Glenohumeral ligaments
Encyclopedia
In human anatomy, the glenohumeral ligaments (GHL) are three ligament
s on the anterior side of the glenohumeral joint
(i.e. between the glenoid cavity
of the scapula
and the head of the humerus
; colloquially called the shoulder
joint). Reinforcing the anterior glenohumeral joint capsule, the superior, middle, and inferior glenohumeral ligaments play different roles in the stability of the head of the humerus depending on arm position and degree of rotation.
In addition to these, the capsule is strengthened in front by two bands derived from the tendons of the Pectoralis major and Teres major respectively.
of the arm
the middle and inferior ligaments become taut while the superior ligament relaxes. The radius of curvature of the head of the humerus is greater superiorly than inferiorly, which further stretches these ligaments so that they keep the articular surfaces of the joint in their close-packed position.
During abduction the greater tubercle
of the humerus comes in contact with the upper margin of the glenoid cavity, which limits maximum abduction. By rotating the humerus laterally, this contact is delayed because the greater tubercle is pulled back so that the bicipital groove faces the acromiocoracoid ligament
. This slightly slackens the inferior fibres of the glenohumeral ligament, allowing an abduction of 90°. Combining abduction with 30° flexion in the plane of the scapula causes a delay in the tightening of the ligament resulting in a maximum abduction of 110°.
During rotation of the arm lateral rotation stretches all three ligaments while medial rotation relaxes them.
|+ Tension of ligaments
|-
! Ligament
! Shoulder motions to pull the ligament taut
! Humeral head motion to pull the ligament taut
|-
| Superior glenohumeral lig.
| Full adduction
| Inferior or anterior glide
|-
| Middle glenohumeral lig.
| External rotation
| Anterior glide
|-
| Inferior glenohumeral lig.
Anterior band
Posterior band
|
Abduction and external rotation
Abduction and internal rotation
| Non specific
|-
| Coracohumeral lig.
| Extremes of flexion, extension, or external rotation
| Inferior glide>
SGHL Ligamentum glenohumerale superior:
This ligament originates in the upper area of the glenoid just before the approach of the long tendon of the M. biceps and also before the labrum. It bridges the joints from posterior medial to anterior medial and attaches just above the tuberculum minus at the area of the sulcus bicipitalis. It is fixed to the capsule and the coraco-humeral ligament and prevents a dislocation towards cranial, but on the other hand contributes little to the anterior stability. This ligament is an important component of the rotator cuff interspace. A loosening can cause recurrent instability of the shoulder joint.
MGHL Ligamentum glenohumerale mediale:
This ligament originates in the front area of the glenoid rim and is attached at the area of the middle facet of the tuberculum minus. It has the greatest variability compared to the other GHL concerning its position and thickness. It is in close proximity to the tendon of the M. subscapularis and is surrounded by the subscapularis bursa. The ligament ensures the joint stability during external rotation while abducing. This function is essential, especially for abduction of more than 60%. The foramen Weitbrecht is located between the superior and medial GHL (gleno-humeral ligament) and the foramen Rouviere in-between the medial and inferior GHL.
IGHL Ligamentum glenohumerale inferior:
It is build up of an anterior (AIGHL) and a posterior (PIGHL) belt and an axillary pouch in-between. It is the largest ligament and constitutes two thirds of the entire glenoidal circumference. The origin is at the lower part of the glenoidal rim and it attaches at the area of the surgical humeral neck. It is non-tensed in the adduction, which applies for the axillary pouch too, and spans increasingly during the abduction. This moves the anterior and posterior belt up towards the humeral head. They prevent anterior and posterior dislocation during an abduction of 90 degrees. Of capital importance for the anterior stability is mainly the inferior GHL. It also limits the external rotation with increasing abduction. In the MRI the IGHL is best appreciated when the patient is positioned in the ABER position, that is external rotation while abducing whereupon the hand is placed behind the head. The images are then orientated along the humeral axis.
