Anatomy Bones and Muscles · MU Pleven

15. Shoulder joint

Covers the glenohumeral joint as a ball-and-socket synovial joint, moving through its articular surfaces, the lax capsule and the five ligaments that reinforce it. It then describes the synovial membrane and bursae, the surrounding relations, and the arterial and nerve supply. The note ends with the muscles responsible for each movement, broken down by range for abduction.

Inside: 10 sections · 2 labelled pictures · 12 flashcards · 2 min

Topic 15 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 10 sections, about 279 words (2 min of reading), with 12 flashcards.

In this note

  1. Shoulder Joint (Glenohumeral Joint)
  2. Type of Joint
  3. Articular Surfaces
  4. Capsule
  5. Ligaments
  6. Synovial Membrane
  7. Relations
  8. Blood Supply
  9. Nerve Supply (Hilton’s law – nerves supplying muscles moving the joint also supply the joint)
  10. Movements (muscles acting)

Type of Joint

  • Synovial joint → ball-and-socket type.
  • One of the most mobile joints in the body → but less stable.

Articular Surfaces

  • Head of humerus → large, rounded, forms 1/3 of a sphere.
  • Glenoid cavity of scapula → shallow, pear-shaped depression.
  • Glenoid labrum → fibrocartilaginous rim that deepens the cavity and increases stability.

Capsule

  • Thin, loose fibrous capsule.
  • Attachments:
  • Around glenoid cavity outside the labrum.
  • Around anatomical neck of humerus.
  • Capsule is lax → allows wide range of movement

Ligaments

  1. 1. Capsular ligaments → thickened parts of capsule.
  2. 2. Glenohumeral ligaments (superior, middle, inferior) → strengthen anterior capsule.
  3. 3. Coracohumeral ligament → from coracoid process → greater tubercle; strengthens above.
  4. 4. Transverse humeral ligament → bridges bicipital groove, holds long head of biceps tendon.
  5. 5. Coracoacromial ligament → with coracoid + acromion → forms coracoacromial arch (prevents upward displacement).

Synovial Membrane

  • Lines capsule.
  • Prolonged into tendon sheath of long head of biceps.
  • Bursae:
  • Subacromial (between deltoid & supraspinatus tendon).
  • Subscapular (between subscapularis tendon & capsule).

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