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Glenohumeral joint

The glenohumeral joint is a synovial ball-and-socket joint formed between the head of the humerus and the glenoid cavity of the scapula. It is the most mobile joint in the human body, allowing a wide range of upper-limb movements while relying heavily on soft-tissue stabilizers for joint integrity.

This joint is a central focus in musculoskeletal anatomy and imaging due to its complex biomechanics, frequent involvement in trauma and overuse conditions, and dependence on surrounding tendons, ligaments, and labrum for stability.

Synonyms

  • Shoulder joint

  • Scapulohumeral joint

Location

  • Located at the lateral aspect of the shoulder

  • Between the humeral head and the glenoid fossa of the scapula

  • Inferior to the acromion

  • Anterior to the scapular spine

  • Lateral to the thoracic cage

  • Enclosed by a fibrous joint capsule

Articular components

  • Humeral head:

    • Spherical articular surface covered by hyaline cartilage

  • Glenoid cavity:

    • Shallow pear-shaped articular surface of the scapula

  • Glenoid labrum:

    • Fibrocartilaginous rim that deepens the glenoid cavity

  • Joint capsule:

    • Thin and lax, allowing wide range of motion

  • Synovial membrane:

    • Lines the inner surface of the capsule

Relations

Superiorly:

  • Acromion

  • Coracoacromial arch

  • Subacromial–subdeltoid bursa

Inferiorly:

  • Axillary recess of the joint capsule

Anteriorly:

  • Subscapularis tendon

  • Coracoid process

Posteriorly:

  • Infraspinatus and teres minor tendons

Laterally:

  • Deltoid muscle

Medially:

  • Scapular neck

Stabilizing structures

  • Rotator cuff tendons:

    • Supraspinatus

    • Infraspinatus

    • Teres minor

    • Subscapularis

  • Glenoid labrum

  • Capsuloligamentous complex:

    • Superior, middle, and inferior glenohumeral ligaments

  • Long head of the biceps tendon (intra-articular, extra-synovial)

X-ray appearance

Plain radiographs (AP, scapular Y, axillary views):

  • Humeral head: Smooth, rounded contour

  • Glenoid: Shallow concave articular surface

  • Joint space: Uniform radiolucent gap

  • Alignment: Humeral head centered on glenoid

  • Surrounding bones: Acromion, clavicle, and coracoid well visualized

CT appearance

Non-contrast CT:

  • Osseous anatomy: Excellent depiction of humeral head and glenoid morphology

  • Articular surfaces: Smooth cortical margins

  • Joint space: Clearly defined

  • Subtle fractures or bone defects: Well visualized

CT lung window:

  • Cortical bone: Sharply defined outer margins

  • Trabecular detail: Enhanced visualization of internal bone architecture

  • Small cortical breaks: More conspicuous than on soft-tissue windows

  • Useful for: Detecting subtle fractures, cortical irregularities, and bone loss

MRI appearance

T1-weighted images:

  • Bone marrow: High signal in humeral head and scapula

  • Articular cartilage: Intermediate signal lining joint surfaces

  • Labrum: Low signal triangular structure along glenoid rim

  • Capsule and ligaments: Low signal intensity

T2-weighted images:

  • Joint fluid: High signal outlining articular surfaces and recesses

  • Articular cartilage: Intermediate-to-high signal

  • Labrum: Low signal relative to fluid

  • Rotator cuff tendons: Low signal

STIR:

  • Fluid-sensitive sequence: Highlights joint fluid and bursae

  • Bone marrow: Suppressed fat signal with high sensitivity to fluid

  • Soft tissues: Clear delineation of capsule, tendons, and surrounding structures

MRI images

Glenohumeral joint MRI IMAGE

CT VRT 3D image

Glenohumeral joint 3D

CT image

Glenohumeral joint CT IMAGE

X Ray image

Glenohumeral joint ap