In order to examine the gleno-humeral ligaments, or the shoulder joint in general, the arthroscopy of course is the modality that reveals the morphology of the structures most precisely and with all the details. But it has to be considered that it is non-economical and rather invasive with all its surgical risks. Takubo et al. proclaims that conventional MRI in the ABER (Abduction / external rotation) position is fairly useful for predicting the state of the AIGHL concerning arthroscopic Bankart repair in advance. They found a sensitivity and specificity for the presence or lack of a sufficiently stable AIGHL of 94% and 82%. Additionally the non-invasive MRI in ABER may be useful for post-operative follow-up of the repaired ligaments. The state of the IGHL is one of the most important factors for achieving a successful arthroscopic Bankart repair and thus essential to evaluate before taking any surgery into account. At the ABER position the AIGHL is thanks to its anatomical nature tensed and parallel to the imaging sections, thus well detectable on MR images.
Not yet in all textbooks represented is the macroscopically recognizable ligamentum glenohumerale spirale. It should not be omitted in the examination and MR interpretation and is part of a detailed analysis of the gleno-humeral joint and its eventual instability. It is important to consider that the additional partial volume effect within the anterior joint capsule interferes with the visualization of the other ligaments. Already in the beginning of the 20th century Delorme described the superficial layer of the anterior shoulder joint capsule as fasciculus obliquus. The macroscopic appearance during external rotation and abduction led to its actual name of tendon GHL spirale. Anatomic dissection showed that the ligament arises from the region of the infraglenoid tubercule and the long head of the triceps muscle as a separate band. It courses cranially in the superficial layer of the anterior shoulder joint capsule, crosses and fuses with the underlying IGHL. Just after establishing a tight connection with the MGHL, it fuses with the posterocranial surface of the subscapularis tendon. And finally the ligament and the tendon insert together on the lesser tubercle of the humerus. Even without the medial GHL, whose absence is a common variability, the spiral GHL does keep its anatomic position and main course of the fibers. Then, the low MR signal intensity stripe of the spiral GHL is detectable on the posterior, articular side of the subscapular muscle.
The fibers of the spiral and medial GHL are close to the coronal oblique plane. Consequently in the oblique sagittal plane, a nearly vertical position of the spiral and medial GHL can be visualized as one or two intense vertical stripes. Additionally may the clear visualization of them on axial MR images be explained with the cross-sectional view of the separate anatomic structure.
A shoulder dislocation is a common injury and concerns mostly the musculoskeletal system. In 70% of the cases the injury is based on sporting activity, first and foremost on contact sports. The type of injuries often vary depending on the age of the patients. In young patients are labral lesions including rupture of the anteroinferior capsule typically found. So-called Bankart lesions. There is a smooth transition of labral and capsular lesions, with different effects on the dislocation rate. After the age of 40, ruptures of the capsule intermedially or at the humeral insertion are typical. So-called HAGL (humeral avulsion of gleno-humeral ligament) lesions. Proof of overexpansion or enlargement of the anterior joint capsule still to date is a radiological challenge. In this elderly patient pool must one also always be aware of rotator cuff tears and eventual harm of the tuberculum majus.
HAGL lesions
The modality of choice for detection of HAGL lesions is the arthographic MR. At the acute stage, an enclosed hemarthrosis can be verifying. Later on, a native MRI cannot be significant. Inferior lying HAGL lesions require a very experienced radiologist, who is familiar with the assessment of shoulder pathologies.
HAGL lesions can be identified thanks to the “J-symbol” on MR images. Caused is the sign by rupture of the inferior GHL and contrast agent leakage into the caudal recess. If the capsular rupture is located dorsally, the lesion is called RHAGL (reversed avulsion of gleno-humeral ligament).
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
s on the anterior side of the glenohumeral joint
Glenohumeral joint
The glenohumeral joint, or shoulder joint, is a multiaxial synovial ball and socket joint and involves articulation between the glenoid fossa of the scapula and the head of the humerus...
(i.e. between the glenoid cavity
Glenoid cavity
The glenoid cavity is a shallow pyriform, articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.This cavity forms the...
of the scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
and the head of the humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
; colloquially called the shoulder
Shoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...
joint). Reinforcing the anterior glenohumeral joint capsule, the superior, middle, and inferior glenohumeral ligaments play different roles in the stability of the head of the humerus depending on arm position and degree of rotation.
