November 16 Flashcards
Vertebral Artery
Segments
1.Preforaminal (from subclavian artery to transverse foramen of C6)
2. Foraminal (through the transverse foramina of C6 to C2)
3. Extradural (from the transverse foramen of axis to the vertebral canal)
4. Intradural (from the vertebral canal to the inferior border of pons)
Branches
Anterior spinal, posterior spinal, posterior inferior cerebellar, meningeal, medullary, basilar arteries
Clinical relation
Stroke
Vagus nerve
The vagus nerve carries special visceral efferent/branchiomotor fibers from the nucleus ambiguus and general visceral efferent/parasympathetic fibers from the posterior (dorsal) nucleus of vagus nerve. General somatic afferent/sensory fibers are carried to the spinal nucleus of trigeminal nerve, while both general and special visceral afferent fibers arrive at the nucleus of solitary tract.
The vagus nerve emerges from the lateral surface of the medulla as a group of rootlets that merge before exiting the skull via the jugular foramen between the glossopharyngeal (CN IX) and accessory (CN XI) nerves. In this region, the vagus nerve bears the superior (jugular) ganglion that contains the cell bodies of GSA fibers and has connections to the glossopharyngeal nerve, cervical sympathetic trunk and cranial root of accessory nerve (which is nowadays considered as a functional component of the vagus nerve). The superior ganglion gives off a meningeal branch (not shown) as well as an auricular branch, which supplies parts of the auricle and tympanic membrane. Below the superior ganglion is the inferior (nodose) ganglion which contains cell bodies of visceral and special sensory fibers of the vagus nerve and has connections with the hypoglossal nerve (CN XII).
After exiting the jugular foramen, the vagus nerve gives off a pharyngeal branch which supplies motor function to pharyngeal constrictor and palatine muscles, as well as receiving some GVA/sensory fibers from the pharyngeal plexus also. It also communicates with the carotid branch (of CN IX). The final upper cervical branch seen here is the superior laryngeal nerve.
Vagus Nerve
Structure Fiber types: General somatic afferent (GSA), special visceral afferent (SVA), general visceral afferent (GVA), general somatic efferent (GSE), general visceral efferent (GVE)
Origin: Medulla oblongata
Motor nuclei: Nucleus ambiguus (SVE), dorsal vagal nucleus (GVE)
Sensory nuclei: Spinal nucleus of trigeminal nerve (GSA), nucleus of solitary tract (GVA/SVA)
Associated ganglia: Superior and inferior ganglia of CN X
Branches Jugular fossa: Meningeal, auricular branches
Neck: Pharyngeal, superior laryngeal, recurrent laryngeal nerve (right only); superior/inferior cervical cardiac branches
Thorax: Recurrent laryngeal nerve (left only), thoracic cardiac branches, bronchial branches, esophageal branches
Abdomen: Posterior vagal trunk (posterior gastric, celiac, renal branches), anterior vagal trunk (anterior gastric branches, hepatic, pyloric branches), intestinal branches (up to left colic flexure)
Function General somatic afferent (GSA): Larynx, laryngopharynx, part of the external acoustic meatus, and dura mater of
posterior cranial fossa
General visceral afferent (GVA): Aortic body chemoreceptors/aortic arch baroreceptors, esophagus, bronchi, lungs, heart, and abdominal viscera of foregut and midgut
Special visceral afferent (SVA): Taste from root of tongue and epiglottis
General somatic efferent (GSE): Palatoglossus muscle, muscles of soft palate (except tensor veli palatini), muscles of pharynx (except stylopharyngeus) and muscles of larynx
General visceral efferent (GVE): Parasympathetic/secretomotor fibres to smooth muscle and glands of the pharynx and larynx, parasympathetic innervation of thoracic viscera, and abdominal viscera of the foregut and midgut
Uterus
The supports of the uterus include the central perineal tendon (the most important). The lateral cervical, round and uterosacral ligaments are condensations of the endopelvic fascia and provide additional structural support.
Suprascapular Nerve
The suprascapular nerve arises from the upper trunk of the brachial plexus.It innervates both supraspinatus and infraspinatus and initiates abduction of the shoulder. If damaged, patients may be able to abduct the shoulder by leaning over the affected side and deltoid can then continue to abduct the shoulder.
