Anatomic analysis of the whole articular capsule of the shoulder joint, with reference to the capsular attachment and thickness

Abstract

BackgroundAlthough conventional Bankart repair has been the accepted procedure for traumatic anterior glenohumeral instability, the humeral avulsion of the glenohumeral ligament or an elongation of the capsule remains challenging to decide the appropriate treatment. The anatomical knowledge regarding the whole capsule of glenohumeral joint is necessary to accurately treat for the capsular disorders. The aims of the current study were to investigate the anatomical features of capsular attachment and thickness in a whole capsule of glenohumeral joint.MethodsWe used 13 shoulders in the current study. In 9 shoulders, we macroscopically measured the attachment widths of the capsulolabrum complex on the scapular glenoid, and the attachment widths of the capsule on the humerus in reference to the scapular origin of the long head of triceps brachii, and the humeral insertion of the rotator cuff tendons. We additionally used 4 cadaveric shoulders, which were embalmed using Thiel’s method, for the analysis of the thickness in a whole capsule by using micro-CT.ResultsThe glenoidal attachment of the articular capsule appeared to have a consistent width except for the superior part of the origin of the long head of triceps brachii. On the humerus, the articular capsule was widely attached to areas without overlying rotator cuffs, with the widest width (17.3 ± 0.9 mm) attached to the axillary pouch. The inferior part of the capsule, which was consistently thicker than the superior part, continued to the superior part along the glenoid and humeral side edge.ConclusionsThe current study showed that the inferior part of the glenohumeral capsule had a wide humeral attachment from the inferior edge of the subscapularis insertion to the inferior edge of the teres minor insertion via the anatomical neck of the humerus, and the thickness of it was thicker than the superior part of the capsule.

Proximal and mid-thigh fascia lata graft constructs used for arthroscopic superior capsule reconstruction show equivalent biomechanical properties: an in vitro human cadaver study

“…In the study by Nimura et al, 20 it was stated that the superior capsule had an average width of attachment to the greater tuberosity of 4.4 to 9.1 mm, which is different from stating that the thickness of the superior capsule ranged from 4.4 to 9.1 mm throughout. Indeed, in the study conducted by Momma et al, 19 in a color representation through 3-dimensional micro-computed tomography images of the variations in capsular thickness distribution, it was shown that the superior parts of the capsule were consistently thinner, ranging from 0.1 to 0.5 mm, whereas at the glenoid and humeral attachment sites the superior, inferior and anterior parts of the capsule were thicker, ranging from 0.5 to 8.0 mm. The results of the present study suggest that the decreased superior translation of the humeral head shown in the biomechanical studies that used the SCR cadaveric models might have been explained by the influence of other external variables.…”

Shoulder scaption is dependent on the behavior of the different partitions of the infraspinatus muscle

“…Yellow arrows indicated the border of each partition. The SWE images were displayed in color-coded map with harder tissue represented in red and softer tissue in blue the anterior margin of the highest impression of the greater tuberosity [22][23][24][25]31]. Kato et al demonstrated that the ISP muscle was comprised of two parts, namely the transverse and oblique parts [15].…”

“…Recent detailed anatomical studies demonstrated that the ISP muscle was anatomically divided into two or three distinct neuromuscular partitions based on differences in their attachment sites, muscle fiber directions, and intramuscular innervations [3,6,15,22,31]. Several authors demonstrated that the anterior-most region of the humeral insertion of the ISP muscle almost reached the anterior margin of the highest impression of the greater tuberosity [22][23][24][25]31]. In addition, Kato et al found that one of the partitions of the ISP muscle was innervated by branches arising from the supraspinatus muscle [15].…”

Anatomic Analysis of the Attachment of the Posteroinferior Labrum and Capsule to the Glenoid: A Cadaveric Study

“…Although the authors examined the length of the labral attachment using 2-hour clock-referent intervals, they did not provide the detailed values for the respective length at each clock position. Momma et al 15 reported that the length of the labral attachment viewed from a cross section of the glenoid neck was 7.4 mm at the posterior edge of the origin of the long head of the triceps brachii, which was slightly inferior to the 7 o'clock position, and the length was greater than at the 9 o'clock position. However, the position of the posterior edge of the origin of the long head of the triceps brachii was unclear.…”