Location
The ligaments may be best seen by opening the capsule at the back of the joint and removing the head of the humerus:- One on the medial side of the joint passes from the medial edge of the glenoid cavityGlenoid cavityThe glenoid cavity is a shallow pyriform, articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.This cavity forms the...
to the lower part of the lesser tubercle of the humerus. - A second at the lower part of the joint extends from the under edge of the glenoid cavity to the under part of the anatomical neck of the humerus.
- A third at the upper part of the joint is fixed above to the apex of the glenoid cavity close to the root of the coracoid process, and passing downward along the medial edge of the tendon of the Biceps brachii, is attached below to a small depression above the lesser tubercle of the humerus.
In addition to these, the capsule is strengthened in front by two bands derived from the tendons of the Pectoralis major and Teres major respectively.
Function
During abductionAbduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...
of the arm
Arm
In human anatomy, the arm is the part of the upper limb between the shoulder and the elbow joints. In other animals, the term arm can also be used for analogous structures, such as one of the paired forelimbs of a four-legged animal or the arms of cephalopods...
the middle and inferior ligaments become taut while the superior ligament relaxes. The radius of curvature of the head of the humerus is greater superiorly than inferiorly, which further stretches these ligaments so that they keep the articular surfaces of the joint in their close-packed position.
During abduction the greater tubercle
Greater tubercle
The greater tubercle of the humerus is situated lateral to the head of the humerus and posteriolateral to the lesser tubercle.Its upper surface is rounded and marked by three flat impressions....
of the humerus comes in contact with the upper margin of the glenoid cavity, which limits maximum abduction. By rotating the humerus laterally, this contact is delayed because the greater tubercle is pulled back so that the bicipital groove faces the acromiocoracoid ligament
Coracoacromial ligament
The Coracoacromial Ligament is a strong triangular band, extending between the coracoid process and the acromion.It is attached, by its apex, to the summit of the acromion just in front of the articular surface for the clavicle; and by its broad base to the whole length of the lateral border of the...
. This slightly slackens the inferior fibres of the glenohumeral ligament, allowing an abduction of 90°. Combining abduction with 30° flexion in the plane of the scapula causes a delay in the tightening of the ligament resulting in a maximum abduction of 110°.
During rotation of the arm lateral rotation stretches all three ligaments while medial rotation relaxes them.
|-
! Ligament
! Shoulder motions to pull the ligament taut
! Humeral head motion to pull the ligament taut
|-
| Superior glenohumeral lig.
| Full adduction
| Inferior or anterior glide
|-
| Middle glenohumeral lig.
| External rotation
| Anterior glide
|-
| Inferior glenohumeral lig.
Anterior band
Posterior band
|
Abduction and external rotation
Abduction and internal rotation
| Non specific
|-
| Coracohumeral lig.
| Extremes of flexion, extension, or external rotation
| Inferior glide>
Imaging
SGHL Ligamentum glenohumerale superior:
This ligament originates in the upper area of the glenoid just before the approach of the long tendon of the M. biceps and also before the labrum. It bridges the joints from posterior medial to anterior medial and attaches just above the tuberculum minus at the area of the sulcus bicipitalis. It is fixed to the capsule and the coraco-humeral ligament and prevents a dislocation towards cranial, but on the other hand contributes little to the anterior stability. This ligament is an important component of the rotator cuff interspace. A loosening can cause recurrent instability of the shoulder joint.
MGHL Ligamentum glenohumerale mediale:
This ligament originates in the front area of the glenoid rim and is attached at the area of the middle facet of the tuberculum minus. It has the greatest variability compared to the other GHL concerning its position and thickness. It is in close proximity to the tendon of the M. subscapularis and is surrounded by the subscapularis bursa. The ligament ensures the joint stability during external rotation while abducing. This function is essential, especially for abduction of more than 60%. The foramen Weitbrecht is located between the superior and medial GHL (gleno-humeral ligament) and the foramen Rouviere in-between the medial and inferior GHL.
