Canine Brachial Plexus And Thoracic Limb Nerves Flashcards
Are the ventral branches of spinal nerves bidirectional or unidirectional?
Bidirectional
The ventral branches of spinal nerves give rise to what structure?
Brachial plexus
The brachial plexus includes which vertebrae?
C6 - T2
The brachial plexus is the nerve supply to what?
Thoracic limb
The phrenic nerve is associated with the brachial plexus because it is associated with which vertebrae?
C5-C6-C7
The phrenic nerve is the motor nerve of what structure and what does it control?
Diaphragm, breathing (inspiration)
The thoracic limb has cutaneous innervation via what nerves of the brachial plexus?
Axillary nerve and radial nerve
The area where nerves overlap is called what?
Overlap Zone (OZ)
What is the area where nerves do not overlap called?
Autonomous zone (AZ)
In what zone can we test if cutaneous innervation is functional?
Autonomous zone
What are the extrinsic nerves of the brachial plexus?
Brachiocephalic nerve, cranial pectoral nerve, caudal pectoral nerve, thoracodorsal nerve, long thoracic nerve, lateral thoracic nerve
What are the intrinsic nerves of the brachial plexus?
Suprascapular nerve, subscapular nerve, musculocutaneous nerve, axillary nerve, radial nerve, median nerve, ulnar nerve
True or false: Motor nerves always have proprioception.
True
General somatic efferent refers to motor or sensory nerves?
Motor
General somatic afferent refers to motor or sensory nerves?
Sensory
The Brachiocephalic nerve provides sensory and motor function to what structure?
Cleidobrachialis m
The cranial pectoral nerve supplies motor function to what structure?
Superficial pectoral m
The caudal pectoral nerve supplies motor function to what structure?
Deep pectoral m
The thoracodorsal nerve supplies motor function to what structure?
Latissimus dorsi m
The long thoracic nerve provides motor function to what structure?
Serratus ventralis m
The lateral thoracic nerve provides motor function to what structure?
Cutaneous trunci m
Note that the nerve is considered extrinsic but the muscle it innervates is not
The suprascapular nerve supplies motor function to what structure?
Supraspinatus and infraspinatus muscles
The subscapular nerve provides motor function to what structure?
Subscapularis muscle
The musculocutaneous nerve provides sensory and motor function to what structures?
Biceps brachii m, brachialis m, coracobrachialis m
Sensory to: medial aspect of antebrachium, palmar aspect of manus
The axillary nerve provides sensory and motor function to what structures?
Teres major m, teres minor m, deltoideus m, caudal part of subscapularis m
Sensory to: craniolateral shoulder area, cranial aspect of antebrachium palmar
The radial nerve provides sensory and motor function to what structures?
Triceps brachii m, tensor fasciae antebrachii m, anconeus m, brachioradialis m, extensor and supinator mm
Sensory to (superficial branch): cranial and lateral aspect of antebrachium, medial and dorsal aspect of manus
The radial nerve runs closely with what vessel?
Cephalic vein
What branch provides sensory function from the radial nerve?
Superficial branch
What branch provides motor function from the radial nerve?
Deep branch
The median nerve provides sensory and motor function to what structures?
Pronator teres m, flexor carpi radialis m, superficial digital flexor m, deep digital flexor m, pronator quadratus m
Sensory to: palmar aspect of the manus
The ulnar nerve provides sensory and motor function to what structures?
Flexor carpi ulnaris m, deep digital flexor m, interossei mm
Sensory to: caudal aspect of the antebrachium, palmar aspect of manus, lateral side of digit 5
The segment of vertebrae that gives rise to the nerves supplying the thoracic limb is called?
Cervical intumescence
Spinal roots are unidirectional or bidirectional?
Unidirectional
The dorsal spinal roots are comprised of what type of fibers?
Afferent (sensory and proprioceptive)
The ventral spinal roots are comprised of what fibers?
Efferent (motor neurons to muscles and glands)
The dorsal branch of spinal nerves carry nerve fibers that innervate structures _______ to the transverse processes.
Dorsal
The ventral branch of spinal nerves carry nerve fibers that innervate structures _______ to the transverse processes.
Ventral
Nerves must have what in order to have an overlap zone or autonomous zone?
Cutaneous area (CA)
What nerve has a communicating branch with the median nerve proximal and medial to the cubital joint?
Musculocutaneous nerve
The superficial branch of the radial nerve is divided into what?
Two antebrachiocutaneous nerves
The antebrachiocutaneous nerves of the superficial branch of the radial nerve are responsible for what?
The autonomous zone of the radial nerve is divided
The antebrachiocutaneous nerves of the superficial branch of the radial nerve run parallel to what vessel?
Cephalic vein
The ulnar nerve has a superficial branch named what?
Caudal antebrachial cutaneous nerve
What are the autonomous zones of the ulnar nerve?
Caudal area of the antebrachium and Abaxial areas of the fifth digit
The suprascapular nerve can be found where?
Cranial to the scapular notch
The subscapular nerve can be found where?
Medial view when you get into the subscapular m
The musculocutaneous nerve can be found where?
Between the biceps brachii and the brachial artery in a medial view
The axillary nerve can be found where?
Caudal to the neck of the scapula
The median nerve can be found where?
Originates from common trunk with ulnar nerve in the proximal and medial region of the brachium. It runs caudal to the brachial artery.
The ulnar nerve can be found where?
Originates in common trunk with median nerve. Runs in the groove formed by the medial epicondyle of humerus and the olecranon
The radial nerve can be found where?
It first innervates triceps brachii muscle heads in medial view then deep to the lateral head of the triceps in lateral view
The deep branch of the radial nerve can be found where?
Deep to the extensor carporadialis m. You can reflect this muscle to see the rest of the branch
What would be the motor/sensory deficiency in a radial nerve injury that is at the level of the shoulder joint/brachial plexus?
Lose everything radial nerve related.
Motor to triceps brachii, tensor fascia antebrachii, anconeus, brachioradialis, extensor carpi radialis, common digital extensor, lateral digital extensor, extensor carpi ulnaris, supinator, abductor policis longus
Sensory to cranial and lateral aspect of antebrachium, medial and dorsal aspect of manus
Would cause “wrist drop” due to loss of motor function to extensor muscles of the antebrachium in thoracic limb
What would be the motor/sensory deficiency in a radial nerve injury that is at the level of the cubital joint?
Lose everything at and below cubital joint
Motor to brachioradialis, extensor carpi radialis, common digital extensor, lateral digital extensor, extensor carpi ulnaris, supinator, and abductor policis longus
Sensory to cranial and lateral aspect of antebrachium, medial and dorsal aspect of manus
May cause dropped cubital joint and knuckling of digits due to loss of motor function to carpus and digits
Sensory nerves also have postganglionic sympathetic general visceral efferent fibers. These sympathetic motor fibers are motor for what structures?
Smooth muscles in vessels, piloerector muscle, and glands located in the skin
Motor nerves also have general somatic afferent proprioceptive fibers. These fibers are responsible for what?
Bringing sensory information from stretch receptors located in joints, capsules, ligaments, tendons or skeletal muscles to central nerve system
