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Orthopaedics
The Median Nerve
Built from Pillemer — Physical Signs in Orthopaedics and Neurology
What’s inside
8 sections · 63 slides
Overview
- What this deck teaches you
Anatomy
Where the nerve comes from and the path it takes to the hand
- Where the median nerve begins
- The median nerve
- Its journey down the arm
- Median nerve medial to the brachial artery
- Through the forearm: the tight spots
- Median nerve at the pronator teres and FDS arch
- Reaching the hand
- Motor and sensory branches of the median nerve
Function
The muscles it moves and the skin it feels
- Motor: what the nerve powers
- A memory hook for the hand muscles: LOAF
- Sensory: the skin it feels
- Sensory territory of the median nerve in the hand
- The palmar cutaneous branch
Testing motor function
Isolating one muscle at a time so a weak nerve cannot hide
- Two layers of muscle to test
- Testing the deep flexor (FDP)
- Isolating the deep flexor (FDP) action
- Testing flexor pollicis longus
- Testing the superficial flexor (FDS)
- Isolating the superficial flexor (FDS)
- Testing the hand (intrinsic) muscles
- Abduction of the thumb
- Opposition of the thumb
- Wasting of the thenar eminence
Testing sensory function
Reading the skin map of the hand and its 'autonomous zones'
- How three nerves share the hand
- How three nerves share the skin of the hand
- Autonomous zones: the give-away spots
- Autonomous zones of the hand nerves
- How to test sensation properly
- Three tricks for the unconscious patient or young child
- The violin test
- The violin test with tissue paper
- The prune test
Lesions of the median nerve
The common entrapment syndromes and how they present
- The three classic entrapment syndromes
- Carpal tunnel syndrome: the mechanism
- The carpal tunnel
- Carpal tunnel syndrome: symptoms
- Carpal tunnel syndrome: physical signs
- Tinel's sign
- Phalen's test
- Durkan's test
- Pronator teres syndrome
- Anterior interosseous nerve (AIN) syndrome
- The OK sign test
- Pulp pinch
- Other lesions worth remembering
- The Benediction sign
High versus low lesions
A distinction that saves patients from failed surgery
- Why this distinction matters
- High vs low median nerve lesion
- Reading the three distinguishing signs
- Loss of thumb-tip flexion in a high lesion
- Sensory loss in a high lesion
Summary
The essentials to carry to the bedside
- Key takeaways
- A patient has had two failed carpal tunnel releases yet still has median-type numbness. What must you check, and why?
- Physical Signs in Orthopedic and Neurologic Disorders: A Practical Guide