Nerves - Upper Extremity Flashcards
(20 cards)
Spinal Accessory Nerve
CNXI
Runs deep to trapezius with the superficial branch of the transverse cervical artery
IMPORTANT: This nerve innervates trapezius - the only muscle of the upper extremity that does not receive its innervation from the brachial plexus
Supraclavicular Nerves
Sensory nerves in the pectoral region
Originate from the Cervical Plexus
Sensory innervation of the area over the clavicle and the superolateral part of pec major
Intercostal Nerves (T2 - T12)
Sensory nerves that form the dermatome banding pattern
T4 - level of nipples
T10 - Level of Umbilicus
Dorsal Scapular Nerve
Comes off the brachial plexus at the level of the RAMI
Origin: comes off C4 and C5 superiorly
Runs posteriorly along the medial border of the scapula with the dorsal scapular artery
Motor to levator Scapula and Rhomboids (Major and Minor)
Long Thoracic Nerve
Comes off the brachial plexus at the level of the RAMI; comes off C5, C6, and C7 inferiorly
Input: C5-C7
Goes behind C8 and T1, and runs inferiorly along the thoracic wall with the lateral thoracic artery towards serratus anterior
Motor to Serratus Anterior
Suprascapular Nerve
Origin: Superior Trunk of the Brachial Plexus
Input: C4, C5, C6
Comes off the superior trunk superiorly
Runs posteriorly towards the suprascapular notch where it runs below the transverse scapular ligament and into the supraspinous fossa (accompanied by the subrascapular artery which runs above the ligament).
It winds around the Spinoglenoid notch, and continues into the infraspinous fossa of the scapula
Motor to Supraspinatus and Infraspinatus
Sends a sensory branch to the glenohumeral joint
Nerve to Subclavius
Origin: Superior Trunk of the Brachial Plexus
Juts out straight forward toward the clavicle and runs parallel to the floor towards subclavius
Motor to Subclavius
Lateral Pectoral Nerve
Origin: Lateral Cord of the Brachial Plexus
Input: C5, C6, C7
Comes off the lateral Cord at the level of the thoracoacromial truck artery at the superior edge of pec minor
Runs around pec minor into the deep surface of pec major
Motor to Pectoralis Major
Musculocutaneous Nerve
Origin: Terminal Branch of the Lateral Cord of the Brachial Plexus
Input: C5, C6, C7
Pierces Coracobrachialis
Sits between the biceps brachii and brachialis muscles
Ends at the level of the elbow where it becomes the lateral antebrachial cutaneous nerve
Lateral Antebrachial Cutaneous Nerve emerges superficially lateral to the biceps between the biceps brachii and brachialis muscles; it sits on the brachialis muscle and descends in the subcutaneous tissue to the lateral aspect of the forearm until is is found superficially in the anatomic snuffbox
MC: Motor to the muscles of the anterior compartment of the arm
Lateral cutaneous: Sensory to the lateral aspect of the forearm
Upper Subscapular Nerve
Origin: Posterior Cord of the Brachial Plexus
Input: C5, C6
Runs straight to subscapularis muscle
Motor to subscapularis
Thoracodorsal Nerve
Origin: Posterior Cord of the Brachial Plexus
Input: C6, C7, C6
Runs inferiorly towards Latissimus Dorsi with the Thoracodorsal Artery
Motor to Latissimus Dorsi
Lower Subscapular Nerve
Origin: Posterior Cord of the Brachial Plexus
Input: C5, C6
Runs parallel to the subscapular artery as it branches off the axillary artery
Gives Motor branches to Teres Major and Subscapularis
Motor to: subscapularis and Teres Major
Axillary Nerve
Origin: Terminal Branch of the Posterior Cord of the Brachial Plexus
Input: C5, C6
Exits the axilla posteriorly
Found in the quadrangular space with the Posterior Circumflex Humeral Artery
Motor to Deltoid and teres minor
Sensory to GH joint
Gives a superior lateral cutaneous branch that is sensory to the area overlying the deltoid
Radial Nerve
Origin: Terminal Branch of the Posterior Cord of the Brachial Plexus
Input: C5, C6, C7, C8, T1
Found in the triangular interval with the profunda brachii artery
Motor to the Muscles in the posterior compartment of the arm.
