MedCourseFinder

Structure

Shoulder (glenohumeral) joint

Source-checked · Content last updated · 1 min read ·

This is the date the draft was written, not a medical review date.

The glenohumeral joint is a synovial ball-and-socket joint between the humeral head and the shallow glenoid cavity of the scapula. It is the most mobile joint of the body and, consequently, the most frequently dislocated.

Terminologia Anatomica (Latin): Articulatio humeri · Open in the 3D atlas

Location

It lies at the junction of the arm and the thorax, below the acromion and coracoid process, deep to the deltoid; the axillary nerve passes just below the joint capsule.

Structure

The glenoid is deepened by the fibrocartilaginous labrum. The capsule is lax, reinforced by the glenohumeral ligaments and by the rotator cuff tendons; the coracoacromial arch lies above. The long head of biceps passes through the joint within the intertubercular sulcus. The inferior capsule is the weakest part.

Blood supply

Anterior and posterior circumflex humeral arteries, suprascapular and circumflex scapular arteries, and branches of the thoracoacromial trunk form an anastomosis around the joint.

Innervation

Suprascapular, axillary and lateral pectoral nerves (mainly C5-C6 roots) supply the capsule. Pain from the shoulder is felt over the lateral deltoid region and may be referred from the diaphragm (C3-C5 via the phrenic nerve).

Function

It allows flexion, extension, abduction, adduction, medial and lateral rotation and circumduction, working with scapulothoracic movement (scapulohumeral rhythm: glenohumeral and scapular motion combine during abduction).

Clinical correlations

Anterior-inferior dislocation is by far the commonest; the axillary nerve (regimental badge area numbness, deltoid weakness) and the humeral head or glenoid rim (Hill-Sachs and Bankart lesions) may be injured. Other conditions include adhesive capsulitis, impingement and acromioclavicular sprain.

Common exam points

  • Ball-and-socket synovial joint; stability is sacrificed for mobility (shallow glenoid, lax capsule).
  • Stabilisers: labrum, glenohumeral ligaments, rotator cuff, long head of biceps.
  • Anterior dislocation: axillary nerve injury, test sensation over the lateral shoulder and deltoid contraction.
  • Weakest point of the capsule is inferior.
  • Axillary nerve (C5-C6) passes through the quadrangular space with the posterior circumflex humeral artery.

References

  1. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. Elsevier — Tier 3 (textbook)
  2. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. Wolters Kluwer, 8th edition (2018) — Tier 3 (textbook)
  3. Netter FH. Atlas of Human Anatomy. Elsevier — Tier 3 (textbook)

References are listed only where the article cites them. See the sources page for the full policy. How sources are chosen and credited

Back to the index