Glenoid labrum

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The glenoid labrum , also limbus , acetabular lip or cartilage lip, is a 3–4 mm wide, bulging frame around the joint socket ( cavitas glenoidalis , also glenoid for short ) of the shoulder blade ( shoulder joint ).

The opinion that is still widespread today that the glenoid labrum consists entirely of fibrous cartilage has been refuted since 1962. Fibrous cartilage tissue is only found in a narrow transition zone at the attachment to the bone , otherwise the glenoid labrum consists of predominantly ring-shaped collagen fibers . In the lower rear ( posteroinferior ) part it is very firmly connected to the bone of the joint socket in the upper front ( anterosuperior ) part. On the other hand, the labrum also merges directly into the joint capsule and the surrounding tendons and ligaments at the front ( anterior ) . The glenoid labrum is therefore morphologically not a uniform structure and consists of different zones; it also has anatomical variants.

In addition, the attachment of the long biceps tendon (LBS) is located on the upper ( superior / cranial ) movable part . The transition from the long biceps tendon to the upper glenoid labrum is called the biceps ( tendon ) anchor , labrum-biceps (tendon) complex , labrum-LBS complex or SLAP complex ( SLAP is the abbreviation for superior labrum anterior and posterior ).

function

The glenoid labrum enlarges the bony joint surface of the glenoid by about a third and, thanks to its wedge-shaped structure, creates an additional deepening of the glenoid . As a result, it ensures better coverage of the humerus head and the consistency of the joint partners involved at the edge of the joint increases, resulting in more favorable stress distribution, better centering of the humerus head and stabilization of the shoulder joint. In particular, the SLAP complex is of great importance for the stability of the joint, with the long biceps tendon also playing an important role.

Injuries

Depending on the location, the following types of damage to the glenoid labrum are distinguished:

in the upper area:

in the front area:

in the rear area:

See also

literature

  • T. Barthel, U. König, D. Böhm, J. F. Loehr, F. Gohlke: The anatomy of the Labrum glenoidale . In: The orthopedist . tape 32 , no. 7 , 2003, p. 578-585 , doi : 10.1007 / s00132-003-0487-1 .
  • T. Tischer, R. Putz: The anatomy of the upper labrum complex in the shoulder joint . In: The orthopedist . tape 32 , no. 7 , 2003, p. 572-577 , doi : 10.1007 / s00132-003-0486-2 .

Remarks

  1. ↑ In addition, other similar terms are also used.