joint Anatomy. Image includes cartilage, perichondrium, and periosteum. Gray's Anatomy

Treatise on dislocation and on fracture of the joints, dislocations, fractures, bone, joints, Figure 1 shows dislocation of the scapular end of the clavicle upon the acromion; clavicle is seen projecting over the spine of the scapula, ligament Contributed (more...)

Foot joints Image courtesy S Bhimji MD

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• Cite this Page Juneja P, Munjal A, Hubbard JB. Anatomy, Joints. [Updated 2023 Dec 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

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9.1 Classification of Joints

Learning objectives.

By the end of this section, you will be able to:

Discuss both functional and structural classifications for body joints

• Distinguish between the functional and structural classifications for joints
• Describe the three functional types of joints and give an example of each
• Describe the three structural types of joints and give an example of each
• Describe the planes of movement possible in diarthrodial joints

A joint , also called an articulation , is any place where adjacent bones or bone and cartilage come together (articulate with each other) to form a connection. Joints are classified both structurally and functionally. Structural classifications of joints take into account whether the adjacent bones are strongly anchored to each other by fibrous connective tissue or cartilage, or whether the adjacent bones articulate with each other within a fluid-filled space called a joint cavity . Functional classifications describe the degree of movement available between the bones, ranging from immobile, to slightly mobile, to freely moveable joints. The amount of movement available at a particular joint of the body is related to the functional requirements for that joint. Thus immobile or slightly moveable joints serve to protect internal organs, give stability to the body, and allow for limited body movement. In contrast, freely moveable joints allow for much more extensive movements of the body and limbs.

Structural Classification of Joints

The structural classification of joints is based on whether the articulating surfaces of the adjacent bones are directly connected by fibrous connective tissue or cartilage, or whether the articulating surfaces contact each other within a fluid-filled joint cavity. These differences serve to divide the joints of the body into three structural classifications. A fibrous joint is where the adjacent bones are united by fibrous connective tissue. At a cartilaginous joint , the bones are joined by hyaline cartilage or fibrocartilage. At a synovial joint , the articulating surfaces of the bones are not directly connected, but instead come into contact with each other within a joint cavity that is filled with a lubricating fluid. Synovial joints allow for free movement between the bones and are the most common joints of the body.

Functional Classification of Joints

The functional classification of joints is determined by the amount of mobility found between the adjacent bones. Joints are thus functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, which is a freely moveable joint (arthroun = “to fasten by a joint”). Depending on their location, fibrous joints may be functionally classified as a synarthrosis (immobile joint) or an amphiarthrosis (slightly mobile joint). Cartilaginous joints are also functionally classified as either a synarthrosis or an amphiarthrosis joint. All synovial joints are functionally classified as a diarthrosis joint.

Synarthrosis

An immobile or nearly immobile joint is called a synarthrosis (plural = synarthroses). The immobile nature of these joints provide for a strong union between the articulating bones. This is important at locations where the bones provide protection for internal organs. Examples include sutures, the fibrous joints between the bones of the skull that surround and protect the brain ( Figure 9.1.1 ), and the epiphyseal growth plate, a cartilaginous joint that unites the epiphyses and diaphysis of a growing long bone like the femur.

Amphiarthrosis

An amphiarthrosis (plural = amphiarthroses) is a joint that has limited mobility. An example of this type of joint is the cartilaginous joint that unites the bodies of adjacent vertebrae. Filling the gap between the vertebrae is a thick pad of fibrocartilage called an intervertebral disc ( Figure 9.1.2 ). Each intervertebral disc strongly unites the vertebrae but still allows for a limited amount of movement between them. However, the small movements available between adjacent vertebrae can sum together along the length of the vertebral column to provide for large ranges of body movements.

Another example of an amphiarthrosis is the pubic symphysis of the pelvis. This is a cartilaginous joint in which the pubic regions of the right and left hip bones are strongly anchored to each other by fibrocartilage. This joint normally has very little mobility. The strength of the pubic symphysis is important in conferring weight-bearing stability to the pelvis. During pregnancy, increased levels of the hormone relaxin lead to increased mobility at the pubic symphysis which allows for expansion of the pelvic cavity during childbirth.

Diarthrosis

A freely mobile joint is classified as a diarthrosis  (plural = diarthroses). This functional classification of joints describes all synovial joints of the body, which provide the majority of body movements. Most diarthrotic joints are found in the appendicular skeleton and give the limbs a wide range of motion. These joints are divided into three categories, based on the number of axes of motion provided by each. An axis in anatomy is described as the movements in reference to the three anatomical planes: transverse, frontal, and sagittal. Thus, diarthroses are classified as uniaxial, biaxial, or multiaxial joints.

