lecture 6- equine limb vessels, nerves, and distal limb blocks

pimentel

where is the brachial plexus found

C6-T2

what is this

suprascapular

what is sweeny shoulder

damage to suprascapular nerve not uncommon in horses

results in atrophy of supra and infraspinatus, shoulder instablity, and shoulder “slip”

what is this

subscapular n.

what is this

axillary nerve

what is this

musculocutaneous n.

what is the main nerve in this image that we are seeing going down the limb

median n.

what is this

ulnar n

where is radial autonomous zone

lateral portion of brachium

where is ulnar innervation

ventral region of antebrachium AND brachium

where is musculocutaneous innervation

medial/dorsal region of brachium

whta is the cutaneous innervation of the craniomedial antebrachium

explain the breakdown of the cutaneous innervation for the fore digit of the caudal antebrachium and medial antebrachium

what are the parts of the median nerve

communicating branch

medial palmar

medial digital palmar

• dorsal branch

what are the branches of ulnar nerve

dorsal branch

what are the branches of the lateral palmar nerve

lateral digital palmar

what are the branches off the lateral digital palmar n

dorsal branch

medial palmar metacarpal

lateral palmar metatarsal

explain the blood supply of the thoracic limb

where is the LS plexus found

L4-S2

what is the dark blue arrow

femoral n.

what is the light blue arrow

saphenous

what is this

obturator n.

what is the union between the median and musculocutaneous n.

ansa axillaris

what is the top dark blue arrow

sciatic n.

what is the middle light blue arrow

tibial

what is the bottom light blue arrow

common fibularis

where is tibial innervation

caudal portion of leg

where is saphenous innervation

medial thigh

where is peroneal innervation

lateral portion of shin

what is the cutaneous innervation of the hind digit of the craniomedial tibia

saphenous

what are the cutaneous innervation of the hind digit at the cranial tibia level and what are the branches

what nerve innervates the most distal part of the thoracic limb

median

what are the cutaneous innervations of the hind digit at the caudal tibia

explain vasculature of the pelvic limb

w

regional anesthesia useful, fast, affordable, efficient

distal limb blocks

what are the 4 types of distal limb blocks

1. Palmar/plantar digital

2. Abaxial sesamoid

3. Low 4 points

4. High 4 points

technique for palmar digital nerve block

• Insert the needle subcutaneously over the neurovascular bundle.

• Close to the proximal border of the ungular cartilage.

nerves blocked by palmar digital nerve block

palmar digital nerves

• VAN

what will palmar digital nerve block affect

• Facies solaris (Sole)

• Navicular Apparatus

• Distal interphalangeal joint (Coffin)

• Distal flexor tendon sheath

• Distal sesamoidean ligaments

• Loss of skin sensation at the heel

technique for abaxial sesamoid nerve block

• Insert the needle at the abaxial surface of the sesamoid at the caudal edge of the neurovascular bundle.

• Point needle distally

nerves for abaxial sesamoid nerve block

palmar digital nerves

main areas affected by abaxial sesamoid nerve block

• Distal phalanx

• Middle phalanx

• Proximal and distal

interphalangeal joints (Coffin and pastern)

• Distal SDF and DDF

• Distal sesamoidean ligaments

• Digital annular ligaments

• +/- Metacarpo/tarsophalangeal

joint (Fetlock)

technique for low 4 point (low palmar) block

• Insert the needle distal to the head (button) of the II and IV metacarpal/tarsal (splint) bones.

• Drive the needle subcutaneously between the interosseous ligament and the DDF tendon

nerves affected by low 4 point block

• Palmar metacarpal/metatarsal nerves (medial

to metacarpal/metatarsal bones)

• Palmar nerves (between interosseous and

DDFT)

pelvic limb performing a low 4 point block

• Performed the same as the thoracic limb.

• Will not reliably anesthetize the skin dorsally

• Important for suturing a laceration

• Less important for a lameness work up

• Can do a dorsal ring block to anesthetize the skin

high 4 point block thoracic technique

• Inject subcutaneously on dorsal surface of the DDFT through the fascia (retinaculum flexorum) just distal to the carpo-metacarpal joint

• Flex the limb and insert the needle along the metacarpal bones II and IV pointing at palmar MC3

high 4 point block thoracic nerves

medial and lateral palmar nerves

medial and lateral palmar metacarpal nerves

high 4 (6) point block of hind limb technique

• 1.5in needle inserted 1cm distal to tarso-metatarsal joint on either side and

hit the back of Metetarsal bone III

• 25g 5/8in needle – deposit 3-5ml through the fascia over the DDFT on

medial and lateral side

• 2cm distal to the TMT at 10 and 2 o’clock positions on the dorsal aspect od

the metatarsal bone III.

nerves of high 4 point block of hind limb

• Medial and lateral plantar nerves

• Medial and lateral plantar metatarsal nerves

• Dorsal metatarsal nerves