Arm recoil
Neurological examination for determining muscle tone in newborns
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Arm recoil is a component of the neurological examination of neonates used to assess passive flexor tone of biceps(muscle tone). It is also one of the neuromuscular criteria used in the Ballard Assessment of gestational age.[1][2]
| Arm recoil | |
|---|---|
| Purpose | Determining muscle tone in newborns |
Procedure
Observation
How quickly the forearm returns to flexed original position and the amount of flexion will designate a score.[1]
- Grade 0: Arms remain extended 180 degrees or abnormal movements begin
- Grade 1: Minimal flexion, 140-180 degrees
- Grade 2: Slight flexion, 110-140 degrees
- Grade 3: Moderate flexion, 90-110 degrees
- Grade 4: Quick return to full flexion, less than 90 degrees
Slow of incomplete arm recoil may indicate reduced muscle tone. Asymmetry in the response may also be observed with brachial plexus injury.[6][7]
Interpretation
The greater the tone development (flexor tone), the brisker the recoil will be.[1] This correlates to more advanced gestational age on the Ballard Scale.[8]
Note that for grade 4 score selection occurs when recoil brings the infant's fist into contact with the face; this is seen in term and post term infants.[4]
Leg recoil can be assessed following the same principle.[9]
