Muscle Test and Tendon Exam: Flexor Carpi Ulnaris (FCU)

Exams and Signs

Origin:	Humeral head: Humerus (medial epicondyle via common flexor tendon) Ulnar head: Ulna (olecranon, medial margin; shaft, proximal 2/3 posterior via an aponeurosis) Intermuscular septum
Insertion:	Pisiform Hamate 5th metacarpal, base Flexor retinaculum
Innervation:	Cervical root(s): C7–T1 Nerve: ulnar nerve

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

Forearm is supinated. Wrist is in neutral position or slightly extended. Some suggest that the patient should sit with his/her elbow supported on a table for Grades 0–2. For Grade 2, the forearm is in mid-position with the hand resting on the ulnar side.

Examiner’s Actions

One hand supports the patient’s forearm under the wrist. Place the wrist in ulnar deviation and slight wrist extension. Resistance is applied over the fifth metacarpal in the direction of extension and radial deviation. Some suggest that resistance should not be applied for Grades 0–3.

Instructions for the patient

“Bend your wrist. Hold it. Don’t let me pull it down. Keep your fingers relaxed.” For Grade 3, some suggest instructing the patient to “Bend your wrist leading with the little finger.” For Grade 2, they suggest “Bend your wrist keeping your fingers relaxed,” and for Grades 0 and 1, “Try to bend your wrist.”

Presentation Photos and Related Diagrams

FCU Muscle Testing. Patient palmar flexes wrist against resistance while FCU Tendon palpated.
FCU anatomy illustration
This illustration represents the anatomy of the muscle and tendon origin and insertion. Should an individual sustain a laceration as depicted, the observer can assume that the underlying tendon may be at risk for complete transection. A proper examination is needed to determine the integrity of the tendon.

Definition of Positive Result

In muscle testing, a normal result is a positive one. During a normal muscle test, the examiner should observe a normal muscle contraction that can move the joint or tendon against full resistance.

Definition of Negative Result

In muscle testing, an abnormal result is a negative one. During an abnormal muscle test, the examiner should observe an abnormal muscle contraction that can move the joint or tendon. In a complete denervation injury, such as a complete nerve laceration, there will be no evidence of any muscle function and the muscle testing grade will be 0.

Comments and Pearls

To test the two wrist flexors separately, hold the forearm so that the wrist does not lie on the table and ask the patient to perform the flexion motion while the wrist is in ulnar and then radial deviation.

Diagnoses Associated with Exams and Signs

References

Hislop JH, Avers D, Brown M. Daniels and Worthingham's Muscle Testing, Techniques of Manual Examination and Performance Testing. 9th ed. St. Louis, Missouri: Elsevier Saunders, 2014, pp. 138–202.
Kendall FP, McCreary EK, Provance PG. Muscles Testing and Function. 4th ed. Baltimore, MD: Williams & Wilkins, 1993, pp. 235–298.