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Upper nerve lesions
Nerve lesions of the upper limb
Question | Answer |
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* * What will injury to the axillary nerve cause? Muscle and sensation? What is a common way of injuring the axillary nerve? | paralysis of the deltoid muscle and teres minor, loss of cutaneous sensation over the lower half of the deltoid muscle; badly adjusted crutches or shoulder joint dislocations |
Pressure of badly adjusted crutches, fractures, and dislocation of the proximal humerus by a drunkard falling asleep with one arm over the back of the chair can harm what nerve/ | The Radial nerve |
What muscles are compromised in a radial nerve palsy? What actions are compromised? | Triceps, brachioradialis, supinator, and ALL EXTENSORS are paralyzed; inability to EXTEND elbow or wrist joint-->wristdrop (unopposed wrist flexors); supination still posible (biceps brachii) |
What sensory sensation is lost in a radial nerve palsy (at the axilar level)? | loss of sensation down posterior surface of the lower part of the arm and down narrow strip of the back of the forearm; sensory loss on th elateral part of the dorsum of the hand and dodrsal surface of the roots of the lateral 3.5 fingers |
A fracture of the shaft of the humerus or prolonged pressure on the back of the arm would most likely injure what nerve? What are the symptoms? | Cause injury in the radial nerve; wristdrop same, extension of the elbow may NOT be impaired (damage usually below triceps brachii); loss of sensation on the dorsal surface of the lateral part of the hand and dorsal surface of roots of lateral 3.5 fingers |
What would an injury of the median nerve at the elbow region cause? What could cause it? | Pronator muscles of the forearm and long flexor muscles @ WRIST and FINGERS (except flexor carpis ulnaris and medial 1/2 of flexor digitorum profundus) paralyzed, thenar muscles and 1st 2 lumbricals parazlyzed; suprachondylar fracture of the humerus |
How would a patient with a median nerve injury at the level present (muscle action)? | Forearm is kept supine (loss of pronators); wrist flexion is weak + accompanied by adduction (loss of flexor carpi ulnaris)-->hand of papal benediction + ape like hands; thumb is adducted; inability to oppose thumb |
What sensory loss would a patient with a median nerve injury at the elbow region present? | Skin sensation on the lateral half or less of the palm of the hand and the palmar aspect of the lateral three one and a half finers; sensory loss also occurs on the skin of the distal part of the dorsal surfaces of the lateral three and one-half fingers |
What is the most common site of injury of the median nerve? | The wrist, where it lies in the interval between the tendons of the flexor carpi ulnaris and the flexor digitorum superficialis, overlapped by the palmaris longus tendon |
What would you observe in a median nerve wrist injury? | Paralysis of the thenar muscles and the first two lumbricals; wasted thenar eminence; thumb is adducted; inability to oppose thumb; sensory losses would be same as those in elbow lesion |
What is the cause of carpal tunnel syndrome? | Caused by compression of the median nerve in the carpal tunnel (MOST COMMON COMPRESSION NEUROPATHY) |
What are the symptoms of carpal tunnel syndrome? | Burning pain or pins and needles along distribution of the median nerve to the lateral 3 1/2 fingers and weakness of the thenar muscles |
Would you expect to see sensory loss over the thenar eminence in carpal tunnel syndrome? | No (area is supplied by the palmar cutaneous branch of the median nerve, which passes superficially to the flexor retinaculum) |
An injury at themedial epicondyle of the elbow would likely hurt what nerve? | The ulnar nerve |
What would an ulnar nerve lesion result in (what muscles are compromised)? | Flexor carpi ulnaris, medial 1/2 of flexor digitorum profundus, small muscles of the hand EXCEPT the thenar muscles, and the first 2 lumbrical muscles |
What actions are impaired in an ulnar nerve lesion at the elbow level? | Flattening medial part of the forearm due to wasting of the flexor carpi ulnaris and the medial 1/2 of the flexor digitorum profundus; abduction and adduction of the fingers impossible (interosseous muscles); impossible to adduct thumb (adductor pollicis) |
What would a person with an ulnar nerve lesion at the elbow level look like? | Hyperextension of the knuckle joints due to unopposes action of the extensor digitorum due to paralysis of the interosseus muscles and lumbricals 3 and 4; flexion of interphalangeal joints (4th and 5th most prominent); hypothenar eminence wasted |
What sensory deficit would an ulnar nerve lesion at the elbow level cause? | Loss of sensation over the anterior and posterior surfaces of the medial third of the hand and medial one and one half fingers |
What would an ulnar nerve lesion at the wrist level cause? | Clawhand more obvious; marked flexion of the terminal phalanges; small muscles of hand paralyzed and show wasting EXCEPT for muscles of thenar eminence and first 2 lumbricals |
What would an ulnar nerve injury at the wrist cause in terms of skin sensation? | Anterior and posterior surfaces of the medial 1/3 of the hand and the medial 1 1/2 fingers |