Dooley Noted: 2/25/2016
Last week in a NeuroKinetic Therapy study group, we looked deeply at grip testing with pre- and post-dynamometer measurements.
We looked at the different muscles of the hand that truly power grip strength in concentric contraction, as well as the nerves that drive this power.
We considered the potential impingement along the nerve’s pathway, then used grip testing (in opposition, adduction and flexion) to see if linking the structures created more grip power.
Here is an anatomical breakdown of muscle-nerve drive for grip in concentric contraction:
Grip Muscles driven by median nerve:
– flexor pollicis longus and brevis (digit 1)
– flexor digitorum superficialis (digits 2-5)
– flexor digitorum profundis (digits 2-3)
– opponens pollicis (digit 1)
– lumbricals 1 and 2 (digits 2-3)
*** Consider major grip power driven by median nerve being the lateral hand (digits 1-3) in flexion and opposition.
Grip Muscles driven by ulnar nerve:
– flexor digitorum profundis (digits 4-5)
– flexor digit minimi brevis (digit 5)
– lumbricals 3 and 4 (digits 4-5)
– adductor pollicis (digit 1)
– opponens digit minimi (digit 5)
– palmar interossei for adduction (digits 2, 4, 5)
*** Consider major grip power driven by ulnar nerve being the medial hand (digits 4-5) in flexion and opposition and adduction of digits 1,2,4,5.
Grip Muscles driven by radial nerve: 0
**** Consider radial nerve-innervated extensors to possibly override median and ulnar nerve – innervated structures in grip.
Some rules of grip:
1. If BOTH sides of a grip/nerve pathway show weakness, the person is missing intrinsic abdominal stability. This same compensator for grip is likely the compensator for an intrinsic abdominal muscle (I.e., pelvic floor, multifidus, transversus abdominis, internal abdominal oblique).
Ex: Bilateral median nerve pathway weakness on grip testing has a common compensation: scalenes overriding core strength. This causes stretching across the brachial plexus in the neck, resulting in grip loss.
2. If ONE side of both median and ulnar nerve pathways are weak on grip testing, a muscle is overworking most likely in the axilla or neck. (These are the two places where the nerves get impinged together.)
Example: Right side median and ulnar grip loss caused by impingement of nerves at the coracopectoral tunnel by pectoralis minor or coracobrachialis.
3. If one side of one hand is weak on grip testing, the overworking structure is likely along the nerve pathway for impingement, or by an antagonist.
Example: Ulnar grip weakened by Tunnel of Guyon, flexor carpi ulnaris (FCU), medial brachial septum, scalenes, pectorals, etc.
When looking for your overriding structure:
– Palpate for tightness in a muscle associated with that nerve pathway.
– Consider the above rules.
When assigning grip correctives:
– Do NOT give a ball or a kettlebell and let the client grip as usual. They may use only their strong side!
Focus on the missing grip aspect as a priority.
Example: If FCU is impeding ulnar nerve function, consider assessing and treating FCU before working on the ulnar side of grip.
Dynamometer measurements were taken in our volunteers before and after grip work was assigned.
Major findings:
1. If the ulnar side of grip was inhibited on one side, FCU tended to be the impingement site.
Ex: One volunteer improved L grip by 20 pounds with this correction.
2. If bilateral grip was inhibited, the core musculature was assessed for overriding structures in the neck.
Ex: One attendee improved grip by 20 pounds by not even training grip but clearing an overworking scalene for a lazy abdomen.
80% of dynamometer measurements improved after the release of the impingement to grip.
Simply working the grip muscles is not enough.
If their neurological supplies are being impinged, help free the pathway with proper assessment.
Then, assign grip corrections specific to the client.
If you’d like to learn more about grip testing and hunting for impingements to it, consider taking a NeuroKinetic Therapy seminar near you!
As always, it’s your call.
– Dr. Kathy Dooley