A uniaxial joint only allows for a motion in a single plane (around a single axis). The elbow joint, which only allows for bending or straightening, is an example of a uniaxial joint. A biaxial joint allows for motions within two planes. An example of a biaxial joint is a metacarpophalangeal joint (knuckle joint) of the hand. The joint allows for movement along one axis to produce bending or straightening of the finger, and movement along a second axis, which allows for spreading of the fingers away from each other and bringing them together. A joint that allows for the several directions of movement is called a multiaxial joint (sometimes called polyaxial or triaxial joint). This type of diarthrotic joint allows for movement along three axes ( Figure 9.1.3 ). The shoulder and hip joints are multiaxial joints. They allow the upper or lower limb to move in an anterior-posterior direction and a medial-lateral direction. In addition, the limb can also be rotated around its long axis. This third movement results in rotation of the limb so that its anterior surface is moved either toward or away from the midline of the body.

Chapter Review

Structural classifications of the body joints are based on how the bones are held together and articulate with each other. At fibrous joints, the adjacent bones are directly united to each other by fibrous connective tissue. Similarly, at a cartilaginous joint, the adjacent bones are united by cartilage. In contrast, at a synovial joint, the articulating bone surfaces are not directly united to each other, but come together at a fluid-filled joint cavity.

The functional classification of body joints is based on the degree of movement found at each joint. A synarthrosis is a joint that is essentially immobile. This type of joint provides for a strong connection between the adjacent bones, which serves to protect internal structures such as the brain or heart. Examples include the fibrous joints of the skull sutures and the cartilaginous epiphyseal plate. A joint that allows for limited movement is an amphiarthrosis. An example is the pubic symphysis of the pelvis, the cartilaginous joint that strongly unites the right and left hip bones of the pelvis. The cartilaginous joints in which vertebrae are united by intervertebral discs provide for small movements between the adjacent vertebrae and are also amphiarthrotic joints. Thus, based on their movement ability, some fibrous and cartilaginous joints are functionally classified as synarthroses while others are amphiarthroses.

The most common type of joint is the diarthrosis, which is a freely moveable joint. All synovial joints are functionally classified as diarthroses. A uniaxial diarthrosis, such as the elbow, is a joint that only allows for movement within a single anatomical plane. Joints that allow for movements in two planes are biaxial joints, such as the metacarpophalangeal joints of the fingers. A multiaxial joint, such as the shoulder or hip joint, allows for three planes of motions.

Review Questions

Critical thinking questions.

1. Define how joints are classified based on function. Describe and give an example for each functional type of joint.

2. Explain how degree of mobility is related to joint strength.

Answers for Critical Thinking Questions

• Functional classification of joints is based on the degree of mobility exhibited by the joint. A synarthrosis is an immobile or nearly immobile joint. An example is the epiphyseal plate or the joints between the skull bones surrounding the brain. An amphiarthrosis is a slightly moveable joint, such as the pubic symphysis or an intervertebral cartilaginous joint. A diarthrosis is a freely moveable joint. These are subdivided into three categories. A uniaxial diarthrosis allows movement within a single anatomical plane or axis of motion. The elbow joint is an example. A biaxial diarthrosis, such as the metacarpophalangeal joint, allows for movement along two planes or axes. The hip and shoulder joints are examples of a multiaxial diarthrosis. These allow movements along three planes or axes.
• Joint mobility is inversely related to joint strength. A synarthrosis, which is an immobile joint, serves to strongly connect bones thus protecting internal organs such as the heart or brain. A slightly moveable amphiarthrosis provides for small movements while maintaining stability between adjacent bones as in the vertebral column. The freedom of movement provided by a diarthrosis can allow for large movements, such as is seen with most joints of the limbs. However, these joints are the most frequently injured due to their looser articulations at the joint cavity.

This work, Anatomy & Physiology, is adapted from Anatomy & Physiology by OpenStax , licensed under CC BY . This edition, with revised content and artwork, is licensed under CC BY-SA except where otherwise noted.

Images, from Anatomy & Physiology by OpenStax , are licensed under CC BY except where otherwise noted.

Access the original for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction .

Anatomy & Physiology Copyright © 2019 by Lindsay M. Biga, Staci Bronson, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Kristen Oja, Devon Quick, Jon Runyeon, OSU OERU, and OpenStax is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License , except where otherwise noted.

