Osteology of Head & Neck - Temporal Bone

Temporal bone - a pair or irregular pneumatic bones.
The parts - Squamous
Petro-mastoid
Tympanic
Styloid process

Squamous part - presents
External surface
Internal surface
Superior border
Antero inferior border

External surface forms floor of temporal fossa
gives attachment to temporlis muscle
extends 1.5 cms below the supramastoid crest
External surface shows zygomatic process with anterior and posterior roots.
It unites with temporal process of zygomatic process completing zygomatic arch
Upper border of zygomatic arch gives attachment to galea aponeurotica, temporal fascia
Lower border and inner surface gives attachment to masseter muscle

Internal Surface or cerebral surface shows impressions of gyri of temporal lobes of cerebrum, impressions of middle temporal vessels
Superior border articulates with middle 1/3 of lower border parietal bone
Anteroinferior border articulates with squamous part of greater wing of sphenoid

Mastoid part - presents External surface, inner surface
superior & posterior border and a mastoid process
External Surface give attachment to Sternocleidomastoid muscle, splenius capitis, longissimus capitis muscles from before backwards
It presents mastoid foramen which transmits emmissary vein connecting the sigmoid sinus with the posterior auricular vein.
Internal surface presents sulcus for sigmoid sinus
superior border articulates with posterior 1/3 of lower border of parietal bone
Posterior border articulates with lateral border of occipital bone

Tympanic Part presents anterior & Posterior surfaces
Superior inferior & lateral borders
Anterior surface forms the non articular part of mandibular fossa
Posterior surface forms anterior wall , floor & lower part of external acoustic meatus
Superior border meets the squamous part at the squamotympanic fissure
This fissure is divided by the downturned edge of tegmen tympani into petrotympanic fissure and petro squamous fissure
Structures passing through the petro tympaic fissure - Chorda tympani nerve, anterior tympanic artery, anterior ligament of malleus
Inferior border splits to enclose the styloid process (vaginal process)
Lateral border forms the bony ring where cartilage of ear are attached

Petrous part Presents anterior, posterior & inferior surfaces
anterior, superior & posterior borders
An apex & a base
The apex is irregular, presents an impressions for trigeminal ganglion, covered by meckel's cave.
It also shows the anterior opening of carotid canal.
It forms the posterolateral boundary for the foramen lacerum
The base blends with squamous & mastoid part

Anterior surface presents
arcuate fossa, tegmen tympani
Posterior surface presents internal acoustic meatus, oblique slit - vestibule of aqueduct, subarcuate fossa
Inferior surface presents attachments to levator veli palatini , lateral to this forms sulcus tubae along with greater wing of sphenoid which lodges the cartilaginous part of auditory tube
Lateral to this is the jugular fossa which lodges the supeior bulb of internal jugular vein
infront to this fossa presents impression of inferior ganglion of glossopharyngeal nerve
Styloid process - downward projection of 2.5 cms long - develop from the dorsal part pharyngeal arch
It gives attachment to 3 muscles - styloglossus, stylopharyngeus, stylohyoid muscles
2 ligaments - stylohoid & stylomandibular ligament
Related laterally to parotid gland with external carotid artery & facial nerve
medially related to internal jugular vein & internal carotid artery with last four cranial nerves inbetween them Follow me in blogspot - https://human-anatomylessons.blogspot... _________________________________________________________________________________________________________________ Visit my blogs - https://humananatomyonline.in/
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