UE Nerves Flashcards
What Cord does the Axillary nerve come off of?
Posterior Cord
What are the nerve roots of the Axillary Nerve?
C5-C6
What Muscles are supplied by the Axillary Nerve?
Teres Minor
Deltoid
What sensory nerve does the axillary nerve become? And what area does this supply?
Becomes the Upper Lateral Cutaneous Nerve of the arm
Supplies: Skin covering the lower half of the deltoid and upper part of the long head of the triceps.
Causes of injury to the Axillary Nerve? And effects injury can have?
- Dislocation of the shoulder
- Fracture of Surgical Neck of The Humerus
Effects:
- “Square shoulder” from deltoid muscle atrophy
- Sensory loss over lower half of deltoid
What Cord does the Radial nerve come off of?
Posterior Cord
What are the nerve roots of the Radial Nerve
C5
C6
C7
C8
T1
What bony landmark does the radial nerve travel down?
Radial Groove of the Humerus
What space does the radial nerve exit the axilla?
Triangular Interval/Hiatus
What muscles are innervated by the Radial Nerve?
Triceps
Anconeus
Brachioradialis
Supinator
All Wrist Extensors:
(Extensor Carpi Radialis Longus & Brevis, Extensor Carpi Ulnaris, Extensor Digitorum, Extensor Digiti Minimi, Extensor Pollicis Longus & Brevis, Extensor Indicis, Abductor Pollicis Longus)
Radial Nerve Sensory Supply
Lower Lateral Cutaneous Nerve of the Arm
- Skin of lower half of lateral side of arm
Posterior Cutaneous Nerve of the Arm
- Skin of back of the arm
Posterior Cutaneous Nerve of the Forearm
- Skin of back of forearm
Superficial Branch
- Skin of lateral half of dorsum of hand,
lateral two and half digits including thumb (palmar aspect as well)
Causes of injury to the Radial Nerve? And effects injury can have?
Radial nerve can be injured in axilla,
musculospiral groove, around radial neck
Midshaft Humeral Fractures
Can lead to:
Radial tunnel syndrome
Posterior Interosseous Nerve (PIN) Syndrome
Wrist Drop! (due to injury proximal to the elbow)
What cord does the Ulnar Nerve come off of?
Medial Cord
What are the Nerve Roots of the Ulnar Nerve?
Main contribution (C8-T1)
What structure does the ulnar nerve travel through when entering the hand?
Tunnel of Guyon
What muscle does the ulnar nerve pierce when entering the forearm?
Flexor Carpi Ulnaris (Humeral and Ulnar Heads)
What muscles does the Ulnar Nerve Supply?
Dorsal Interossei (DAB)
Palmar Interossei (PAD)
Adductor Pollicis
A: Abductor Digiti Minimi
F: Flexor Digiti Minimi
O: Opponens Digiti Minimi
Flexor Digitorum Profundus (Medial Half)
Flexor Carpi Ulnaris
Lumbrical (3 and 4)
What is the Sensory supply of the Ulnar Nerve?
Supplies the 1/2 of 4th digit and 5th digit
What cords form the Median nerve?
Medial and Lateral Cords
What are the nerve roots of the Median Nerve?
C5
C6
C7
C8
T1
Which muscle does the Median nerve travel between when entering the forearm?
Enters forearm between two heads of the pronator teres
What structure does the Median Nerve Travel through entering the hand?
Carpal Tunnel
What is the Median Nerve Motor Supply?
Flexor Digitorum Profundus (Radial half)
Flexor Pollicis Longus
Pronator Quadratus
Abductor Pollicis Brevis
Pronator Teres
Opponens Pollicis
Palmaris Longus
Lumbricals 1,2
Flexor Carpi Radialis
Flexor Digitorum Superficialis
Flexor Pollicis Brevis
Median Nerve Sensory Supply?