• Anatomical Position
• Body Planes
• Terms of Movement
• Terms of Location
• Embryology Terms
• Classification
• Synovial Joint
• Joint Stability
• Skeletal Muscle
• Blood Vessels
• Head and Neck
• Cardiovascular System
• Respiratory System
• Urinary System
• Reproductive System
• Central Nervous System
• Cranial Fossae
• Pterygopalatine Fossa
• Infratemporal Fossa
• Mastoid Fossa
• Frontal Bone
• Sphenoid Bone
• Ethmoid Bone
• Temporal Bone
• Occipital Bone
• Nasal Skeleton
• Cranial Foramina
• Facial Expression
• Extraocular
• Mastication
• Sympathetic Innervation
• Parasympathetic Innervation
• Ophthalmic Nerve
• Maxillary Nerve
• Mandibular Nerve
• Nose and Sinuses
• Salivary Glands
• Oral Cavity
• Arterial Supply
• Venous Drainage
• Lacrimal Gland
• Basal Ganglia
• Pineal Gland
• Pituitary Gland
• Spinal Cord (Grey Matter)
• Medulla Oblongata
• Ascending Tracts
• Descending Tracts
• Visual Pathway
• Auditory Pathway
• Olfactory Nerve (CN I)
• Optic Nerve (CN II)
• Oculomotor Nerve (CN III)
• Trochlear Nerve (CN IV)
• Trigeminal Nerve (CN V)
• Abducens Nerve (CN VI)
• Facial Nerve (CN VII)
• Vestibulocochlear Nerve (CN VIII)
• Glossopharyngeal Nerve (CN IX)
• Vagus Nerve (CN X)
• Accessory Nerve (CN XI)
• Hypoglossal Nerve (CN XII)
• Dural Venous Sinuses
• Cavernous Sinus
• Anterior Triangle
• Posterior Triangle
• Cervical Spine
• Thyroid Gland
• Parathyroid Glands
• Suboccipital
• Suprahyoids
• Infrahyoids
• Phrenic Nerve
• Cervical Plexus
• Fascial Layers
• Tonsils (Waldeyer's Ring)
• Superior Mediastinum
• Anterior Mediastinum
• Middle Mediastinum
• Posterior Mediastinum
• Thoracic Spine
• Thoracic Cage
• Thymus Gland
• Mammary Glands
• Tracheobronchial Tree
• Superior Vena Cava
• Vertebral Column
• Superficial
• Intermediate
• Spinal Cord
• Quadrangular Space
• Triangular Interval
• Triangular Space
• Cubital Fossa
• Ulnar Tunnel
• Extensor Compartments
• Ulnar Canal
• Carpal Tunnel
• Anatomical Snuffbox
• Pectoral Region
• Shoulder Region
• Anterior Forearm
• Posterior Forearm
• Brachial Plexus
• Axillary Nerve
• Musculocutaneous Nerve
• Median Nerve
• Radial Nerve
• Ulnar Nerve
• Acromioclavicular Joint
• Sternoclavicular Joint
• Shoulder Joint
• Elbow Joint
• Radioulnar Joints
• Wrist Joint
• Metacarpophalangeal Joint
• Proximal Interphalangeal Joint
• Extensor Tendon Expansion
• Flexor Pulley System
• Femoral Triangle
• Femoral Canal
• Adductor Canal
• Popliteal Fossa
• Tarsal Tunnel
• Fascia Lata
• Gluteal Region
• Cutaneous Innervation
• Lumbar Plexus
• Sacral Plexus
• Femoral Nerve
• Obturator Nerve
• Sciatic Nerve
• Tibial Nerve
• Common Fibular Nerve
• Superficial Fibular Nerve
• Deep Fibular Nerve
• Tibiofibular Joints
• Ankle Joint
• Subtalar Joint
• Foot Arches
• Walking and Gaits
• Abdominal Cavity
• Calot’s Triangle
• The Peritoneum
• Inguinal Canal
• Hesselbach's Triangle
• Lumbar Spine
• Anterolateral Abdominal Wall
• Posterior Abdominal Wall
• Small Intestine
• Gallbladder
• Adrenal Glands
• Sciatic Foramina
• Pelvic Girdle
• Sacroiliac Joint
• Pelvic Floor
• Urinary Bladder
• Testes and Epididymis
• Spermatic Cord
• Prostate Gland
• Bulbourethral Glands
• Seminal Vesicles
• Fallopian (Uterine) Tubes
• Supporting Ligaments
• Pudendal Nerve
• Female Body
• Female Pelvis
• Male Pelvis
• Cardiovascular
• Gastrointestinal
• Respiratory
• Female Reproductive
• Male Reproductive

The Shoulder (Glenohumeral) Joint

Original Author(s): Oliver Jones Last updated: November 2, 2023 Revisions: 40

• 1.1 Articulating Surfaces
• 1.2 Joint Capsule 
• 1.3 Ligaments
• 2 Movements 
• 3 Mobility and Stability
• 4 Blood Supply
• 5 Innervation
• 6.1 Dislocation of the Shoulder Joint
• 6.2 Rotator Cuff Tendonitis

The shoulder joint (glenohumeral joint) is an articulation between the scapula and the humerus .