IGHL Ligamentum glenohumerale inferior:
It is build up of an anterior (AIGHL) and a posterior (PIGHL) belt and an axillary pouch in-between. It is the largest ligament and constitutes two thirds of the entire glenoidal circumference. The origin is at the lower part of the glenoidal rim and it attaches at the area of the surgical humeral neck. It is non-tensed in the adduction, which applies for the axillary pouch too, and spans increasingly during the abduction. This moves the anterior and posterior belt up towards the humeral head. They prevent anterior and posterior dislocation during an abduction of 90 degrees. Of capital importance for the anterior stability is mainly the inferior GHL. It also limits the external rotation with increasing abduction. In the MRI the IGHL is best appreciated when the patient is positioned in the ABER position, that is external rotation while abducing whereupon the hand is placed behind the head. The images are then orientated along the humeral axis.
In order to examine the gleno-humeral ligaments, or the shoulder joint in general, the arthroscopy of course is the modality that reveals the morphology of the structures most precisely and with all the details. But it has to be considered that it is non-economical and rather invasive with all its surgical risks. Takubo et al. proclaims that conventional MRI in the ABER (Abduction / external rotation) position is fairly useful for predicting the state of the AIGHL concerning arthroscopic Bankart repair in advance. They found a sensitivity and specificity for the presence or lack of a sufficiently stable AIGHL of 94% and 82%. Additionally the non-invasive MRI in ABER may be useful for post-operative follow-up of the repaired ligaments. The state of the IGHL is one of the most important factors for achieving a successful arthroscopic Bankart repair and thus essential to evaluate before taking any surgery into account. At the ABER position the AIGHL is thanks to its anatomical nature tensed and parallel to the imaging sections, thus well detectable on MR images.
Not yet in all textbooks represented is the macroscopically recognizable ligamentum glenohumerale spirale. It should not be omitted in the examination and MR interpretation and is part of a detailed analysis of the gleno-humeral joint and its eventual instability. It is important to consider that the additional partial volume effect within the anterior joint capsule interferes with the visualization of the other ligaments. Already in the beginning of the 20th century Delorme described the superficial layer of the anterior shoulder joint capsule as fasciculus obliquus. The macroscopic appearance during external rotation and abduction led to its actual name of tendon GHL spirale. Anatomic dissection showed that the ligament arises from the region of the infraglenoid tubercule and the long head of the triceps muscle as a separate band. It courses cranially in the superficial layer of the anterior shoulder joint capsule, crosses and fuses with the underlying IGHL. Just after establishing a tight connection with the MGHL, it fuses with the posterocranial surface of the subscapularis tendon. And finally the ligament and the tendon insert together on the lesser tubercle of the humerus. Even without the medial GHL, whose absence is a common variability, the spiral GHL does keep its anatomic position and main course of the fibers. Then, the low MR signal intensity stripe of the spiral GHL is detectable on the posterior, articular side of the subscapular muscle.
The fibers of the spiral and medial GHL are close to the coronal oblique plane. Consequently in the oblique sagittal plane, a nearly vertical position of the spiral and medial GHL can be visualized as one or two intense vertical stripes. Additionally may the clear visualization of them on axial MR images be explained with the cross-sectional view of the separate anatomic structure.
A shoulder dislocation is a common injury and concerns mostly the musculoskeletal system. In 70% of the cases the injury is based on sporting activity, first and foremost on contact sports. The type of injuries often vary depending on the age of the patients. In young patients are labral lesions including rupture of the anteroinferior capsule typically found. So-called Bankart lesions. There is a smooth transition of labral and capsular lesions, with different effects on the dislocation rate. After the age of 40, ruptures of the capsule intermedially or at the humeral insertion are typical. So-called HAGL (humeral avulsion of gleno-humeral ligament) lesions. Proof of overexpansion or enlargement of the anterior joint capsule still to date is a radiological challenge. In this elderly patient pool must one also always be aware of rotator cuff tears and eventual harm of the tuberculum majus.
HAGL lesions
The modality of choice for detection of HAGL lesions is the arthographic MR. At the acute stage, an enclosed hemarthrosis can be verifying. Later on, a native MRI cannot be significant. Inferior lying HAGL lesions require a very experienced radiologist, who is familiar with the assessment of shoulder pathologies.
HAGL lesions can be identified thanks to the “J-symbol” on MR images. Caused is the sign by rupture of the inferior GHL and contrast agent leakage into the caudal recess. If the capsular rupture is located dorsally, the lesion is called RHAGL (reversed avulsion of gleno-humeral ligament).