|Author: A. Chandrasekhar, MD||Consultant: M. Kelly, MD and M. Merchut, MD|
Patient should be relaxed and positioned symmetrically, preferably lying supine.
Biceps reflex: (C5-C6) With the arm gently flexed at the elbow, tap the biceps tendon with a reflex hammer. It may help to locate this tendon with your thumb, and strike your own thumb with the hammer. There should be a reflex contraction of the biceps brachii muscle (elbow flexion).
Triceps reflex: (C7-C8) With the elbow in flexion, tap the triceps tendon, just proximal to the elbow, with a reflex hammer. The arm could also be abducted at the shoulder for this maneuver. There should be a reflex contraction of the triceps muscle (elbow extension).
Brachiradialis reflex: (C5-C6)
Knee reflex: (L2-L4) Slightly lift up the leg under the knee, and tap the patellar tendon with a reflex hammer. There should be a reflex contraction of the quadriceps muscle (knee extension). (If performed in a sitting position, have the legs dangle over the edge of the chair or table).
Ankle reflex: (S1) Slightly externally rotate at the hip, and gently dorsiflex the foot, tapping the Achilles tendon with a reflex hammer. There should be a reflex contraction of the gastrocnemius muscle (plantar flexion).
When the reflexes are absent try eliciting it after re-enforcing (Jendrassik maneuver0, by asking the patient to interlock and pull flexed fingers.
Deep tendon reflexes should be graded on a scale of 0-4 as follows:
0 = absent despite reinforcement
1 = present only with reinforcement
2 = normal
3 = increased but normal
4 = markedly hyperactive, with clonus