Coraco-clavicular joint: normal variant in humans. A radiographic demonstration in the human and non-human primate

A review of the coracoclavicular joint: Description, etiology, and clinical significance

The coracoclavicular joint (CCJ) is a synovial joint that forms between the conoid tubercle of the clavicle and the coracoid process of the scapula in approximately 2.5% of the population. The number of bilateral to unilateral cases is almost equal. The number of right-sided and left-sided cases is also almost equal. It is found in both males and females but most often in male adults. Very few cases have been identified in juveniles. Found in populations all over the world, the highest frequencies of CCJ are in Asia. The etiology is unknown but it is most likely caused by metaplastic change of the trapezoid and surrounding tissue due to compression and friction of the coracoacromial ligament between the clavicle and coracoid process. Typically asymptomatic, but if so, the most common complaint is anterior should pain exacerbated by extreme abduction. Successful treatment includes steroid injection and surgical excision.

Imaging of the Acromioclavicular Joint: Anatomy, Function, Pathologic Features, and Treatment

The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.

Morphometric Study of Clavicular Facet of Coracoclavicular Joint in Adult Indian Population

INTRODUCTION

Anthropologists have used Coracoclavicular Joint (CCJ), a non-metric anatomical variant in population, as a marker for population migration from prehistoric times to present.

AIM

The aim of this osteological study was to determine the incidence and morphometry of articular facet of CCJ on conoid tubercle of clavicle in Indian population, as Indian studies are scanty and incomplete.

MATERIALS AND METHODS

The study was done on 144 adult human clavicles (76 right and 68 left; 93 males and 51 females) collected from osteology museum in Department of Anatomy, Maulana Azad Medical College, New Delhi, India. The presence of articular facet on the conoid tubercle was determined and Maximum Antero-Posterior (MAPD) and maximum transverse diameter (MTD) was measured by digital vernier calliper. The incidence was compared on the basis of sex, side and with other osteological studies in the world. Statistical analysis was done using the Chi-Square test for nominal categorical data and student's t-test for normally distributed continuous variables in Microsoft Excel 2007 to assess the relationship between the examined variables.

RESULTS

Articular facet on conoid tubercle was found in 8 cases (5.6%). Seven (9.2%) were present on the right side and one (1.5%) on the left side. Seven cases (7.5%) were present in males and one case (2%) was found in females. The facets were generally oval, with MAPD and MTD of 12.28 and 17.17 mm respectively. A significant side variation was present with right sided facet being more common. The left sided facet was more transversely elongated than right. In males, the facets were more elongated antero-posteriorly than in females.

CONCLUSION

The Indian population showed an incidence of 5.6%, which was comparable to other ethnic groups in world population. The morphometric and side differences could be attributed to the occupational factors and range of movements associated with the CCJ. The CCJ should be borne in mind as a differential diagnosis for thoracic outlet syndrome and in general for shoulder pain.

The coracoclavicular joint. A systematic review and meta-analysis

The coracoclavicular joint (CCJ) is considered as a rare articulation in humans. Though rarely it could be symptomatic, its presence should be acknowledged by physicians. The aim of this systematic review is to conduct an evidence synthesis on the prevalence of this condition in different ethnic populations. Thirty nine studies including 51 sub-studies met the inclusion criteria. The meta-analytical results showed true prevalence values of ≃5%, ≃7% and ≃2.7% from skeletal, cadaveric and radiological studies, respectively. The bilateral occurrence of CCJ was found to be approximately the half of the crude prevalence and that in all study types. European populations showed the least frequency whereas the Eastern Asian and Native American populations showed the highest values in skeletal/cadaveric studies. European, modern American, Native American and modern South American populations showed the least CCJ occurrence rates in radiological studies. The Chinese population stood out from all other ancestries with a prevalence of 21%, followed by the Southeast Asians with a frequency of 6%. No association was found with variables such as sex or side. This evidence-based anatomical and anthropological review shed the light on the rare and poorly investigated CCJ. It yielded more accurate overall and ancestry-based frequencies from skeletal, cadaveric and radiological studies.

Symptomatic coracoclavicular joint: incidence, clinical significance and available management options

PURPOSE

Coracoclavicular joint (CCJ) is a rare anomalous joint occasionally found between the coracoid process of scapula and the conoid tubercle of clavicle. The articulation has been extensively studied by means of anatomical, osteological and radiological investigations. Most cases are discovered incidentally, with the symptomatic variety remaining an exceptional rarity. Our aim was to review all reported symptomatic CCJ to increase the level of evidence and formulate a treatment algorithm to aid clinicians in management planning.

METHODS

A thorough literature search was performed, and data from 17 (n = 17) symptomatic cases of CCJ were analysed.

RESULTS

CCJ is a rare finding and mostly an incidental discovery, which is rarely symptomatic. However, when symptomatic, the most common symptom is shoulder pain. The mean age at presentation is 42 years, with a male:female ratio of 1.4:1. Brachial plexus involvement was the most common pathophysiological explanation provided. First-line treatment was conservative, with a very low success rate of 5.9%. Surgical intervention in the form of excision of anomalous joint by osteotomy had success rate of 100%.

CONCLUSIONS

Symptomatic CCJ is rare, and its rarity leads to lack of awareness in the general orthopaedic community. When symptomatic, CCJ may lead to delayed diagnosis or inappropriate management due to lack of evidence and poor description in most orthopaedic textbooks. Despite its low success rate, conservative treatment is advocated before embarking upon surgical intervention.

A symptomatic coracoclavicular joint

Bilateral coracoclavicular joints were found in a 44-year-old male patient following a fall. He had an Indonesian mother and a Dutch father. Prior to the injury he was asymptomatic and had full range of movement in both shoulders but the trauma resulted in pain and limitation of movement in the left shoulder which required resection of the anomalous joint, after which full pain-free movement was restored.

Coracoclavicular joint: osteologic study of 1020 human clavicles

We examined 1020 dry clavicles from cadavers of Italian origin to determine the prevalence of the coracoclavicular joint (ccj), a diarthrotic synovial joint occasionally present between the conoid tubercle of the clavicle and the superior surface of the horizontal part of the coracoid process. Five hundred and nine clavicles from individuals of different ages were submitted to X-ray examination. Using radiography, we measured the entire length and the index of sinuosity of the anterior lateral curve, on which the distance between the conoid tubercle and the coracoid process depends. We also used radiography to record the differences in prevalence of arthritis in two neighbouring joints, the acromioclavicular and sternoclavicular joints. Of the 1020 clavicles, eight (0.8%) displayed the articular facet of the ccj. No statistical correlation was found between clavicular length and the index of sinuosity of the anterior lateral curve. The prevalence of arthritis in clavicles with ccj was higher than that revealed in clavicles without ccj. The prevalence of ccj in the studied clavicles is lower than that observed in Asian cohorts. Furthermore, ccj is not conditioned by either length or sinuosity of the anterior lateral curve of the clavicle. Finally, the assumption that ccj is a predisposing factor for degenerative changes of neighbouring joints is statistically justified.