Glenoid labrum

Glenoidal labrum
Lateral view of the shoulder showing the glenoid labrum (marked "glenoid ligament")
Details
Identifiers
Latin	labrum glenoidale
Dorlands /Elsevier	l_01/12474070
TA	A03.5.08.002
FMA	23290
*Anatomical terminology* [edit on Wikidata]

The glenoid labrum (glenoid ligament) is a fibrocartilaginous rim attached around the margin of the glenoid cavity in the shoulder blade. The shoulder joint is considered a 'ball and socket' joint. However, in bony terms the 'socket' (the glenoid fossa of the scapula) is quite shallow and small, covering at most only a third of the 'ball' (the head of the humerus). The socket is deepened by the glenoidal labrum.

The labrum is triangular in section, the base is fixed to the circumference of the cavity, while the free edge is thin and sharp.

It is continuous above with the tendon of the long head of the Biceps brachii, which gives off two fasciculi to blend with the fibrous tissue of the labrum.

Structure

Glenoid labrum. Schematic drawing of the transverse section. Morphologic variants of the glenoid labrum with relative distribution in percentage for the anterior labrum. a: 50%. Triangular with line of increased signal intensity along the hyalin articular cartilage. b: 20%. Rounded. c: 7%. Comma-shaped flattened. d: 3%. Absent. e: 15%. Cleaved. f: 8%. Notched. g: Central increase in signal intensity. h: Linear increase in signal intensity. The posterior labrum generally exhibits a triangular or rounded form.

Clinical significance

Injury

Tearing of the labrum can occur from either acute trauma or repetitive shoulder motion such as in the sports of swimming and baseball. Acute trauma may be from dislocation of the shoulder, direct blows to the shoulder, and other accidents of the sort. Tears are classified as either superior or inferior in regards to where the tear is in the glenoid cavity. A SLAP lesion (superior labrum, anterior to posterior) is a tear where the glenoid labrum meets the tendon of the long head of the biceps muscle. Symptoms include increased pain with overhead activity, popping or grinding, loss of strength, and trouble localizing a specific point of pain. Because a SLAP lesion involves the biceps, pain and weakness may also be felt when performing elbow flexion with resistance.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

Wikimedia Commons has media related to Glenoid labrum.

upper%20extremity/arthrogramaxial2 at the Dartmouth Medical School's Department of Anatomy
http://orthoinfo.aaos.org/topic.cfm?topic=a00426
http://www.orthospecmd.com/SLAPlesion.html

Joints and ligaments of the arm

Shoulder

Sternoclavicular	Anterior sternoclavicular Posterior sternoclavicular Interclavicular Costoclavicular

Acromioclavicular	Syndesmoses: Coracoacromial Superior transverse scapular Inferior transverse of scapula Synovial: Acromioclavicular Coracoclavicular (trapezoid conoid)

Glenohumeral	Capsule Coracohumeral Glenohumeral (superior, middle, and inferior) Transverse humeral Glenoid labrum

Elbow

Humeroradial	Radial collateral

Humeroulnar	Ulnar collateral

Proximal radioulnar	Anular Oblique cord Quadrate

Forearm

Distal radioulnar	Palmar radioulnar Dorsal radioulnar Interosseous membrane of forearm

Hand

Wrist/radiocarpal	Dorsal radiocarpal/Palmar radiocarpal Dorsal ulnocarpal/Palmar ulnocarpal Ulnar collateral/Radial collateral

Intercarpal midcarpal	Radiate carpal Dorsal intercarpal Palmar intercarpal Interosseous intercarpal Scapholunate Pisiform joint (Pisohamate Pisometacarpal)

Carpometacarpal	Dorsal carpometacarpal Palmar carpometacarpal thumb: Radial collateral Ulnar collateral

Intermetacarpal	Deep transverse metacarpal Superficial transverse metacarpal

Metacarpophalangeal	Collateral Palmar

Interphalangeal	Collateral Palmar

Other	Carpal tunnel Ulnar canal

This article is issued from Wikipedia - version of the Friday, September 11, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.