Nerves Flashcards
Long Thoracic Nerve
Spinal Segments: VR of C5 - C7
Course: Descends posterior to C8 and T1 roots, running inferiorly
on superficial surface of Serratus Anterior
Muscles: Serratus Anterior
Associated Arteries: Lateral Thoracic Artery
Dorsal Scapular Nerve
Spinal Segments: VR of C5
Course: Pierces middle scalene and descend inferiorly along the medial border of the scapula
Muscles: Rhomboid Major and Minor, Levator Scapulae
Associated Arteries: Dorsal Scapular Artery
Suprascapular Nerve
Spinal Segments: VR of C5 - C6
Course: Pases through posterior triangle of neck superior to the BP; goes underneath the transverse scapular ligament (scapular notch)
Muscles: Supraspinatus and Infraspinatus
Associated Arteries: Suprascapular artery
Nerve to Subclavius
Spinal Segments: VR of C5 - C6;
Course: coming from Superior Trunk, descends posterior to the clavicle and anterior to the BP
Muscles: Subclavius
Associated Arteries: Subclavian Artery
Lateral Pectoral Nerve
Spinal Segments: VR of C5 - C7
Course: Comes of lateral cord of the brachial plexus and passes over axillary artery and through coracoclavicular fascia and distributes innervation to the deep side of the pectoralis major
Muscles: Pectoralis Major
Associated Artery: Pectoral Branch of Thoracoacromial Trunk, off the axillary artery
Musculocutaneous Nerve
Spinal Segments: VR of C5 - C7
Course: Exits axilla and pierces Coracobrachialis; descends between the biceps brachii and brachialis, emerging in the cubital fossa.
Branches - Lateral Cutaneous Nerve of Forearm - Emerges lateral side of cubital fossa, proximal to biceps tendon and behind cephalic vein and splits into two branches
Muscles: Anterior Compartment of the Arm (Coracobrachialis, biceps brachii, and brachialis) and lateral cutaneous of the forearm
Associated Arteries: Brachial artery (arm) and radial artery (forearm)
Median Nerve
Spinal Segments: VR of C6 - T1
4 Branches: Main, Anterior Interosseous Nerve, Palmar Cutaneous Branch, Recurrent Branch
A. Main Branch
Muscles:
- Pronator Teres
- Flexor Carpis Radialis
- Palmaris Longus
- Flexor Digitorum SuperficialisPathway
Pathway:
Courses from lateral and medial cords of brachial plexus into the cubital fossa with the biceps tendon and brachial artery and goes to pronator teres then courses between FDS and FDP with ulnar artery . Enters the hand through the carpal tunnel deep to the flexor retinaculum along with the tendons of the FDS and FDP, as well as a little pocket for the FPL
B. Anterior Interosseous Nerve
- Flexor Digiturum Profundus (2 & 3 digits)
- Flexor Pollicis Longus
- Pronator Quadratus
Pathway
Runs with AIA between FPL and FDP and then deep to PQ
C. Palmar cutaneous branch
- Sensory to lateral aspect of the palm
Pathway:
Branches Proximal to carpal tunnel (not harmed during carpal tunnel syndrome)
D. Recurrent branch of Median Nerve
1/2 LOAF
- Lumbricals 1&2
- Opponens Pollicis
- Abductor Pollicis Brevis
- Flexor Pollicis Brevis
Pathway:
Branches off median after it comes out of carpal tunnel, heads superficially to the thenar muscles
E. Lateral/Median branches -> Common palmer digitals -> proper palmar digitals
- Skin of Thenar half of palm
- Palmar aspect of first 3 ½ digits,
- Nail bed of first 3 ½ digits
Medial Pectoral Nerve
Spinal Segments: VR of C8 - T1
Course: Passes between axillary artery and vein and pierces pectoralis minor and enters deep surface of pec major (actually lies lateral to the LPN)
Muscles: Pec Major and Pec Minor
Associated Arteries: Pectoral branch of thoracoacromial artery
Medial Cutaneous Nerve of the Arm
Spinal Segments: VR of C8 - T1
Course: Runs along medial side of axillary and brachial veins
Innervation: Medial cutaneous arm, all the way to the medial epicondyle of humerus
Medial Cutaneous Nerve of Forearm
Spinal Segments: VR of C8 - T1, off of medial cord
Course: Initially runs with Ulnar n, but peirces deep fascia with basilic vein and divides into anterior and posterior branches