Dorsal tips of 1st, 2nd and 3rd digits
Palmar skin of 2nd, 3rd, lateral half of 4th digits
What kind of hand deformity is associated with ulnar nerve injury?
Partial Claw Hand Deformity
Hyperextension of 4th, 5th MCP
Flexion at 4th, 5th IP
What kind of hand deformity is associated with Median Nerve injury?
Ape Hand Deformity
Wasting of thenar eminence, as a result of median nerve palsy
What Cord does the Musculocutaneous nerve branch off of?
Lateral Cord
What are the nerve roots of the Musculocutaneous Nerve?
C5
C6
C7
What is the Motor supply of the Musculocutaneous Nerve?
Biceps
Brachialis
Coracobrachialis
What sensory nerve does the Musculocutaneous nerve become and what does this nerve supply
Lateral Antebrachial Cutaneous Nerve of Forearm
- Supplies the skin on the lateral side of forearm
What trunk does the Suprascapular Nerve Arise from?
Upper/Superior Trunk
What are the nerve roots of the Suprascapular Nerve?
C5-C6
What is the Motor Supply of the Suprascapular Nerve
Supraspinatus
Infraspinatus
What portion of the brachial plexus does the Upper and Lower Subscapular Nerve arise from?
Posterior Cord
What are the Nerve Roots of the Upper and Lower Subscapular Nerves?
C5
C6
Motor Supply of the Lower Subscapular Nerve?
Subscapularis
Teres Major
Motor Supply of the Upper Subscapular Nerve
Subscapularis
What cord the lateral pectoral nerve?
Lateral Cord
What are the nerve roots of the Lateral Pectoral Nerve
C5
C6
C7
Lateral Pectoral Nerve Motor Supply
Pectoralis Major
- Clavicular Fibers; Shoulder Flexion
- Sternocostal Fibers: Shoulder Extension
What cord does the Medial Pectoral Nerve come off of?
Medial Cord
Nerve Roots of the Medial Pectoral Nerve?
C8
T1
Motor supply of the Medial Pectoral Nerve
Pectoralis Minor
What are the nerve roots of the Long Thoracic Nerve?
C5
C6
C7
What is the motor supply of the Long Thoracic Nerve
Serratus Anterior
What can injury to the Long Thoracic Nerve cause?
Winged Scapula aka Scapular Winging
What cord does the Thoracodorsal Nerve come off of?
Posterior Cord
What are the Nerve roots of the Thoracodorsal Nerve?
C6
C7
C8
Motor Supply of the Thoracodorsal Nerve?
Latissimus Dorsi
What is the nerve roots of the Dorsal Scapular Nerve?
C5
What is the Motor Supply of the Dorsal Scapular Nerve?
Rhomboids Major and Minor
Levator Scapulae
What trunk does the Nerve to Subclavius come off of?
Superior/Upper Trunk
What motions are impaired with damage to the Axillary Nerve?
Shoulder Abduction
and
External Rotation
What is a differentiating factor between Carpal Tunnel Syndrome and Compression of the Median Nerve with hypertrophy of the Pronator Teres?
Forearm muscles are involved such as the (pronator teres, wrist flexors and extrinsic finger flexors)
(Not just intrinsic muscles of the hand)
What ligaments covers the Carpal Tunnel?
Transverse Carpal Ligament
What Nerve is compressed with “Saturday Night Palsy” and how does this occur?
Occurs when a person is sleeping with their head on the arm that is slung over the back of a chair or open car window.
Radial Nerve
Does injury to the wrist or hand cause motor weakness to muscles supplied by the Radial Nerve?
NO
- Radial nerve enters the wrist as the superficial radial nerve, which is SENSORY ONLY
Is motor function affected in PIN syndrome?
No, Because the superficial sensory radial nerve has no motor innervation.
What is affected in AIN syndrome? What can differentiate this from CTS?
No sensory components, purely motor is affected
absence of sensory deficits in AIN syndrome differentiates it from carpal tunnel syndrome
