posterior arm muscles

• Triceps brachi:

  O: Long head (most medial) – infra-glenoid tubercle on glenoid fossa of scapular & glenoid labrum (fibres blending with joint capsule).

  Medial head – inferior & medial aspect of spiral groove on posterior humerus. Posterior aspect of the medial & lateral intermuscular septa.

  Lateral head – superior & lateral aspect of spiral groove on posterior humerus.

  R: Inferiorly (three heads merge to create a broad laminated tendon.
• Triceps brachi:

  I: Insert via tendon (deep and superficial laminae) to posterior aspect of proximal olecranon of ulna & deep fascia of forearm on either side

  A: Extends elbow, Long head adducts GHJ & extends it from flexed position

  NS: Radial nerve (C5, 6, 7, 8, T1)
• Anconeous:

  O: Posterior surface of lateral epicondyle of humerus & adjacent joint capsule

  R: Medially & distally

  I: Lateral surface of olecranon & upper 1/4 of posterior surface of ulna

  A: Assists elbow extension, abducts ulna & extends distal end of ulna during pronation

  NS: Radial nerve (C5, 6, 7, 8, T1)