Innervation: medial skin of forearm, as far distal as the wrist
Ulnar
Spinal Segments: VR of C8 - T1
Course: Descends along the medial arm, running posterior to the medial epicondyle (“funny bone”)
Innervation:
Motor: 1.5 muscles of anterior compartment of forearm not supplied by median nerve (Flexor Carpi Ulnaris (FCU), Ulnar half of Flexor Digitorum Profundus (FDP))
Sensory: skin to hand medial to axial line of 4th digit
Upper Subscapular
Spinal Segments: VR of C5 - C6
Course: Comes off of the posterior cord, passing posteriorly, entering the subscapularis directly
Innervation: Superior portion of subscapularis
Associated artery: subscapular artery
Lower Subscapular
Spinal Segments: VR of C5 - C6
Course: Passes inferolaterally off of the posterior cord, deep to subscapular artery
Innervation: inferior portion of subscapularis and teres major
Associated artery: subscapular artery
Thoracodorsal
Spinal Segments: VR of C6 - C8
Course: Arises from posterior cord, between U and L subscapular nerves, running inferolaterally along posterior axillary wall to latissimus dorsi
Innervation: Latissiumus Dorsi
Axillary Nerve
Spinal Segments: VR of C5 - C6
Course: Quadrangular space with posterior circumflex humeral artery; sends branches into deep surface of deltoid and posterior side of teres minor
Innervation:
Motor: Teres Minor and Deltoid
Sensory: skin of superolateral arm
Associated Artery: Posterior Circumflex humeral artery
Radial Nerve
Spinal Segmetns: VR of C5 - T1
Course: Arises from Posterior Cord, passing posterior to humerus in the radial groove with profunda brachial artery (in lateral triangular space), between the lateral and medial heads of the triceps; travels through cubital fossa, and divides into superficial (cutaneous) and deep (motor) branches. Deep branches into the PIN
Passes anterior to the lateral epicondyle (ie lateral epicondylitis = tennis elbow)
Innervation:
Motor: All muscles of posterior compartments of arm and forearm
Sensory:
- Posterior and inferolateral arm,
- posterior forearm,
- dorsal surface of hand lateral to digit 4
What are the branches of the median nerve and what do they innervate in the hand?
- Median N Proper
- 1st and 2nd lumbricals
- Recurrent Branch - MOTOR
- branches off distal to FRetinaculum (thus affected by carpal tunnel)
- innervates thenar muscles (OAF thumb)
- Lateral Branch - MOTOR and SENSORY
- innervates 1st lumbrical
- sensory to thumb and radial half of 2nd digit
- Medial Branch - MOTOR and SENSORY
- innervates 2nd lumbrical
- skin of 2 - 4 digits
- Palmar Cutaneous Branch - SENSORY
- arises proximal to Flexor retinaculum
- sensory to palm - NOT affected by carpal tunnel
What are the 4 branches of the ulnar nerve
- Palmar Cutaneous
- branches proximal to flexor retinaculum
- same sensory/motor test as carpal tunnel is for median, except this is for canal of guyon
- innervates skin at base of palm over medial carpals
- branches proximal to flexor retinaculum
- Dorsal Cutaneous
- Medial back of hand
- Superficial Branch
- Innervates palmaris brevis
- Palmar medial innervation
- Deep Branch
- Motor to everything except LOAF thumb
- 3/4LOAF pinky
- hypothenar
- Interossei
- Motor to everything except LOAF thumb
Describe the general regions of sensory innervation to the hand.
- Dorsal
- Superficial branch of Radial and dorsal cutaneous branch of the ulnar nerve
-
Dorsal fingernails of digits 2 and 3 are branches of palmar cutaneous of median n
- Palmar cutaneous branch of median N. is the only nerve that “comes over the fingertips” and innervates both palmar and dorsal
- Palmar
- Palmar cutaneous branch of ulnar, palmar cutaneous branch of median, and Superficial branch of radial n (at the very lateral edge)
What is the 1 branch of the radial nerve in the hand and what is its function?
- Superficial Branch of Radial - sensory to radial 1/2 of dorsal hand
- Imprtant Branches
- Common Dorsal Digital
- Proper dorsal digital
