PNS 3 - Median Nerve Flashcards
Muscles Innervated
Flexor Carpi radialis, palmaris longus, pronator quadratus, pronator teres, digital flexors
Motor Functions
Thumb extension and opposition, flexion of digits 2 & 3, wrist flexion and abduction, forearm pronation
Sensory
Skin over anterolateral surface of hand
Common injury sites for Median Nerve at the shoulder
- Dislocation, usually anterior
- Direct trauma, some fractures
Common injury sites for Median Nerve at the arm
Fracture of the lower 1⁄4 of the humerus
Common injury sites for Median Nerve at the elbow
- Dislocation with anterior displacement, medial epicondylar fracture
- Closed reduction of elbow dislocation leading to intra-articular entrapment.
Common injury sites for Median Nerve at the forearm
- Fractures
- Anterior aspect blows, lacerations
- Entrapment beneath FDS
Median nerve can be entrapped in the space between the superficial and deep heads of the pronator teres muscle. This relates to what syndrome?
Pronator teres syndrome
Causes of Pronator teres syndrome
Elbow trauma, repetitive elbow flexion, supination and pronation of forearm
Signs/symptoms of Pronator Teres syndrome?
Chronic forearm pain/aching especially with pronation of forearm and paraesthesias in the median nerve cutaneous supply.
Wrist (most common site of median nerve injuries)
- Suicide attempts
- Fractures, dislocations, some sprains
Compression of the median nerve as it passes through carpal tunnel beneath the transverse carpal ligament. AKA what syndrome?
Carpal tunnel Syndrome
The carpal tunnel is a fibro-osseous tunnel formed by: Laterally?
tubercles of the scaphoid and trapezium
The carpal tunnel is a fibro-osseous tunnel formed by: medially?
pisiform and hook of the hamate
The carpal tunnel is a fibro-osseous tunnel formed by: Dorsally?
carpal bones
The carpal tunnel is a fibro-osseous tunnel formed by: Volarly
flexor retinaculum (transverse carpal ligament)
Motor: ORDER OF INNERVATION by Median Nerve
- Pronator Teres
- Palmaris Longus
- Flexor Carpi Radialis
- Flexor Digitorum Profundus (radial 1/2)
- Flexor Pollicis Longus
- Pronator Quadratus
- Abductor Pollicis Brevis
- Opponens Pollicis
- Flexor Pollicis Brevis (superficial 1/2)
- Lumbricals 1 and 2 (MCP flexion at digits 2 and 3)
Forearm pronation
SOLE: 2 muscles innervated?
Pronator Teres and Pronator Quadratus
Wrist flexion with median nerve is shared with what other nerve?
Ulnar Nerve
Wrist flexion with median nerve is shared with what other nerve? What 4 mm do they innervate?
Flexor Carpi Radialis, Flexor Pollicis Longus, Flexor Digitorum
Superficialis (Sublimis), Flexor Digitorum Profundus (Lateral 1⁄2)
Wrist Abduction with the median nerve is also share with what other nerve?
RADIAL Nerve
Wrist Abduction with the median nerve also shared with RADIAL, what muscle do they innervate?
Flexor Carpi Radialis
Median nerve and Thumb Opposition, what muscle?
Opponens Pollicis
Median nerve Finger Flexion SOLE: Fingers 2 and 3
lateral 1⁄2 Flexor Digitorum Profundus, Flexor Digitorum Superficialis, Lumbricals 1 and 2
Median nerve Finger Flexion shared with this nerve for fingers 4-5?
Ulnar nerve
Median nerve Finger Flexion shared with Ulnar for fingers 4-5. What muscle?
Flexor Digitorum Superficialis
SENSORY
Area of isolated supply (SOLE):
anterior and posterior aspect of distal tips of
fingers 2 and 3
Primary Zone for Median Nerve: Anterior:
Lateral 2/3 of hand (boundaries include midline of 4th digit, wrist line – excluding distal tips of digits 2 and 3)
Posterior:
Distal 2/3 fingers 2 and 3, lateral 1⁄2 finger 4 excluding tips of digits 2 and 3.
AUTONOMICS T/F
Median Nerve carries majority of autonomic fibres for entire arm, forearm and hand.
True
Median Nerve PROPRIOCEPTION is responsible for all of this digits movements?
Thumb
Median Nerve PROPRIOCEPTION is responsible for flexor surfaces of fingers ____ and ____ and lateral aspect of _______ joint?
2 and 3
Wrist joint
The median nerve is referred to as the
“________ ________” nerve.
tool utilization
Median nerve testing
- Rule out C-spine and TOS
- Neural tension test
- Muscle tests: pronator teres, Flexor Digitorum Superficialis (Flexion at DIPs), Thumb opposition. flexion and Abductor pollicis brevis (thumb abduction at the proximal phalanx)
- Special tests: Phalen’s Test and Reverse Phalen’s test, Tinel’s sign at the wrist, Pinch test (O.K sign)
