NEURO: Part 9 Flashcards
WHat nerves contributes to the median nerve
C5-7, C8 + T1
What muscles of the forearm are innervated by the median nerve
- Palmaris longus
- Flexor capri radialis
- Flexor digitorum superficialis
What does the anterior interosseous branch of the median nerve supply
- Flexor policis longus
- Lateral half of flexor digitorum profundus
- Pronator quadratus
What does the palmer cutaenrous branch of the median nerve supply
Sensory innervation to thenar eminence of palm
Median nerve innervation of the hand
- Flexor digitorum superficialis
- Flexor digitorum profundus
- Flexor pollicis longus
Recurrent branch:
- opponens pollicis
- Abductor pollicis brevis
- Flexor pollicis permis
What do the cutaneous branch of the median nerve supply
- Lateral 3 and a half
What is Anterior interosseous syndrome
—- Reminder —–
1. Flexor policis longus
2. Lateral half of flexor digitorum profundus
3. Pronator quadratus
—————————-
Loss of pronation of forearm
Loss of flexion of radial half of digits and thumb
NO SENSORY LOSS
What causes anterior interosseous syndrome
Tight Cast
Forearm bone fracture
Result of damaging the wrist
MOTOR DEFICIT:
- Weakness in flexion of the radial half of digits and thumb
- Loss of abduction and opposition of the thumb
APE HAND DEFORMITY seen (hyperextension of index and thumb)
Benediction sign seen
SENSORY:
Loss of sensation in lateral 3 1/2 digits including nail beds
What is the benediction sign
Patients can flex all fingers EXCEPT the index finger
Innervation of the lubricals
Lateral two = lumbrical
Medial two = ulnar
What doe the ulnar nerve supply when it branch sin the forearm
- Medial half of flexor digitorum profundus
- Flexor carpi lunaris
- Medial half sensory sensation to digits (1 and a half)
What does the ulnar supply in the hand when it branches
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
Roots of the ulnar nerve
C7-T1
What causes damage commonly to the ulnar nerve at there elbow
- Cubital tunnel syndrome
2. Fracture of medial epicondyle
Clinical presentation of ulnar damage at the elbow
MOTOR DEFICIT:
1. Weakness in flexion of hand AT THE WRIST
2. Loss of flexion in ulnar half of digits
3. CLAW HAND deformity when hand is at rest
4. Weakness of adduction o the thumb
5. Interossei muscle wasting means patient can’t do good luck sign
——SENSORY——–
Loss of sensation and paraesthesiae in ulnar half of palm and back of hand
Medial 1 and 1/2 digits on both palmar and dorsal aspects of the hand
How do we assess weakness of adduction o the thumb
Look for FROMENT’s Sign
What is Froment’s sign
Difficult maintaining a hold on an object (digits minimi oppenens is not working so will try compensate by flexing policies longs more)
What usually causes damage to ulnar nerve at the wrist
- WOUNDS
Clinical presentation of ulnar damage at the wrist
- —-MOTOR_—–
1. Loss of flexion in ulnar half of the digits
1. CLAW HAND deformity when hand is at rest (more prominent than in elbow)
——SENSORY——-
Loss of sensation and paraesthesiae in ulnar half of palm, medial 1 1/2 digits and the DORSAL is spared
Why is CLAW HAND DEFORMITY more prominent in wrist injuries to the ulnar
Ulnar half of flexor digitorum profundus is not affected so they pull interphalangeal joints of 4th and 5th digit into flexion whilst the lateral three digits are straight
Why is the dorsal part of the hand spared in wrist damage to ulnar nerve
Because the posterior cutaneous branch of the ulnar nerve is given off higher up the forearm
How is Ulnar nerve palsy treated
Night splint and rest
Roots of the radial nerve
C5 - T1
What does the radial nerve supply in the arm
- Brachialis
- Brachioradialis
- Extensory carpi radialis longus
- Suppinators
SENSORY: Supplies skin at back of the arm
What does the radial nerve supply in the forearm
Forms the posterior interosseous nerve:
- Extensor digitorum
- Extensor digit minimi
- Extensor carpi lunaris
- Abductor pollicis longus
- Extensor pollicis brevis
- Extensor pollicis longus
- Extensor indicis
Common causes of injury to the radial nerve at the axilla
- Saturday NIGHT PALSY
2. Crutch palsy
What is Saturday night palsy
Caused by:
Another individual sleeping on one’s arm overnight
Falling asleep with one’ arm hanging over arm rest chair compressing nerve
Squash
Common injury to the radial nerve at the mid-arm
- MID-SHAFT humeral fracture
Clinical presentation of radial nerve damage at th mid-arm
- Weakness of supination and loss of hand extension and fingers (test by flexing elbows and arm pronated)
- Presence of WRIST DROP due to inability to extend hand and fingers
——-Sensory———
Loss of sensation in posterior forearm
Radial dorsal of the hand
Dorsal radial 3 and a half digits
Causes of damage to the brachial plexus
- Trauma
- Radiotherapy
- Prolongues wearing of heavy rucksack
- Neuralgic amyotrophy
- Thoracic outlet compression
Clinical presentation of brachial plexus
- Pain/paraesthesiae and weakness in affected arm in variable distribution
Clinical presentation of phrenic palsy
ORTHOPNOEA
Raised hemidiaphragm on CXR
What causes phrenic palsy
- Lung cancer
- Myeloma
- Thymoma
- Cervical spondylosis
- Phrenic nucleus lesion in MS
- Thoracic surgery
- HIV
- Muscular dystrophy
Roots of lateral cutaneous nerve of the thigh
L2 and L3
Clinical presentation of lateral cutaneous nerve palsy
Anterior-lateral burning of thigh from entrapment under inguinal ligament