Lesion Local 4 Flashcards
If reflexes are normal to increased in thoracic limbs in animal w tetraparesis
Then localization is a C1-5 myelopathy
If reflexes are decreased to absent in thoracic limbs in animal w tetraparesis
Then localization is a C6-7 myelopathy or lower motor neuron
Patellar reflex
Hit patellar tendon = stretches pat tendon (spinal fibers)
Signal travels up dorsal root through spinal cord then down ventral root to quadriceps muscle = extension
Patellar reflex mechanism
Patellar tendon
Golgi tendon organ
Afferent portion of the nerve
Dorsal nerve root
L4-6 spinal cord segments
Ventral nerve root
Efferent portion of the nerve
NMJ
Quadriceps muscle
Brachial plexus region
C6-T2 region
Suprascapularis nerve supply
C6 & 7
Subscapularis nerve supply
C6 &7
Axillary nerve supply
C6, 7, 8
Radial nerve supply
C7, 8, T1, 2
Median nerve supply
C8, T1, 2
Ulnar nerve supply
C8, T1, 2
Shoulder nerve supply and origin
Suprascapularis, subscapularis, musc, axillary
C6, 7, 8
Elbow nerve supply
Musc, axillary, radial nerves
C6, 7, 8, T1, T2
Carpus nerve supply
Radial, median and ulnar
C7, 8, T1, T2
Withdrawal reflex
Stimulus to toe, travels radial nerve to caudal intumescence
Dorsal root ganglion, spinal cord, LMN = flexion of limb
Ideally seeking flexion of joints
Lack of flexion = abnormal function of nerve
Radial nerve
Featured on dorsal aspect of limb
Ulnar nerve
Featured on lateral and ventral sides of limb
Musculocutanous nerve
Featured on the medial side of limb
Withdrawal reflex efferent - ulnar and median
Withdrawal on carpus indicates proper function of ulnar and Median nerves
Withdrawal reflex efferent on musculocutanous nerve
Withdrawal of biceps and brachialis muscles indicates proper function of musculocutanous nerve
Withdrawal reflex efferent of Supraspinatous & axillary nerves
Withdrawal of the shoulder, deltoid & suprascapular muscle indicates proper function of the suprascapular & axillary nerve
Polysynaptic reflex
Reflex that has multiple synapse at the spinal cord or brain
Shoulder reflex
Cranial intumescence
Elbow reflex
Mid intumescence
Carpal reflex
Caudal intumescence
Vertebral origin of femoral nerve
L4, 5, 6
Vertebral origin of obturator nerve
L4, 5, 6,
Vertebral origin of cranial gluteal nerve
L6, 7, S1
Vertebral origin of caudal gluteal nerve
L6, 7, S1, S2
Vertebral origin of sciatic nerve
L6, 7, s1, s2,
Vertebral origin of pudend. Nerve
S1, 2, 3
Withdrawal reflex - afferent
Distally
Tibial, Fibular
Withdrawal reflex - afferent
Laterally
Sciatic
Withdrawal reflex - afferent
Medially
Saphenous / femoral
Caudal intumescence lesion - pelvic limb
Good hip & stifle flexion
No stifle flexion
Reflexes normal to increased in pelvic limbs
In Animal with paraparesis, lesion is localized to T3-L3 myelopathy
if reflexes are decreased to absent in pelvic limb i
In animal with paraparesis, localization is L4-S3 myelopathy or LMN
Use for sciatic nerve reflex
Common in animals in lateral recumbency
Find sciatic notch. Proper function should flex the stifle
(L6-S1)
Use for gastroc reflex
Used after cranial tibial
Strike muscle belly, proper function should result in extension of the hock, contraction of thigh muscles may occur. Innervated by tibial branch of sciatic (L7-S1)
Use for Cranial tibial reflex
Proper functional response is flexion of the hock
Innervated by Fibular branch of sciatic nerve (L6-7)
Grading scale for reflexes
0 - absent
1 - delayed
2 - normal
3 - increased
4 - clonus
*difference between 3 & 4 = presence of UMN disease
Crossed extensor
Extension of opposite limb from stimulated during flexor reflex tests
Indicates UMN disease, likely chronic
Babinski reflex
Stroking limbs on caudolateral surface of hock to digits, animal should elicit no response. Any response like extension and fanning of digits indicates UMN disease
Perineal reflex
Winking of booty hole, testing pudendal nerve (S1-3)
Cutaneous trunci
Start caudally
Afferent T3-L5
Efferent is lateral thoracic nerve
- C8-T1 spinal cord segments
- cutaneous trunci muscle
Useful for focusing lesions in T3-L5
Hyperpathia
Something that could be painful with enough force, but applied force should not be painful*
Hyperesthesia
Something that shouldn’t be painful but is
Nociception
Deep pain
More resistant pathways to damage than other pathways. Withdrawal on deep pain, indicates only an intact reflex arc (peripheral nerve & spinal segments)
Deep pain is important for assessing prognosis & surgery
Bladder control
L1-4, UMN bladder = lesion= increased tone to bladder wall/detrusser muscle & pudendal nerve
s1-3, LMN bladder - lesion = incontience, no tone to detrusser muscle
Pelvic nerve - parasympathetic, releasing bladder
Hypogastric nerve - sympathetic, filling bladder
Detrusor muscle tone
UMN - increased
LMN - decreased
Urethane sphincter tone
UMN - increased
LMN - decreased
Bladder expression
UMN - difficult, urinary retention
LMN - easy, urinary incontinence