It is a ball and socket -type synovial joint, and one of the most mobile joints in the human body.

In this article, we shall look at the anatomy of the shoulder joint – its structure, blood supply, and clinical correlations.

Anatomical Structure

Articulating surfaces.

The shoulder joint is formed by an articulation between the head of the humerus and the glenoid cavity (or fossa) of the scapula. This gives rise to the alternate name for the shoulder joint – the glenohumeral joint.

Like most synovial joints, the articulating surfaces are covered with  hyaline cartilage .

The head of the humerus is much larger than the glenoid fossa, giving the joint a wide range of movement at the cost of instability. To reduce the disproportion in surfaces, the glenoid fossa is deepened by a fibrocartilage rim –  called the glenoid labrum .

Fig 1 – The articulating surfaces of the shoulder joint.

Joint Capsule 

The  joint capsule  is a fibrous sheath which encloses the structures of the joint.

It extends from the  anatomical neck of the humerus to the border or ‘rim’ of the glenoid fossa. The joint capsule is lax – permitting greater mobility (particularly abduction).

The  synovial membrane lines the inner surface of the joint capsule and produces synovial fluid to reduce friction between the articular surfaces.

Ligaments play an important role in stabilising the shoulder joint:

• Glenohumeral ligaments  (superior, middle and inferior) – extend from the humerus to the glenoid fossa, reinforcing the joint capsule. They act to stabilise the anterior aspect of the joint.
• Coracohumeral ligament  – extends from the base of the coracoid process to the greater tubercle of the humerus. It supports the superior part of the joint capsule.
• Transverse humeral ligament  – extends between the two tubercles of the humerus. It holds the tendon of the long head of the biceps in the intertubercular groove.
• Coracoacromial ligament – extends between the acromion and coracoid process of the scapula, forming an arch-like structure over the shoulder joint (coracoacromial arch). This resists superior displacement of the humeral head.

Fig 2 – The ligaments of the shoulder joint. The transverse humeral ligament is not shown on this diagram

A bursa is a sac-like structure containing a small amount of synovial fluid . It functions to decrease friction between tendons, bone, and skin during movement. There are several bursae present in the shoulder joint:

• It reduces friction beneath the deltoid, promoting free motion of the rotator cuff tendons.
• It reduces friction on the tendon during movement at the shoulder joint.

There are other minor bursae present between the tendons of the muscles around the joint.

Fig 3 – The major bursae of the shoulder joint.

The shoulder joint is an extremely mobile joint, with a wide range of movement possible:

• Extension (upper limb backwards in sagittal plane) – posterior deltoid, latissimus dorsi and teres major.
• Flexion (upper limb forwards in sagittal plane) – pectoralis major, anterior deltoid and coracobrachialis. Biceps brachii weakly assists in forward flexion.
• The first 0-15 degrees of abduction is produced by the supraspinatus.
• The middle fibres of the deltoid are responsible for the next 15-90 degrees.
• Past 90 degrees, the scapula needs to be rotated to achieve abduction – that is carried out by the trapezius and serratus anterior.
• Adduction (upper limb towards midline in coronal plane)  – pectoralis major, latissimus dorsi and teres major.
• Internal rotation (rotation towards the midline, so that the thumb is pointing medially)  – subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid.
• External rotation (rotation away from the midline, so that the thumb is pointing laterally)  – infraspinatus and teres minor.
• Circumduction (moving the upper limb in a circle)  – produced by a combination of the movements described above.

Mobility and Stability

The shoulder joint is one of the most mobile in the body, at the expense of stability. Here, we shall consider the factors the permit movement, and those that contribute towards joint structure.

• Type of joint  – ball and socket joint.
• Bony surfaces – shallow glenoid cavity and large humeral head – there is a 1:4 disproportion in surfaces. A commonly used analogy is the golf ball and tee.
• Joint capsule –  lax
• Rotator cuff muscles  – surround the shoulder joint, attaching to the tuberosities of the humerus, whilst also fusing with the joint capsule. The resting tone of these muscles act to compress the humeral head into the glenoid cavity.
• Glenoid labrum – a fibrocartilaginous ridge surrounding the glenoid cavity. It deepens the cavity and creates a seal with the head of humerus, reducing the risk of dislocation.
• Ligaments – act to reinforce the joint capsule and form the coracoacromial arch.
• Biceps tendon – it acts as a minor humeral head depressor, thereby contributing to stability.