Runs in the radial groove on the posterior surface of the humerus (with the profunda brachii artery)
Pierces the lateral antebrachial septum at the level of the lateral epicondyle and come to sit anteriorly between brachioradialis and brachialis
Spilts into superficial and deep branches behind brachioradialis
Deep branch winds around the head of the radius posteriorly, pierces the supinator, and becomes the posterior interosseous nerve; this branch is motor to the muscles of the posterior compartment of the forearm
Superficial branch runs deep to brachioradials, then peeks out superficially in the lateral third of the forearm on its way to the anatomic snuffbox. Passes superficially across the anatomic snuffbox and then branches into dorsal digital nerves that are sensory to the radial side of the dorsum of the hand (radial to the line bisecting the 4th digit and proximal to the distal phalanges)
Medial Pectoral Nerve
Origin: Medial Cord of the Brachial Plexus
Input: C8, T1
Pierces Pec Minor and runs through to Pec Major
Motor to Pec Major and Pec Minor
Almost always has a communicating branch with the Lateral Pectoral Nerve
Medial Brachial Cutaneous Nerve
Origin: Medial Cord of the Brachial Plexus
Input: C8, T1
Often joins the INTERCOSTOBRACHIAL NERVE (T1) on its way to the subcutaneous tissue of the arm.
Sensory to the medial aspect of the arm
Medial Antebrachial Cutaneous Nerve
Origin: Medial Cord of the Brachial Plexus
Input: C8, T1
Passes through the arm into the forearm
Initially runs with the ulnar nerve, but in the forearm it runs more superficially in the subcutaneous tissue
Sensory to the medial aspect of the forearm
Intercostobrachial Nerve
Origin: T2 (could be T1)
Comes from the T2 intercostal space of the thoracic wall and communicates with the medial brachial cutaneous nerve.
Sensory to the medial aspect of the arm.
Median Nerve
Origin: Formed by Branches of the Lateral and Medial Cords of the Brachial Plexus (forms the center of the M)
Runs anterior to the axillary artery then lateral to the brachial artery
Passes through the arm without supplying anything.
Passes in front of the brachial artery proximal to the cubital fossa, then they run together through the cubital fossa into the forearm
Passes BETWEEN THE HEADS OF PRONATOR TERES when it reaches the forearm
In the forearm, it is motor to Pronator Teres, FCR, Palmaris Longus, and FDS
Runs deep to FDS , and gives off a branch called the ANTERIOR INTEROSSEOUS NERVE, which runs along the interosseous membrane with the anterior interosseous artery. This branch is motor to the lateral part of FDP, Flexor Pollicis Longus, and Pronator Quadratus. The anterior interosseous nerve and artery pass between FDS and the tendon of FPL and descend medial to FPL in the forearm
Also gives off a palmar cutaneous branch proximal to the flexor retinaculum that goes into the center of the hand and is sensory to the palm of the hand radial to the line bisecting the 4th digit.
The continuing branch passes into the hand deep to the flexor retinaculum in the carpal tunnel. it gives off the following branches in the hand:
Recurrent branch - runs radially towards the thumb. Motor to all the thenar muscles except adductor pollicis and the deep head of flexor pollicis brevis
Medial and Lateral branches - motor to Lumbricals 1 and 2. Give off common proper digital branches which branch into proper palmar digital branches at the level of the MCP joints. These branches are sensory to the palmar surface of digits 1, 2, 3, and half of 4, and to the dorsal aspect of the distal phalanges of those digits
Ulnar Nerve
Origin: Terminal Branch of the Medial Cord of the Brachial Plexus
Input: C7, C8, T1
In the arm, it initially runs medial to the brachial artery and median nerve in the ANTERIOR compartment. It then turns posteriorly, piercing the medial intermuscular septum along with the superior ulnar collateral artery.
It runs behind the medial epicondyle into the posterior compartment of the forearm, where it passes BETWEEN THE HEADS OF FLEXOR CARPI ULNARIS
It runs deep to FCU with the ulnar artery in the forearm, where it is motor to FCU and the medial half of FDP
In the forearm (before Guyon’s canal) it gives off a dorsal branch that passes into the hand posteriorly. In the back of the hand, this branch spilts into dorsal digital branches. these branches and the dorsal branch are sensory to the medial dorsum of the hand and the dorsum of the 5th and medial half of the 4th digits
Continuing Ulnar N. Passes superficial to the flexor retinaculum and deep to the palmar carpal ligament through Guyon’s canal (between the pisiform and hook of the hamate) into the palm of the hand. When it reaches the palm, it gives a PALMAR BRANCH that is sensory to the skin on the medial palm (medial to the line bisecting the 4th digit)
Continuing ulnar nerve then spits into superficial and deep branches.
Superficial branch: spilts into common palmar digital branches and then proper palmar digital branches that are sensory to the palmar surfaces of the medial 1.5 digits. (add “of the ulnar nerve” when naming)
Deep Branch: Motor to all intrinsic muscles of the hand except 2LOAF
