ANAT102 week 5

Radial nerve lesion

Functional motor loss

• no weight bearing on upper limb

• cannot release grip

Deformity

• wrist drop

Ulnar nerve lesion

Functional motor loss

• loss of digital sweep on medial 2 digits (loss of intrinsic muscles)

• reduced power grip

Deformity

• claw hand - lumbricals, interossei and FDP not working, digit pulled by ED and FDS

Medial nerve lesion

Functional motor loss

• loss of digital sweep for lateral 2 digits (loss of lumbricals)

• reduced precision grip

Deformity

• ape hand (loss of thenar eminence)

• carpal tunnel

Suprascapular nerve lesion

Functional motor loss

• reduced ability to “seat” humeral head (head moves forward during all shoulder motion)

• reduced range of shoulder motion, particularly abduction and external rotation

  (inability to use all of glenoid surface)

  
  

Long thoracic nerve lesion

Functional motor loss:

• reduced scapulothoracic joint stability

• implications on scapulohumeral rhythm

Deformity

• winged scapula

Myotomes

Dermatomes

C5

• anterior shoulder

• middle anterior arm and forearm

C6

• lateral shoulder, arm, forearm

• thumb, thenar eminence

C7

• middle posterior shoulder, arm, forearm

• anterior surface of digits 2 and 3

C8

• medial forearm

• posteromedial arm

• digits 4 and 5

T1

• anteromedial arm

• middle anterior forearm