Sign In

Triceps Brachii and Anconeus

OVERVIEW
Muscle Test Group:
Triceps brachii and anconeus.

Key Points:

• Muscle group extends the elbow.
• Triceps brachii is composed of three muscle heads: long, medial, lateral.

EXAMINATION
Muscle Function:
Extends the elbow. Long head assists in adduction and extension of the shoulder.
 
Palpation: Long, medial and lateral muscle bellies can be individually palpated on the posterior arm. Palpate just proximal to the olecranon.
 
Strength Testing:
Gravity-lessened Test: Position – patient seated or supine with shoulder and elbow flexed to 90º. Stabilize – forearm and hand to eliminate effect of gravity. Resist – extension of the elbow (in the direction of elbow flexion).
 
Alternate Gravity-lessened Test: Position – patient seated with shoulder abducted to 90º; elbow flexed to 90º. Stabilize – arm on a table close to shoulder height. Patient extends elbow by sliding forearm on the table. Resist – extension of the elbow (in the direction of elbow flexion).
 
Anti-gravity Test:
• Supine Position – shoulder flexed at 90º, elbow in full flexion. Stabilize – the shoulder and arm. Resist – extension of the elbow (in the direction of elbow flexion). Resist up to the unlocked position of slight elbow flexion and not to full extension (locked elbow).  
 
• Prone Position – shoulder abducted at 90º, elbow flexed at 90º, forearm in neutral. Stabilize – with hand under shoulder and arm. Resist – extension of the elbow (in the direction of forearm flexion). Resist up to the unlocked position of slight elbow flexion and not to full extension (locked elbow).   
 
• Seated Position – is not technically accurate, but a common alternate position (for ease of examination); shoulder and elbow flexed at 90º. Stabilize – the shoulder and arm. Resist - extension of the elbow (in the direction of forearm flexion).  Resist up to the unlocked position of slight elbow flexion and not to full extension (locked elbow).   
Possible Substitutions: No true substitutions. Careful not to let effect of gravity give illusion of active elbow extension. 
 
Relevant Anatomy:
Triceps Brachii
Innervation:
• Roots: C6, C7, C8, T1.
• Nerve: Radial nerve.
• Innervation Route: C6, C7, C8, T1 → radial nerve → triceps brachii.
Origin of Long Head: Infraglenoid tubercle of the scapula.
 
Origin of Lateral Head: Lateral and posterior surface of the proximal ½ of the humerus and the lateral intermuscular septum.
 
Origin of Medial Head: Distal ⅔ of the medial and posterior surface of the humus below the radial groove and intermuscular septum.
 
Insertion: Posterior surface of the olecranon process of the ulna and the antebrachial fascia.
 
Anconeus
Innervation: 
• Roots: C7, C8.
• Nerve: Radial nerve, axillary nerve.
• Innervation Route: C7, C8 → axillary nerve → triceps brachii branch → medial triceps brachii branch → anconeus.
Origin: Posterior surface of lateral epicondyle of humerus.
 
Insertion: Lateral side of olecranon process and superior ¼ of posterior surface of ulna.