ANAT2020: Clinical Anatomy 4 - OP Landmarks of the Skull

location of the inion / external occipital protuberance

most palpable central prominence on posterior skull

the inion / external occipital protuberance serves as an attachment site for what ligament

nuchal ligament

location of external occipital crest

descends from inion to foramen magnum (can be difficult to palpate as the nuchal ligament & suboccipital m.m cover it)

external occipital crest serves as an attachment site for what ligament

nuchal ligament

location of superior nuchal line

lateral ridge forming superior limit of neck region

superior nuchal line serves as an attachment for what muscles

upper trapezius & sternocleidomastoid

location of mastoid process of temporal bone

posterior / inferior to external auditory meatus

mastoid process of temporal bone serves as an attachment for what muscles

occipitalis, SCM, splenius capitis, posterior belly of digastric, & longissimus capitis

location of styloid process of temporal bone

between angle of mandible and mastoid process; just inferior to external auditory meatus

what role does the styloid process of the temporal bone have in swallowing and speech

attachment for many muscles and ligaments which facilitate movement of the throat, jaw, and tongue

boundaries of the temporal fossa

superiorly the superior and inferior temporal lines, anteriorly by frontal and zygomatic bones, and inferiorly by zygomatic arch

what important structures are housed within the temporal fossa

temporal muscle belly and temporal arteries, veins, and nerves

location of mandibular body

horizontal part of lower jaw bone

what important passage does the mandibular body contain and what does it transmit

mental foramen; transmits mental nerve & vessels

location of mandibular ramus

lateral, vertical portion of mandible

mandibular ramus is the attachment for what group of facial muscles

muscles of mastication

location of mandibular angle

angle between mandibular ramus and body of mandbile

measurement of the degree of mandibular angle and normal what is the normal range in adults

gonial angle; ~120-130 degrees

location of mental protuberance

inferior aspect of mandibular symphysis, forms prominence of chin

mental protuberance is created by fusion of what structure in the first year of life

mandibular symphysis

where is the temporal pulse felt

over the temporal fossa

what artery is felt at the temporal pulse and what does it supply

superficial temporal artery; supplies blood to scalp and face

location of frontal bone

spans from nasal bridge and superior orbital, superiorly to coronal suture

importance of the frontal bone

forms the forehead, contains frontal sinus, and protects frontal lobes of the brain

location of lambda

junction of lambdoid and sagittal sutures

what is the significance of the lambda in early development

forms the posterior fontanelle - a triangular shaped gap at the back of an infants skull, allowing for it to mold during birth; closes within 6-8 weeks of life

location of bregma

junction of coronal and sagittal sutures

significance of the bregma in early development

forms the anterior fontanelle - larger of two fontanelles, diamond shaped gap which allows skull to mold during birth; typically closes between 12-24 months of life

what bones articulate to form the coronal suture

frontal and parietal bones

what bones articulate to form the sagittal suture

right and left parietal bones

what bones articulate to form the lambdoid suture

occipital, parietal, and temporal bones

what structure lies where sagittal and coronal sutures converge and what is the significance of this space during infancy

bregma; forms anterior fontanelle which allows the skull to mold during birth

the sagittal suture converges with both coronal and lambdoid sutures to form what two structures, and what is the significance of this during early development

bregma (anterior fontanelle in infancy) and lambda (posterior fontanelle)

significance of the lambdoid suture during infancy

converges with sagittal suture to form lambda (posterior fontanelle in infancy)

location of maxilla

spans from nasal bone and inferior orbital region to upper teeth

location of alveolar process of the maxilla

thickened ridge located along inferior surface of maxilla, housing the upper teeth

significance of the maxilla in breathing

forms the anterior hard palate, separating the oral and nasal cavities, which is essential for proper breathing and speech

what two processes form the zygomatic arch

temporal process of zygomatic bone anteriorly and zygomatic process of temporal bone posteriorly

zygomatic arch serves as an attachment site for what muscles and what is their primary function

masseter and temporalis, essential for mastication

location of nasal bone

rectangle shaped bone with superior borders and main bodies of bone forming bridge of nose and inferior borders connect with nasal cartilage to form superior margin of nasal cavity

what cavity does the nasal bone form

nasal cavity; nasal bone protects it from external factors

location of alveolar process of mandible

superior portion of mandibular body, forming a horse-shoe shaped ridge that contains tooth socks of lower teeth

function of the alveolar process of the mandible

contains sockets of lower teeth, providing necessary support to prevent tooth mobility and/or loss

location of coronoid process of mandible

thin, triangular projection arising from superior part of ramus of mandible, anterior to condylar process with mandibular notch between

coronoid process serves as a muscle attachment for

temporalis insertion

location of condylar process (temporomandibular joint)

projection at the posterior end of the mandible, above the neck of the mandible and behind the coronoid process; articulates with the temporal bone at the TMJ

condylar process articulates with what bone to form the TMJ, and what processes is this joint vital in

temporal bone; chewing and speaking

location of mental foramen

posterior aspect of mandible, near the midline of the body, at the junction of the mandibular body and ramus (normally around the region of the wisdom teeth)

significance of mental foramen

passage for mental nerve and vessels which provide sensation and blood supply to chin and lower lip

location of laryngeal prominence

two laminae fuse at an angle on the thyroid cartilage to form the “Adam’s Apple”

significance of thyroid cartilage and laryngeal prominence

protects and supports vocal cords, participating in voice production & modulation

location of thyroid cartilage

inferior to hyoid bone, superior border at level of C4

location of cricoid cartilage

inferior to thyroid cartilage at level of C6; junctions of larynx and trachea, pharynx, and esophagus

significance of cricoid cartilage

supports vocal cords, protects airway, forms lower boundary of larynx

location of thyroid gland

at the level of C5-T, inferolateral to thyroid / cricoid cartilage; anterolateral to larynx and trachea

location of isthmus

central portion where left and right lobes of thyroid gland join, directly inferior to cricoid

significance of thyroid gland

releases thyroid hormone which regulates metabolism, heart rate, and body temperature

location of tracheal rings

inferior to cricoid cartilage and thyroid; first ring palpable just above jugular notch

significance of tracheal rings

incomplete posteriorly to allow trachea to expand during swallowing; ensures open airway for breathing

location of carotid pulse

lateral to trachea, medial to SCM, at the level of cricoid cartilage

significance of carotid pulse

carotid artery passes here, supplying blood to brain, face, and neck

location of cervical lymph nodes

superficial and superior deep chains palpable anterior to SCM; inferior deep chain palpable posterior to SCM

significance of cervical lymph nodes

receive lymph from head and neck

location of submandibular nodes

inferior to mandible

significance of submandibular nodes

drain lymph from cheeks, upper lip, lower lateral lip, gums, tongue, etc.

parotid gland location

external surface of angle of mandible; inferior to infratemporal fossa

significance of parotid gland

largest of the salivary glands

location of hyoid bone

level of C2 / C3, inferior to mental prominence, anterior to angle of the mandible; can be felt with swallowing

significance of hyoid bone

only bone that does not articulate with another bone, instead being suspended by muscles and ligaments

location of facial pulse

slight depression on lower border of mandible just anterior to masseter muscle

significance of facial pulse

facial artery passes here, supplies muscles and skin of face