Nerve Injuries

Injuries:

1. Paralysis

   1. complete inhibition of sensory and motor information to an area

2. Paresis

   1. partial inhibition

3. the more distal the injuries

4. nerves damaged:

   1. Radial nerve damage

      1. caused by a fracture of the humerus

      2. symptoms: wrist drop, inability to extend forearm and wrist, and loss of sensation

   2. Axillary nerve damage

      1. can be caused by shoulder dislocation

      2. symptoms: paralysis of deltoid and teres minor, loss of sensation, and inability to abduct the shoulder

   3. median nerve damage

      1. can be caused by carpal tunnel syndrome (compression and inflammation due to flexor retinaculum)

      2. symptoms: difficulty flexing the wrist, weak thumb movements, and inability to pronate. (ape hand: first two fingers are extended)

   4. Musculocutaneous nerve damage

      1. symptoms: loss of flexion of the forearm

   5. Ulnar nerve damage

      1. symptoms

         1. inability to adduct/abduct fingers, weakness flexing wrist, “claw hand”

   6. Brachial plexus

      1. Erb-Duchenne paralysis

         1. caused during delivery due to excess pulling on the neck of the baby

         2. It stretches or tears the superior trunk (C5 and C6)

         3. Symptoms: (waiter tip hand) arm is medially rotated and adducted at shoulder, extended at elbow, and pronated. Paralysis of Biceps (due to musculocutaneous), supinator (due to radial nerve), wrist extensors (due to radial nerve), deltoid muscles (due to axillary nerve)

      2. Klumpke’s paralysis

         1. due to birth paralysis due to pulling on the arm which affect C8 and T1 (ulnar nerve)

         2. Symptoms: “Claw hand". Paralysis of flexors of forearm and small muscles of hand.

      3. Crutch palsy

         1. Excessive use of crutches which may compress posterior cord

         2. affects the radial and axillary nerve

      4. Dermatome

         1. area of skin whose innervation is supplied by one pair of nerves (if nerve affected skin is affected in certain areas)

      5. A fracture of the olecranon process could result in which of the following?

         Inability to abduct/adduct fingers (c0rrect answer)

         Loss of thumb/finger opposition

         Inability to extend wrist

         Wrist drop

      6. Which muscle is innervated by the radial nerve?

         A biceps brachii

         B pronator

         C extensor carpi radialis longus (Correct answer)

         D all of the above

         None of the above

   7. Lumbar/Sacral Plexus

      1. Lumbar plexus

         1. derived from roots T12-L4

         2. nerves affected

            1. Femoral nerve innervates anterior compartment of thigh

               1. affects the quadricep femoris muscles (Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius) sartorius (allows you to cross your legs) and iliopsoas (hip flexors)

            2. Obturator nerve innervates medial compartment of thigh

               1. adductor magnus, adductor longus, adductor brevis, pectineus, and gracilis

         3. Damage to lumbar plexus

            1. causes: hemorrhage, compression, pelvic fracture, or fascial entrapment due to exercise

            2. types of never damage:

               1. obturator nerve damage

                  1. symptoms: loss of adduction and internal rotation of hip. possible pain in medial thigh

               2. Femoral nerve damage

                  1. damage would result in an inability to extend leg and loss of sensation

      2. Sacral plexus

         1. L4-S4

         2. gives rise to sciatic nerve (largest nerve)

         3. Sciatic nerve innervates flexors of the thigh (hamstrings)

         4. Tibial Nerve

            1. Innervates posterior compartment of leg (gastrocnemius &s soleus)

         5. Superficial fibular nerve

            1. innervates lateral part of the leg (fibularis longus & brevis)

         6. Deep fibular nerve

            1. innervates anterior compartment of leg (tibialis anterior, extensor digitorum longus, extensor hallucis longus)

         7. Damage to sciatic nerve & branches

            1. dislocated hip, slipped disc, compression of piriformis

               1. symptoms: pain or loss of sensation from buttocks

            2. foot drop

               1. damage of deep fibularis nerve

            3. Everting foot problem

               1. damage to superficial fibular nerve

            4. Plantar flex (tip toe) problem

               1. damage to tibial nerve