Blood Supply and Nerve Supply of the Shoulder Joint
Blood Supply
The shoulder joint is supplied by four sets of vessels:
| Vessel | Origin |
|---|---|
| Anterior circumflex humeral artery | 3rd part of axillary artery |
| Posterior circumflex humeral artery | 3rd part of axillary artery |
| Suprascapular artery | Thyrocervical trunk (1st part of subclavian) |
| Subscapular artery | 3rd part of axillary artery |
Nerve Supply
The shoulder joint is supplied by three nerves (all from the brachial plexus, root values C5, C6):
| Nerve | Root Value | Notes |
|---|---|---|
| Axillary nerve | C5, C6 | Gives branch to capsule as it passes through quadrangular space; closely related to inferior capsule |
| Musculocutaneous nerve | C5, C6, C7 | Supplies anterosuperior capsule |
| Suprascapular nerve | C5, C6 | Supplies posterosuperior capsule |
Clinical Note
Hilton’s Law: A nerve supplying a joint also supplies the muscles moving that joint and the skin over those muscles. The shoulder joint is supplied by nerves that also supply the deltoid, supraspinatus, infraspinatus, and subscapularis.
Axillary nerve injury is the most clinically important — dislocation of the shoulder joint or fracture of the surgical neck of the humerus may damage the axillary nerve due to its close relation to the inferior joint capsule.
Shoulder tip pain (referred pain): Irritation of the diaphragmatic peritoneum causes referred pain at the shoulder tip because the phrenic nerve (C3, C4) and the supraclavicular nerves (C3, C4) share the same spinal segments.