Origin: | Short Head: Scapula (coracoids apex) Long Head: Scapula (supraglenoid tubercle) Capsule of glenohumeral joint and glenoid labrum |
Insertion: | Radius (radial tuberosity) Bicipital aponeurosis |
Innervation: | Cervical root(s): C5-C6 Nerve: musculocutaneous |
Grading of muscle strength:
Grade | Strength | Description |
5* | Normal | Normal strength |
4* | Good | Movement against external resistance but less than normal |
3 | Fair | Movement against gravity but not against added resistance |
2 | Poor | Movement at the joint with gravity eliminated |
1 | Trace | Trace of contraction but no movement at the joint |
0 | Zero | No contraction or muscle movement |
*The distinction between Grades 4 and 5 is based on comparison with the normal hand and, barring that, extensive experience in testing the hand. |
Position of patient's hand and upper extremity
- Short sitting, arm at side and elbow flexed to 90°; forearm in full pronation to neutral. Alternatively, patient may sit at a table. For Grade 2, some suggest the patient sit with shoulder flexed between 45° and 90°, with the forearm in neutral, and that for Grades 0 and 1, the patient be positioned as for Grades 3–5.
Examiner’s Actions
- While standing at the patient’s side or in front of the patient, support the elbow with one hand and apply resistance with the heel of the other hand over the dorsal (extensor) surface at the wrist. Some suggest that for Grade 2, the examiner cups their hand under the elbow, and that for Grades 1 and 2, the examiner supports the forearm just distal to the elbow and palpates the head of the radius on the dorsal aspect of the forearm.
Instructions for the patient
- “Turn your palm up.” Some suggest “Turn your palm to your face” for Grade 2, and “try to turn your palm so it faces the ceiling” for Grades 0 and 1.