MSRA Orthopaedic Anatomy Flashcards
What are the nerve roots for the following reflexes:
Plantar, Ankle, Knee, Bicep, Tricep.
Plantar: (S1) Ankle S1, S2 Knee L3, L4 Bicep C5, C6 Triceps C7, C8
S1/S2 Pick up shoes
L3/L4 Kick the door
C5/C6 Pick up sticks
C7/C8 Tricep dips mate
Name the relevant dermatome: big toe and dorsum of the foot.
L5
Name the relevant dermatome: kneecap
L4 (down on all fours)
Name the relevant dermatome: lateral foot and little toe
S1
Name the relevant dermatome: lower thigh
L2 and L3
Name the relevant dermatome: inguinal ligament
L1
Name the relevant dermatome: umbilicus
T10 (belly but-‘ten’)
Name the relevant dermatome: trapezius and shoulder
C3, C4
Name the relevant dermatome: lateral arm and thumb
C5, C6
Name the relevant dermatome: medial arm
C8, T1
Name the relevant dermatome: S2, S3,
Genitalia and buttock
Sensory nerve supply of the hand:
Ulnar nerve: little finger and half of ring finger
Median nerve: tips and palmar aspect of thumb, 2nd and 3rd finger.
Radial: dorsal aspect of thumb 2nd and 3rd finger
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: femoral
Motor: knee extension and thigh flexion (straight leg raise)
Sensory: anterior aspect of the thigh and lower leg
Nerve root: L2,L3 and L4
Injury: pelvic/hip fractures, stab/gunshot wounds
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: obturator
Motor: Thigh adduction (moving thigh back to midline)
Sensory: Medial thigh
Nerve root: L2, L3, L4
Injury: Anterior hip dislocation
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: Tibial
Motor: Foot plantarflexion and inversion
Sensory: Sole of foot
Nerve root: L4-S3 (branch of sciatic so shares nerve roots)
Injury: Not commonly injured as deep and well protected.
Popliteal lacerations, posterior knee dislocation
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: common peroneal nerve
Motor: Foot dorsiflexion and eversion and extensor hallucis longus (big toe extension) aka foot drop
Nerve root: L4, L5, S1, S2
Sensory: Dorsum of the foot and the lower lateral part of the leg
Injury: often occurs at the neck of the fibula
Tightly applied lower limb plaster cast
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: superior glueteal nerve
Motos: Hip abduction
Sensory: None
Nerve root: L4, L5 S1
Injury: Misplaced intramuscular injection Hip surgery Pelvic fracture Posterior hip dislocation
Injury results in a positive Trendelenburg sign
When standing on one leg the pelvis drops on the opposite side
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: inferior gluteal nerve
Motor: Hip extension and lateral rotation
Sensory: None
Nerve root: L5, S1, S2
Injury: Generally injured in association with the sciatic nerve
Injury results in difficulty rising from seated position. Can’t jump, can’t climb stairs
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: lateral cutaneous nerve
No motor
Nerve root: L2, L3
Sensory: lateral and posterior aspect of the thigh
Injury: Compression of the nerve near the ASIS → meralgia paraesthetica (skinny jeans syndrome)
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: sciatic nerve
Motor: Foot drop and external rotation and abduction contracture of the hip
Sensory: Foot and lower leg (except medial aspect)
Nerve root: L4-S3 (not sciatic nerve splits into common peroneal and tibial)
Injury: Hip replacement, misplaced injections
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: Musculocutaneous nerve.
Root: C5-C7
Motor: Elbow flexion (supplies biceps brachii) and supination
Sensory: Lateral part of the forearm
Injury: Isolated injury rare - usually injured as part of brachial plexus injury
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: axillary nerve
Root C5,C6
Motor: Shoulder abduction (deltoid muscle)
Sensory: Inferior region of the deltoid muscle
Injury: Humeral neck fracture/dislocation
Results in flattened deltoid
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: radial nerve
Root: C5-C8
Motor: Extension (forearm, wrist, fingers, thumb) Small area between the dorsal aspect of the 1st and 2nd metacarpals. Palsy results in wrist drop.
Sensory: Humeral midshaft fracture
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: Median nerve
Roots: C6, C8, T1
Motor: LOAF muscles
Features depend on the site of the lesion:
Wrist: paralysis of thenar muscles, opponens pollicis
Elbow: loss of pronation of forearm and weak wrist flexion
Sensory: Palmar aspect and tips of lateral 3½ fingers
Injury: Wrist lesion → carpal tunnel syndrome
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: Ulnar nerve
Root: C8, T1
Motor: Intrinsic hand muscles except LOAF and wrist flexion
Sensory: Medial 1½ fingers
Injury: Medial epicondyle fracture
Damage may result in a ‘claw hand’
For the following nerve, describe the motor, sensory function, nerve root and possible mechanism of injury: long thoracic nerve
Root: C5-C7
Motor: Serratus anterior, damage results in a winged scapula
No sensory
Often during sport e.g. following a blow to the ribs. Also possible complication of mastectomy
What is Erb-Duchenne palsy?
Also known as ‘waiter’s tip’
Due to damage of the upper trunk of the brachial plexus (C5,C6) may be secondary to shoulder dystocia during birth the arm hangs by the side and is internally rotated, elbow extended.
What is Klumpke injury.
Due to damage of the lower trunk of the brachial plexus (C8, T1) as above, may be secondary to shoulder dystocia during birth.
Also may be caused by a sudden upward jerk of the hand associated with Horner’s syndrome
