exam 2: nervous system brachial plexus Flashcards
T/F Spinal roots are unidirectional
true
are dorsal roots or ventral roots comprised of afferent fibers
– sensory and proprioceptive fibers?
dorsal root
are dorsal roots or ventral roots comprised of efferent fibers
– motor neurons (to muscles and glands)
ventral root
T/F Spinal nerves are bidirectional
true
Carries nerve fibers that innervate structures dorsal to the transverse processes
* Afferent and efferent fibers
dorsal or ventral branch
dorsal branch (smaller)
Carries nerve fibers that innervate structures ventral to the transverse processes
* Afferent and efferent fibers
dorsal or ventral branch
ventral branch (larger)
Label the layers of a spinal nerve
- epineurim
2.perineurium
- endoneurium
Brachial Plexus
what is it
what is it formed by
network of nerves to thoracic limb
formed by ventral branches of spinal nerves (+/- C5) C6, C7, C8, T1, T2
_____________branches communicate and give rise to nerves that form the
brachial plexus
ventral branches
3 main functions of brachial plexus
Motor to skeletal muscles
Cutaneous sensory from skin
Proprioception from thoracic limb
Brachial Plexuses are located in the ____________ regions, close related with ________ vessels
axillary
Brachial Plexuses is classified as what kind of joint
synsarcosis (“joint of muscles)
what is this showing
avulsion (seperation) of brachial plexus
this nerve is NOT a nerve described as part of the brachial plexus, doesn’t innervate any structure in the thoracic limb but, the origin is very close to the brachial plexus.
Phrenic nerve
origin of phrenic nerve
C5-C6-C7
Is the phrenic nerve motor or sensory
Motor nerve of diaphragm
what nerve is being pointed to
phrenic nerve
Autonomous Zone (AZ) is where there is only __ nerve
one
what does green represent? orange?
green= cutaneous area of axillary nerve
orange= cutaneous area of radial nerve
what is being pointed to by the black arrow
overlap zone
what is being pointed to by the black arrows
autonomous zones
T/F: Nerves must have a cutaneous zone in order to have an overlap zone or autonomous zone
true
Extrinsic muscles of thoracic limb:
cleidobrachialis m is innervated by what nerve
Brachiocephalic n. (motor and sensory)
Extrinsic muscles of thoracic limb:
Superficial pectoral m. is innervated by what nerve
Cranial pectoral nn (motor)
Extrinsic muscles of thoracic limb:
Deep pectoral m. is innervated by what nerve
Caudal pectoral nn( motor)
Extrinsic muscles of thoracic limb:
Latissimus dorsi m. is innervated by what nerve
- Thoracodorsal n (motor)
Extrinsic muscles of thoracic limb:
Serratus ventralis m is innervated by what nerve
Long thoracic n (motor)
Cutaneous trunci m. (not
an extrinsic muscle) is innervated by what nerve
Lateral thoracic n (motor)
what nerve is the yellow arrow pointing to
Brachiocephalic n. (very cranial)
what nerve is being pointed to by the yellow arrow
Long thoracic n
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Suprascapular nerve
is it motor or sensory?
(C6, C7)
* Motor to:
– Supraspinatus m.
– Infraspinatus m.
- No sensory innervation!!!!
what nerve is this
Suprascapular n.
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Subscapular nerve
is it motor or sensory?
(C6, C7)
Motor to:
– Subscapularis m.
- No sensory innervation!!!
what nerve is being pointed to
Subscapular nerve
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Musculocutaneous nerve (C6,C7,C8)
is it motor or sensory?
- Motor to:
– Biceps brachii m.
– Brachialis m.
– Coracobrachialis m. - Sensory to:
– Medial aspect of antebrachium
If there is damage to the suprascapular nerve what would the result be
Can’t laterally stabilize humeral joint extend humeral joint
If there is damage to the subscapular nerve what would be the result
Cannot medially stabilize humeral joint
if there is damage to the Musculocutaneous nerve what would the result be
no flexion of cubital joint
may have paralysis
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Axillary nerve (C7,C8)
is it motor or sensory?
- Motor to:
– Teres major m.
– Teres minor m.
– Deltoideus m.
– Caudal part of Subscapularis m. - Sensory to:
– Craniolateral shoulder area
– Cranial aspect of antebrachium
if there is damage to the axillary nerve what would be the result
probably cant flex humeral joint
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Radial nerve (C7,C8, T1, T2)
what all muscles is it motor to?
- Motor to:
– Triceps brachii m.
– Tensor fasciae antebrachii m.
– Anconeus m.
– Extensor carpi radialis m.
– Common digital extensor m.
– Lateral digital extensor m.
– Extensor carpi ulnaris m.
– Supinator m.
– Abductor pollicis longus m (not important)
– Brachioradialis m. (not important)
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Radial nerve (C7,C8, T1, T2)
sensory to?
Cranial and lateral aspect of
antebrachium
Medial and dorsal aspect of
manus
if there is damage to the radial nerve what happens
NO RADIAL NERVE, NO THORACIC LIMB
no extension of cubital joint or carpal joint
no flexion humeral joint (long head of tricep)
cannot support body
what is being pointed to in blue?
red?
blue- superficial branch of radial nerve
red- deep branch of radial nerve
what is the blue arrow pointing to?
grey arrow?
blue= superficial branch of radial nerve
grey= cephalic vein
label 1 and 2
- Antebrachial cutaneous nn. of radial nerve
- Dorsal common digital nn. of radial nerve
Radial nerve innervates triceps brachii m., tensor fasciae antebrachii m. and anconeus m. then divides into
Deep branch (motor)
Superficial branch
Deep branch (motor) of radial nerve Innervates
extensors mm. and supinator m. of the antebrachium
Superficial branch of radial nerve is sensory to:
Cranial and lateral aspect of
antebrachium
Medial and dorsal aspect of
manus
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Median nerve (C8,T1,T2)
motor or sensory
- Motor to:
– Pronator teres m.
– Flexor carpi radialis m.
– Superficial digital flexor m.
– Deep digital flexor m.
– Pronator quadratus m. - Sensory to:
– Palmar aspect of manus
Nerves of the brachial plexus
innervating intrinsic thoracic limb muscles:
Ulnar nerve (C8,T1,T2)
motor or sensory
Motor to:
– Flexor carpi ulnaris m.
– Deep digital flexor m.
– Interossei mm.
Sensory to:
-Caudal aspect of antebrachium
(Caudal antebrachial cutaneous n.)
-Palmar aspect of manus
-Lateral side of digit 5th
what nerve is 1? 2?
- Median n.
- Ulnar n.
what nerve is this
Ulnar n.
what is being pointed to
Ulnar n. Cutaneous branch to
digit v
if there is damage to Median nerve what would probably happen
may not be able to:
-flex carpal jt, metacarpophalangeal jt, proximal interphalangeal jt, digital joint
- pronate manus
if there is damage to the ulnar nerve what may the animal not be able to do
-flex antebrachial joint
-flex carpal or digital joint
-support and flex
metacarpophalangeal joint
