Head/Neck Flashcards
Neck Constrictors
Attach to skull base, hyoid bone, thyroid, & cricoid cartilages
Form posterior pharynx wall
Move food bolus down to the esophagus
Superior, middle, & inferior constrictors
Posterior Neck Structures
Dorsal
Vertebrae, epaxial muscles, & prevertebral muscles
Hyoid
Mobile bone
Does not articulate w/ other bones
Suspended in the neck at C3 via muscles & ligaments
Attachment site for several neck muscles
Strap Muscles
Superficial (ventral)
Attach to hyoid bone
Sternohyoid
Sternum → thyroid cartilages
Sternum → hyoid body
Thyrohyoid
Thyroid cartilage → hyoid body & greater horn
Mylohyoid
Mandible inner surface → hyoid body
Scalene
Key neck landmark surrounding vertebrae Brachial plexus emerges b/w anterior & middle scalene Anterior Middle Posterior
Carotid Sheath
Contains common carotid, Vagus nerve X, & internal jugular vein
Sternocleidomastoid
Common origin from mastoid process → sternal & clavicular head
Cervical plexus emerges posterior to sternocleidomastoid
Trapezius
Arises from scapula
Upper (cranial) & lower (caudal) fibers
Upper fibers attach to occiput at skull base
Anterior Triangle
Sternocleidomastoid = key
L & R triangles meet at midline
Continues superiorly to lower jaw border & inferiorly to sternum manubrium
Carotid triangle
Posterior Triangle
Sternocleidomastoid = key
Trapezius posterior border
Clavicle inferior border
Larynx
C3-6
Mobile ↑↓ swallowing & speech
Cervical Plexus
Sensory head & neck
Thyrohyoid Membrane
Connects thyroid cartilage & hyoid bone
Thyroid Cartilage
Shield-shaped lamina
Superior & inferior cornu
Inferior cornu articulate w/ cricoid
Cricoid Cartilage
Ring-shaped cartilage
Only complete ring
Located b/w trachea & thyroid
Arytenoids articulation
Arytenoids
Triangle pyramid w/ vocal & muscular process
Vocal process attaches vocal ligaments
Muscular process attaches muscles that move vocal cords
Arytenoid muscles draw the arytenoids together
Vocal Cords
Cone-shaped ligament free edge
Muscles change rima glottidis shape & tension
Cricothyroid
Tensor
Innerved by external laryngeal nerve
Rotates thyroid cartilage
Pulls thyroid down to stretch & tighten vocal cords
Posterior Cricoarytenoid
ABDuctor
Rotate vocal process laterally (outward)
Opens rima
Lateral Cricoarytenoid
ADDuctors
Rotates vocal process medially
Closes rima
Vocalis
Relaxer
Runs on the ligaments
Glossopharyngeal
Cranial nerve IX
Motor & sensory to pharynx
Taste posterior 1/3 tongue
Exits posterior cranial fossa via jugular foramen
Swallowing
26 muscles
5 cranial nerves controlling muscle movements & sensory input (V, VII, IX, X, XII)
Failure → dysphagia
Extrinsic Tongue Muscles
Move the tongue as whole
Innervated via hypoglossal nerve
Intrinsic muscles shaped the tongue
Palate Muscles
Palate actively raised & lowered during swallowing
Raisers & tensors- levator veli palatini
Depressors - palatopharyngeus
Voluntary Swallowing
Styloglossus & hyoglossus contract pulling tongue back & up
Intrinsic tongue muscles arch tongue upward & backward
Pushes bolus up against hard palate
Palatoglossus contraction squeezes food out oral cavity into oropharynx
Soft palate rises w/ palatini muscle to close off opening b/w nasopharynx & oropharynx
Larynx elevates to meet the epiglottis (stylopharyngeus, stylohyoid, thyrohyoid, & palatopharyngeus muscles) & epiglottis actively pulled down
Swallowing Steps
- Seal nasopharynx - lift soft palate
- Propel bolus - raise hypoid bone & larynx w/ strap muscles
- Seal pharyngeal inlet - stop food from moving back into oropharynx by tightening external tongue muscles & upper constrictors
- Clear bolus - restore hyoid & larynx to original position w/ strap muscles
Contract middle & inferior constrictors
Vagus
Cranial nerve X
Motor & sensory to pharynx & larynx, autonomic PSNS to thorax & abdomen, & sensory taste
Exits via jugular foramen
Nerve damage → relaxed vocal cords
Stridor & hoarse voice
Superior Laryngeal
INTERNAL
Pierces through thyrohyoid ligament & provides sensory superior to vocal folds
Superior Laryngeal
EXTERNAL
Posterior to sternothyroid & then enters to become motor to cricothyroid
Nerve damage → anesthetizes superior larynx & paralyzes cricothyroid
Voice lower & more monotone
Recurrent Laryngeal Nerve
Ascends b/w esophagus & trachea
Becomes inferior laryngeal, enters deeps to inferior constrictor, & motor to all other muscles
L loops around subclavian
R loops around aorta
Unilateral RLN
Unilateral nerve damage → significant voice loss
Bilateral RLN
Bilateral nerve damage → EMERGENCY (both cords paramedian)
