Abdulrahman Alraddadi

Histology, vascularity and innervation of the glenoid labrum:

Background: Although the glenoid labrum has an important role in shoulder stability, little is known about its composition, vascularity and innervation. The aims of this study were therefore to evaluate the histology, vascularity and innervation of the glenoid labrum. Materials and methods: Ten glenoid labrum specimens (three male, two female: mean age 81.2 years, range 76–90 years) were detached at the glenoid neck. Following decalcification, sections were cut through the whole thickness of each specimen perpendicular to the glenoid labrum at 12 radii corresponding to a clock face superimposed on the glenoid fossa. Then they were stained using haematoxylin and eosin, a silver nitrate protocol or subjected to immunohistochemistry using anti-protein gene protein 9.5 to demonstrate neuronal processes. Results: The labrum was fibrocartilaginous, being more fibrous in its free margin. There was a variable distribution of blood vessels, being more vascular in its periphery, with many originating from the fibrous capsule and piercing the glenoid labrum. Immunohistochemistry revealed positive staining of nerve fibres within the glenoid labrum. Conclusion: The glenoid labrum is fibrocartilaginous, being more fibrous in its periphery, and is vascularized, with the anterosuperior aspect having a rich blood supply. Free sensory nerve fibres were also present; no encapsulated mechanoreceptors were observed. The presence of sensory nerve fibres in the glenoid labrum could explain why tears induce pain. It is postulated that these sensory fibres could play a role in glenohumeral joint proprioception.

Blood supply and vascularity of the glenoid labrum: Its clinical implications:

Background: Tears of the glenoid labrum are common after dislocation of the glenohumeral joint. The outcome for healing or surgical reconstruction of the glenoid labrum relies on the extent of its vascularization. This study aims to evaluate the glenoid labrum blood supply and to determine its regional vascularity. Materials and Methods: A total of 140 shoulders (30 male and 40 female cadavers) were examined: mean age 81.5 years, range 53–101 years. All blood vessels around the glenohumeral joint were dissected and recorded. Ten specimens with the glenoid labrum and fibrous capsule attached were randomly selected and detached at the glenoid neck and subjected to decalcification. Sections (10–20 μm) were cut through the whole thickness of each specimen from the centre of the glenoid fossa perpendicular to the glenoid labrum at 12 radii corresponding to a clock face superimposed on the glenoid. Sections were stained using haematoxylin and eosin and then examined. Results: The blood supply to the glenoid labrum is by direct branches from the second part of the axillary artery, subscapular, circumflex scapular and anterior circumflex humeral and posterior circumflex humeral arteries, as well as branches of muscular arteries supplying the surrounding muscles. Conclusion: This study shows that the glenoid labrum has a rich blood supply suggesting that, regardless of the types of the glenoid labrum lesions or their management, an excellent outcome for glenoid labrum healing and joint stability is possible. The observations also suggest that the blood supply to the glenoid labrum is sufficient, enabling its reattachment.

Bare spot and tubercle of Assaki

Background The definition of the bare spot and tubercle of Assaki is controversial, with studies reporting different incidences, locations, and clinical significance. The aims of this study were to evaluate the incidence of the bare spot, to determine the length and width of the bare spot, and to assess the relationship between the bare spot and tubercle of Assaki. Materials and methods A total of 140 shoulders from 30 men and 40 women were dissected and examined. After exposure of the glenoid fossa with the glenoid labrum attached, direct measurement of the length and width of the bare spot was undertaken using digital calipers. The repeatability and reliability of the measurements was assessed using Kruskal-Wallis one way analysis of variance on ranks, with statistical significance set at P < .05. Results A bare spot was observed in 80.7% (n = 113) of shoulders, being more common in men than in women, with an overall mean length and width of 7.2 mm and 6.2 mm. It was significantly longer (P = .002) and wider (P = .018) in men. Conclusion A bare spot exists within the glenoid fossa and differs from the tubercle of Assaki. It is a characteristic round to oval lesion in the central or eccentric cartilage. It should not be misdiagnosed as a pathologic lesion.