Behind the SCM

Question 1

Contents of the carotid sheath

Answer 1

common and internal carotid aa. 
internal jugular v. 
vagus n. 
ansa cervicalis 
deep cervical lymph nodes 

artery is medial and vein is lateral and posterior
vagus is posterior b/w vessels
ansa is lateral to the aa. and corrses v.

Question 2

Common carotid aa

Answer 2

left side is longer than the right
splits at CV3
DOES NOT BRANCH USUALLY

Question 3

carotid sinus

Answer 3

lcoated at the dilated, distal common carotid and proximal internal carotid pressure (baro) receptor
inc pressure=dec HR

Question 4

carotid body

Answer 4

located at the carotid bifurcation, chemoreceptor

dec O2—> inc RR (via vagus)

Question 5

Branches of the internal carotid a.

Answer 5

DOES NOT BRANCH PRIOR TO ENTERING THE SKULL

Question 6

Course of the external carotid a.

Answer 6

branches in the carotid triangle at CV3 at near the superior horn of the thyroid cartilage
1st four branches: superior thyroid, ascending pharyngeal, ligual, facial

after it passes the posterior digastric and stylohyoid it gives off occipital and posterior auricular

terminates near the neck of the mandible into the maxillary and superficial temporal aa.

Question 7

Superior thyroid gland

Answer 7

first branch of the external carotid a.

gives off the superior pharyngeal a., anterior branch and posterior branch

Question 8

superior deep cervical lymph nodes

Answer 8

located int eh carotid triangle superior to the superior bell of the omohyoid
composed of retropharyngeal , jugulodigastric nodes (and others)-where tonsilitis can dissect

Question 9

inferior deep cervical lymph nodes

Answer 9

located inferior to the superior belly of the omohyoid
last common node for all head lymph nodes (superificial cervical nodes, superior deep nodes, accessory chain, JUXTAVISCERAL Nodes0

drain into the jugular lymph trunks (which on the L drain into the thoracic duct and on the R drain into the R lymphatic duct

Question 10

course of the hypoglossal n. XII

Answer 10

runs thru the hypoglossal canal medial to the internal jugular v and internal carotid a., but still within the sheath

communicates with CN X and superior cervical ganglia and ventral rai of C1 and 2

enters the submandibular triangle, passes b/w the mylohyoid and hyloglossus to entern teh tongue

Question 11

functions of the cervical plexus

Answer 11

composed of ventral rami of C1-C4

motor to deep cervical vertebral muscles, infrahyoids, and diaphragm
sensory to the lateral head, neck, superior shoulder, upper thorax

distribute post SNS from cervical ganglia

Question 12

sensory fibers C1 and C2

Answer 12

can join up with the hypoglossal n. or the vagus n. and travel retrograde in order to innervate the dura mater of the cranial fossa

Question 13

proprioceptive fibers of C2-C4

Answer 13

travel with the spinal accessory n to pass thru the SCM (C2 and C3) and the trapezius (C3 and C4)

Question 14

cord levels of SNS pre cell bodies

Answer 14

T1-T4…..travel thru the ventral root, into the chain, into the cervical sympathetic ganglia (superior, middle, vertebral, inferior)

Question 15

superior cervical ganglia

Answer 15

fused cervical ganglia of C1-C4
located on the anterior surface of longus capitis

PROVIDES ALL post-ganglionic SNS fibers to the the head (there are NO PRE-ganglionic fibers in the head)

gives rise to the internal carotid n., Ext carotid n. and superior cervical cardiac n.

Question 16

middle cervical ganglia

Answer 16

fused C5 and C6
near the inferior thyroid a.

provides grey rami to C5 and C6
middle cardiac n. (Largest)
Ansa subclavia-around the subclavian a. around the subclavian, medial the TC trunk and vagus where it rejoins the inferior cervical ganglia

Question 17

vertebral ganglion

Answer 17

near the base of the vertebral a.

gives rise to vertebral plexus which rides on the vertebral a.

MAY contribute to the ansa subclavia

Question 18

inferior cervical ganglia

Answer 18

fused ganglia of C7 and C8
may be fused with the thoracic ganglia

provides grey rami to spinal nn. C7-T1 and to the vertebral plexus
inferior cardiac n. to the cardiac plexus
vasomotor fibers to the subclavian and inferior thyroid via thyrocervical trunk

fibers to run with recurrent laryngeal