5. Supinator

Origin:

• Superficial head: Lateral epicondyle of the humerus annular ligament, radial collateral ligament
• Deep head: Supinator crest of the ulna, annular ligament, radial collateral ligament

Insertion: Lateral proximal shaft of the radius

Action: Supinates the forearm

Innervation: Deep branch of the radial nerve (C5/6)

Needling

Position: Various (sitting/supine) with arm in midpronation

Palpation: Palpate the upper 1/3 of the posterior aspect of the radius and resist supination to help isolate this muscle

Technique:

• • Direct – Palpate the head of the radius and the ulna next to it on the posterior aspect
    • Needle directly towards the radius using it as your bony backdrop.
    • Needle between the two bones aiming toward the supinator crest of the ulna, using the ulna as a bony backdrop
  • Threading – Needle as above, but redirect the needle in an inferior-to-superior direction along the ulna near its attachment

Caution: Low – the posterior interosseous nerve (a branch of the radial nerve) will pass through this muscle