title: Bony and capsular determinants of glenohumeral 'locking' and 'quadrant' positions.
abstract: The anatomical relationships between the humerus and scapula were examined in the 'locking' and 'quadrant' positions of the glenohumeral joint together with capsular influences on the shape of the 'quadrant'. The glenohumeral joints of four embalmed cadavers were dissected to define capsular attachments and fibre directions. Selected bony and soft tissue landmarks were marked for reference. Four abduction angles were selected to represent 'locking' and parts of the 'quadrant'. A measuring board was designed to allow quantification and standardisation of all test positions. The results show that at 'locking', the postero-superior tip of the glenoid contacted the humeral head in all specimens. During the 'quadrant', a number of soft tissues around the joint were found to be either stretched or compressed. The capsule was found to influence the shape of the 'quadrant', and capsular stretch was noted anteriorly and interiorly. The findings are discussed in relation to clinical implications.
authors.forename: F
authors.initials: F
authors.lastname: Mullen
authors.forename: S
authors.initials: S
authors.lastname: Slade
authors.forename: C
authors.initials: C
authors.lastname: Briggs