nerves and blood vessels of the front leg Flashcards
spinal nerves are nerves that come out from
between the vertebrae form the spinal cord, one pair per vertebra; dorsal or ventral root
dorsal and ventral branch of spinal nerves
dorsal branch comes up to muscles and skin above vertebra
ventral branch everywhere else including limbs
afferent nerves; direction of info? which root? where are cell bodie?
bring info IN to CNS; come in via dorsal root, cell bodies in ganglion
efferent nerves; direction of info? which root? where are cell bodies?
taking signals OUT of CNS, via ventral root, cell bodies in spinal cord
where do spinal nerves exit the vertebral column
between adjacent vertebra immediately above (dorsal) to the intervertebral disk
how do you name the spinal nerves
C1 to C7: Exit cranially to their corresponding vertebra.
C8: Exits caudally to the seventh cervical vertebra (C7) and cranially to the first thoracic vertebra (T1).
Thoracic, lumbar, sacral, and coccygeal nerves: Exit caudally to their corresponding vertebra.
spinal nerves to each limb forms a
plexus
contribution from several spinal nerves
what do plexuses allow for
regrouping and reassociation of nerve fibers (motor and sensory)
each main nerve contains fibers from
2-3 spinal nerves
name 3 reasons its important to know nerves
- for diagnosis
- to avoid damage during surgery
- for prognosis
the suprasacular nerve innervates which 2 muscles
supraspinatus and infraspinatus
musculocutaneous nerve innervates which 2 muscles
flexors of the elbow
biceps brachii and brachialis
radial nerve innervates
extensors of elbow, carpus and digits
triceps, extensor carpi radialis, ulnaris lateralis, CDE, LDE, supinator, abdominal pollicis longus (dorsal mm muscles)
Median nerve innervates
Flexor muscles of digits and carpus
flexor carpi radialis, pronator teres, SDF and part of the DDF
Ulnar nerve innervates
flexor carpi ulnaris and part of DDF (the ulna head)
musculocutaneous, ulnar and median nerve innervates _____ muscle masses while
radial nerve innervates _____ muscle masses
ventral
dorsal
General principles limb nerves
- They arise from a plexus with contributions from several spinal nerves
- Most have mix of motor and sensory fibers
- Sensory part of the nerve often extend distal to motor part
- Generally on medial side or deep to muscles where they are protected
- Follow the dorsal and ventral muscle masses
reptile twist again
For upper limb:
From reptile to dog, dorsal becomes caudal, ventral becomes cranial **
For your lower forelimb (antebrachii) : just remember theres a double twist for the lower forelimb
From reptile to dog the dorsal becomes cranial and ventral becomes caudal
arteries bring blood
veins bring blood
away from heart
to the heart
main stem of artery in the front limb
axillary
describe axillary artery as it goes down the limb
Main stem is axillary artery (comes out of thoracic wall) changes at the shoulder to brachial artery and then at elbow changes into median artery continues all the way down to the foot (so one artery but have 3 names as it goes down the limb)
axillary artery arises from
subclavian artery in thorax
main branches of axillary artery
subscapular artery and thoracodorsal artery
brachial artery passes medially down the humerus between
the biceps and medial head of triceps
(palpable here)
brachial artery is _____ at the elbow where it becomes median artery
cranio-medial
median artery continues medially and supplies the
paw
(both palmar and digital arteries)
major branch of median artery is
radial artery
main veins in front leg
- also have axillary, brachial and median parts of vein
- cephalic vein
cephalic vein has ___ routes for drainage back to heart
3
the cephalic vein joins the median vein via the
median cubital vein
General principles of blood vessels to limbs
- Major vessels on medial side of limb for protection
- One major artery to feed limb, but usually extra venous drainage
- Know the general pattern and where they are superficial
