Equine Neck Flashcards
What structures are palpable in neck of horse
- Point of shoulder
- Scapular spine
- Scapular cartilage
- Withers
- Trachea
- Manubrium
- Crest of Neck
- Angle of mandible
- Poll
- Thyroid gland
- Cervical vertebrae (wing of atlas palpable)
suprascapular nerve horse
prone to injury because horses lack acromion leaving it more exposed and more likely to be injured
where do you palpate point of shoulder
cr division greater tubercle of the humerus
where do you palpate scapular cartilage
btwn spine of scapula and withers
What are the withers
correspond to spinous processes T2-T8
Where is trachea located/ palpable
ventral in neck
what is manubrium
cr most aspect of sternum
where is crest of the neck located
dorsal to vertebra, contains fat
where is the thyroid gland located
proximal 1/3 of neck cd to larynx and dorsolateral to trachea, moveable, bilobed
AO joint
located between atlas and skull; CSF tap uses AO jt by flexing head toward limb to access it, usually go in C1 or C2
pectoral grooves
lateral and median pectoral grooves
Median pectoral groove boundaries
descending component of superficial pectoral muscles bilaterally
Median pectoral groove clinical significance
Manubrium is palpable at proximal most aspect of groove, can use to find sternum for bone marrow aspiration
Lateral pectoral groove boundaries
medial- deciding component of superficial pectoral muscle
lateral- brachiocephalicus (cleidomastoideus)
What lies in lateral pectoral groove
- Cephalic vein
2. Branch of superficial cervical artery
Clinical application pectoral grooves
avoid vessels in lateral pectoral groove when using pecs for IM shots; hold thumb in median groove and index finger in lateral groove and give shot in middle
Location of dorsal branch accessory nerve
runs between omotransversarius (dorsal border) and trapezius
dorsal branch accessory nerve innervates
provides motor innervation to trapezius and splenius
location ventral branch accessory nerve
runs deep to wing of atlas and converges with ventral branch C1
ventral branch accessory nerve innervates
provides motor innervation to sternocephalicus and brachiocephalicus (cleidomastoideus)
general path of accessory nerve
exists skull via tympanooccupital fissure; dorsal and ventral branch diverge close to C1
draw and label basic spinal nerve
DR -> DRG -> SN -> DB -> medial branch DB or lateral branch DB
VR -> SN -> VB
SN -> CB
medial branch of DB
Dorsal cutaneous branch in cervical region
lateral branch of DB
dorsal cutaneous branch in thoracic and lumbar regions
boundaries of virbog’s triangle
- Tendon of sternocephalicus
- Ramus of mandible
- Linguofacial vein
Boundaries of jugular groove
Dorsal: brachiocephalicus (cleidomastoideus)
ventral: sternocephalicus
Medial: cr 1/3 neck bounded by omohyoideus
Lateral: Cd 2/3 of neck cutaneous coli
Clinical significance omohyoideus and jugular groove
separates ext jug from deeper carotid sheath -> lower chance IV medication going into artery so give IV shots in cr 1/3 neck in horses
clinical significance of cutaneous coli
can make it hard to raise jugular vein if muscle is contracted
Carotid sheath formed by
deep cervical fascia
boundaries of carotid sheath
- Deep to omohyoideus cr 1/3 of neck
- lateral to deep fascia of esophagus
- Bounded ventrally by trachea?
- bounded dorsally by longs Colli and scalenus?
Contents of carotid sheath
- Common carotid artery
- Vagosympathetic trunk
- Tracheal duct
- +/- recurrent laryngeal nerve
- +/- internal jug
Components of nuchal ligament
Funicular and lamellar portion
Lamellar portion nuchal ligament
attached to cervical vertebrea; elastic fibers allow head to lower for grazing and raise with lower energy expendature
Funicular portion of nuchal ligament
double cord of CT running dorsally; starts at external occipital protuberance and runs to withers caudally and continues as supraspinous ligament
Bursae
synovial surface where ligament runs over bone, can become inflamed and infected
nuchal bursae
formed dorsal to C1, C2, and T2/T3 to minimize pressure as funicular portion of nuchal ligament passes over bony prominences
Cr nuchal bursae, Cd nuchal bursae, supraspinous bursae
cr nuchal bursae
between nuchal ligament and C1
cd nuchal bursae
between nuchal ligament and C2
supraspinous bursae
over withers (T2-T3)
Dorsoscapular ligament location
arises from supraspinous ligament over withers and inserts on medial aspect of scapula along with serratus ventralis
dorsoscapular ligament function
shock absorber when hoof hits the ground, limits dorsal shift of scapula
Major lymph nodes found in neck and associated with thorax
Superficial cervical lymph nodes and deep cervical lymph nodes (cranial deep cervical lymph nodes, middle cervical lymph nodes, and caudal cervical lymph nodes)
Superficial cervical lymph nodes location
- cr aspect of scapula along cr edge of subclavius
- deep to omotransversarius and brachiocephalicus
- superficial to omohyoideus
superficial cervical lymph nodes filter lymph from
neck, thorax, shoulder, arm
superficial cervical lymph nodes send efferents to
cd deep cervical LNs
Cd deep cervical LN location
base of thoracic inlet
structures nearby superficial cervical LNs
branch of superficial cervical artery is in close association
components deep cervical LNs
cranial, middle, caudal
Cr deep cervical LN location
between common carotid artery and thyroid gland
cr deep cervical LNs receive lymph from
mandibular and retropharyngeal LNs of head
cr deep cervical LNs send efferents to
middle deep cervical LNs then to cd deep cervical LNs
structures nearby cd deep cervical LNs
superficial cervical LNs and cr mediastinal LNs
course of the esophagus in neck
esophagus dorsal to trachea in cr portion of neck then moves to L of trachea
esophagus enclosed in
envelope of deep fascia
wall of esophagus
2 layers of striated muscle and tough longitudinally folded mucosa, striated muscle ends at base of heart
how can infection in deep cervical fascia affect other areas of body
deep cervical fascia is continuous with end-thoracic fascia so if an infection in deep cervical fascia spreads then I t can be spread to thorax where it is harder to control
Palpable LNs in horses
Mandibular?
superficial neck muscles
splenius, trapezius, omotransversarius, brachiocephalicus, sternocephalicus, serratus ventralis, omohyoideus
deep neck muscles
serratus ventralis, rhomboideus, subclavius, scalenus, omohyoideus, expaxials (longissmus, semispinalis capitus), Longus muscles (longus coli, longus capitus)
Explain branching basic spinal nerve
DR and VR converge forming SN which diverges into DB and VB; DB splits into lateral and medial branches
Cervical region spinal nerve
Dorsal cutaneous branch splits from medial branch; VB -> ventral cutaneous branch
Thoracic region spinal nerve
dorsal cutaneous branch from lateral branch; ventral branch splits into lateral and ventral cutaneous branches
lumbar region spinal nerve
dorsal cutaneous branch from lateral branch; ventral branch splits into lateral and ventral cutaneous branches
General path of spinal nerves C1-C5
In cervical region medial branch of DB gives off dorsal cutaneous branches (sensory to dorsolateral neck); lateral branches of DB = motor muscles of neck and give off some cutaneous branches
brachial plexsus
ventral branches C6-T2
phrenic nerve
ventral branches C5,C6,C7
prescapular branch superficial cervical artery
passes dorsally through superficial cervical LNs
short superficial cervical artery
passes cranially from subclavian as subclavian winds around 1st rib
cephalic vein location
in groove between descending pectoral and brachiocephalicus (aka lateral pectoral groove)