Fig 4 – The rotator cuff muscles, which act to stabilise the shoulder joint.

Blood Supply

The shoulder joint is supplied by the anterior and posterior circumflex humeral arteries – which are both branches of the axillary artery.

There are also contributions from the suprascapular artery (itself a branch of the thyrocervical trunk).

Innervation

Sensory innervation to the shoulder joint is from the axillary and suprascapular  nerves.

Clinical Relevance: Common Injuries

Dislocation of the shoulder joint.

Clinically, dislocations at the shoulder are described by where the humeral head lies in relation to the  glenoid fossa . Anterior dislocations are the most prevalent (95%), although posterior (4%) and inferior (1%) dislocations can sometimes occur. Superior displacement of the humeral head is generally prevented by the coraco-acromial arch .

An anterior dislocation is usually caused by excessive  extension  and  lateral rotation  of the  humerus . The humeral head is forced anteriorly and inferiorly – into the weakest part of the joint capsule. Tearing of the joint capsule is associated with an increased risk of future dislocations. Hill-Sachs lesions (impaction fracture of posterolateral humeral head against anteroinferior glenoid) and Bankart lesions (detachment of antero-inferior labrum with or without an avulsion fracture) can also occur following anterior dislocation.

Indeed, so-called ‘reverse Hill-Sachs lesions’ (impaction fracture of anteromedial humeral head) and ‘reverse Bankart lesions’ (detachment of posteroinferior labrum) can be seen in posterior dislocations.

The  axillary nerve  runs in close proximity to the shoulder joint and around the surgical neck of the humerus, and so it can be damaged in the dislocation or with attempted reduction. Injury to the axillary nerve causes paralysis of the deltoid, and loss of sensation over regimental badge area . 

Fig 5 – Anterior dislocation of the shoulder joint.

Rotator Cuff Tendonitis

The rotator cuff  muscles have a very important role in  stabilising  the glenohumeral joint. They are often under heavy strain, and therefore injuries of these muscles are relatively common.

The spectrum of rotator cuff pathology comprises tendinitis, shoulder impingement and sub-acromial bursitis. Tendinitis refers to  inflammation  of the muscle tendons – usually due to overuse.  Over time, this causes  degenerative changes  in the subacromial bursa and the supraspinatus tendon, potentially causing bursitis and impingement.

The characteristic sign of supraspinatus tendinitis is the ‘ painful arc ’ – pain in the middle of abduction between 60-120 degrees, where the affected area comes into contact with the acromion. This sign may also suggest a partial tear of supraspinatus.

In this article, we shall look at the anatomy of the shoulder joint - its structure, blood supply, and clinical correlations.

The head of the humerus is much larger than the glenoid fossa, giving the joint a wide range of movement at the cost of instability. To reduce the disproportion in surfaces, the glenoid fossa is deepened by a fibrocartilage rim -  called the glenoid labrum .

It extends from the  anatomical neck of the humerus to the border or 'rim' of the glenoid fossa. The joint capsule is lax - permitting greater mobility (particularly abduction).

• Coracoacromial ligament - extends between the acromion and coracoid process of the scapula, forming an arch-like structure over the shoulder joint (coracoacromial arch). This resists superior displacement of the humeral head.
• Extension (upper limb backwards in sagittal plane) - posterior deltoid, latissimus dorsi and teres major.
• Flexion (upper limb forwards in sagittal plane) - pectoralis major, anterior deltoid and coracobrachialis. Biceps brachii weakly assists in forward flexion.
• Adduction (upper limb towards midline in coronal plane)  - pectoralis major, latissimus dorsi and teres major.
• Internal rotation (rotation towards the midline, so that the thumb is pointing medially)  - subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid.
• External rotation (rotation away from the midline, so that the thumb is pointing laterally)  - infraspinatus and teres minor.
• Circumduction (moving the upper limb in a circle)  - produced by a combination of the movements described above.
• Joint capsule -  lax
• Glenoid labrum - a fibrocartilaginous ridge surrounding the glenoid cavity. It deepens the cavity and creates a seal with the head of humerus, reducing the risk of dislocation.
• Ligaments - act to reinforce the joint capsule and form the coracoacromial arch.
• Biceps tendon - it acts as a minor humeral head depressor, thereby contributing to stability.

The shoulder joint is supplied by the anterior and posterior circumflex humeral arteries - which are both branches of the axillary artery.

[start-clinical]

[end-clinical]

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