The glenocapsular ligament and the posterosuperior part of the joint capsule of the shoulder are well vascularized

The glenocapsular ligament and the posterosuperior part of the joint capsule of the shoulder are well vascularized, by Põldoja, Rahu, Kask, et al. KSSTA (2018) 26(1): 146-151.

Abstract
Purpose
A detailed structural anatomy of the posterosuperior shoulder capsule and “glenocapsular ligament” is still rather unknown. The purpose of this study was meticulously to investigate and describe the structure and blood supply of the glenocapsular ligament on the posterosuperior shoulder joint capsule.

Method
Sixteen fixed and twelve fresh cadaveric shoulder specimens with a mean age of 73.4 (±6.4) years were analysed. Dissection without arterial injection was performed on the 16 fixed specimens—using an alcohol–formalin–glycerol solution. Before dissection, the 12 fresh specimens received of arterial injection a 10% aqueous dispersion of latex solution. After the injection, these shoulders were also fixed in an alcohol–formalin–glycerol solution.

Results
The glenocapsular ligament was found in all 28 specimens. Single or double parallel-running bundles of connective tissue fibres were found to form a capsular-ligamentous structure on the posterosuperior part of the joint capsule. One part of the ligament was mediosuperior, another posterosuperior. The mediosuperior part varied in shape, and in 12 of 28 cases, it was absent. The glenocapsular ligament arose from the supraglenoid tubercle and posterior part of the collum scapulae and inserted into the semicircular humeral ligament. The posterior ascending branch of the circumflex scapular artery directly fed small branches laterally and medially to the joint capsule, supplying the glenocapsular ligament and the deep layer of the joint capsule.

Conclusion
The glenocapsular ligament is a constant anatomical structure that consists of one or two different parts. The glenocapsular ligament and the posterosuperior part of the joint capsule appear well vascularized via the posterior ascending branch of the circumflex scapular artery.

Clinical relevance
It is the hope of the authors that this anatomical study can help surgeons who perform open or arthroscopic surgery to the posterior part of the shoulder. Knowledge of the vascular anatomy presented in this study may be especially important when incisions are made to the posterior part of the shoulder, and should minimize the risk of complications.

The importance of Blumensaat’s line morphology for accurate femoral ACL footprint evaluation using the quadrant method

The importance of Blumensaat’s line morphology for accurate femoral ACL footprint evaluation using the quadrant method, by Yahagi, Iriuchishima,, Horaguchi, et al. KSSTA (2018) 26(2):455–461.

Morphological variation of the Blumensaat’s line
Following Iriuchishima’s classification*, the morphology of the Blumensaat’s line was classified into straight, small hill, and large hill types.

Straight type
The Blumensaat’s line (intercondylar roof) appeared more or less straight, and the transition from the Blumensaat’s line to the posterior cortex was clearly defined.

Small hill type
A protrusion spanning less than half of the line was observed at the posterior (proximal) part of the Blumensaat’s line.

Large hill type
A protrusion spanning more than half of the line was observed at the proximal part of the the Blumensaat’s line.

*Iriuchishima T, Ryu K, Aizawa S, Fu FH (2016) Blumensaat’s line is not always straight: morphological variations of the lateral wall of the femoral intercondylar notch. Knee Surg Sports Traumatol Arthrosc 24:2752–2757

iriuchishima-blumensaat-line-morphology
Morphological variations of the Blumensaat’s line. In Iriuchishima’s classification, the morphology of the Blumensaat’s line has three types of variations: straight type, small hill type, and large hill type

Grid placement in the quadrant method
In the same images used for the morphological evaluation of the Blumensaat’s line, four types of quadrant grid placement were evaluated according to the morphological variations of the Blumensaat’s line and the chondral lesion

  • Grid (1) Without consideration of hill existence and not including the chondral lesion. The baseline of the quadrant grid was matched to the anterior part of the Blumensaat’s line. The lower and side line of the grid were tangential to the medial wall of the lateral femoral condyle.
  • Grid (2) Without consideration of hill existence and including the chondral lesion. The base line of the grid was determined as in Grid 1. The lower and side line were tangential to the articular surface.
  • Grid (3) With consideration of hill existence and not including the chondral lesion. The baseline of the grid was the line connecting the anterior edge of the Blumensaat’s line and the top of the hill. The lower and side line of the grid were tangential to the medial wall of the lateral femoral condyle.
  • Grid (4) With consideration of hill existence and including the chondral lesion. The baseline of the grid was determined as in Grid 3. The lower and side line were tangential to the articular surface. The measurement accuracy of the Image J software were, 0.1 mm and 0.1 mm2.
yahagi2017-quadrant-grid-placement
Quadrant grid placement according to the morphological variations of the Blumensaat’s line and the chondral lesion. According to the morphological variations of the Blumensaat’s line and the chondral lesion, quadrant grids were placed as: Grid (1) without consideration of hill existence and not including the chondral lesion. Grid (2) without consideration of hill existence and including the chondral lesion. Grid (3) with consideration of hill existence and not including the chondral lesion. Grid (4) with consideration of hill existence and including the chondral lesion