Nerves & Dermatomes Flashcards
What are the 6 nerves of the upper limb?
Musculocutaneous nerve
Radial nerve
Median nerve
Ulnar nerve
Long thoracic nerve
Which nerve roots supply the musculocutaneous nerve?
C5-C7
Which nerve roots supply the axillary nerve?
C5 and C6
Which nerve roots supply the radial nerve?
C5-C8
Which nerve roots supply the median nerve?
C6, C8, and T1
Which nerve roots supply the ulnar nerve?
C8 and T1
Which nerve roots supply the long thoracic nerve?
C5-C7
Which nerve supplies the motor function for elbow flexion (through the biceps brachii) and supination, aswell as sensation for the lateral part of the forearm?
Musculocutaneous nerve
Which nerve supplies the motor function of the deltoid muscle for shoulder abduction, aswell as sensation to the inferior region of the deltoid muscle?
Axillary nerve
By which mechanism is an axillary nerve injury sustained?
Humeral neck fracture/dislocation
Results in a flattened deltoid muscle.
Which muscles are supplied by the median nerve?
Lateral two lumbricals
Opponens pollis
Abductor pollis brevis
Flexor pollis brevis
Think ‘LOAF’.
How may a median nerve injury site differentiated between the wrist and elbow?
If at the wrist, there will be paralysis of thenar muscles and opponens pollicis.
If at the elbow, there will be loss of pronation, loss of forearm flexion, and weak wrist flexion.
What area of the body is supplied sensation by the median nerve?
The palmar aspect of the lateral 3.5 fingers.
What nerve is responsible for the motor function for wrist flexion, and sensation to the medial 1.5 fingers of the hand?
Ulnar nerve
Injury to which nerve will result in a wrist drop?
Radial nerve
Often results in a humeral midshaft fracture.
Which nerve may be impacted by a medial epicondyle fracture?
Ulnar nerve
Damage may result in a ‘claw hand’.
Which nerve supplies motor function to serratus anterior?
Long thoracic nerve
Damage results in a winged scapula.
How may long thoracic nerve injury present?
Sport - following a blow to the ribs.
Following mastectomy
Which shoulder injury may result from shoulder dystocia?
Erb-Duchenne’s Palsy
Due to damage of the brachial plexus at C5, C6.
Arm will hang by the side, internally rotated, with the elbow extended.
Which nerve palsy is associated with Horner’s syndrome?
Klumpke injury
Due to damage of the brachial plexus at C8, T1.
What are the 3 dermatomes of the hand?
C6 (thumb and index finger)
C7 (middle finger and palm of hand)
C8 (ring and little finger)
What area is the T4 dermatome located at?
Nipple
What area is the T6 dermatome located at?
Xiphoid process
What area is the T10 dermatome located at?
Umbilicus
What area is the L1 dermatome located at?
Inguinal ligament
What area is the L4 dermatome located at?
Knee cap
What area is the L5 dermatome located at?
Big toe
Dorsum of the foot
What area is the S1 dermatome located at?
Small toe
Lateral foot
What are the 7 nerves of the lower limb?
Femoral nerve
Lateral cutaneous nerve
Obturator nerve
Tibial nerve
Common peroneal nerve
Superior gluteal nerve
Inferior gluteal nerve
Which nerve supplies motor function for knee extension and thigh flexion, aswell as sensation to the anterior and medial aspects of the thigh and lower legs?
Femoral nerve
What form of injuries may result in femoral nerve damage?
Hip and pelvic fractures
Stab/Gunshot wounds
Which nerve is responsible for the motor aspect of thigh adduction, aswell as providing sensation to the medial thigh?
Obturator nerve
Which nerve does NOT provide any motor function to the lower limb?
Lateral cutaneous nerve of the thigh
What areas are provided sensory function by the lateral cutaneous nerve of the thigh?
Lateral and posterior surfaces of the thigh.
Which condition is associated with lateral cutaneous nerve of the thigh compression?
Meralgia paraesthetica
Results from compression near the ASIS.
What motor functions are provided by the tibial nerve?
Foot plantarflexion and inversion.
Which area is provided sensation by the tibial nerve?
Sole of the foot.
What sensory function is supplied by the superior gluteal nerve?
None
What nerve is responsible for hip extension and lateral rotation?
Inferior gluteal nerve
What sensory function is supplied by the inferior gluteal nerve?
None
What are the 4 muscles of the rotator cuff?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Which rotator cuff muscle is most commonly injured?
Supraspinatus
What is the role of supraspinatus?
Abducts the arm before the deltoid.
What is the role of the infraspinatus?
Rotates the arm laterally.
What is the role of teres minor?
Adducts the arm, and rotates the arm laterally.
What is the role of subscapularis?
Adducts the arm, and rotates the arm medially.
