Topic
-NORMA LATERALIS
SUBMITTED TO
:-Submitted
BONES
FEATURES
TEMPORAL LINES
The temporal lines have been studied in the norma verticalis. The inferior temporal line, in its posterion part, turns downwards &
forewards & becomes continues with the
supramastoid crest on the squamous temporal bone near its junction with the mastoid
Zygomatic arch or zygoma
The zygomatic arch is a horizontal on the side of the head, in front of the ear, a little
above the tragus. It is formed by the temporal process of the zygomatic bone is ant.
one-third & the zygomatic process of the temporal bone in post. two –thirds. The
External acoustic meatus
The external acoustic meatus opens just below the post. part of the posterior root of zygoma, its ant. & inferior margin are formed by the tympanic plates, & the posterosuperior magin is formed by the squamous temporal
Masteriod part of the temporal
bone
The mastoid part of the temporal bone lies just behind the external acoustic meatus. It is
continuous antero- superiorly with the squamous temporal bone.
The mastoid temporal bone articulates postero-sup. with the posterinferior part of the parietal bone at the horizontal parietomastoid suture,& post. with the squamous occipital bone at the occipitomastoid suture. These two sutures meet at the lateral end of the lambdoid suture.
The asterion is the point where the
parietomastoid , occipitomastoid & lambdoid suture meet. The mastoid process is a breast like projection from the lower part of the
mastoid temporal bone, postero-inferior to the external acoustic meatus. It appears during
Styloid process
The styloid process is a needle – like thin , long projection from the norma basalis situated
Temporal fossa
Boundaries
Above –
by the superior temporal line.
Below –
by the upper border of the zygomatic arch laterally, & by the infratemporal crest of the greater wing of the sphenoid bone medially.floor
The ant. part of the floor is crossed by an H-shaped suture where four bones, frontal,
parietal, greater wing of sphenoid & temporal adjoin each other.
This area is termed the pterion. It lies 4 cm above the midpoint of the zygomatic arch & 2.5 behind the
Infratemporal fossa
It is an irregular space below zygomatic arch.
Boundaries
Ant. –
post. Surface of body of maxilla.Roof –
infratemporal surface of greater wing of sphenoid.Medial –
lateral pterygoid plate & pyramidal process of palatine bone.Pterygopalatine fossa
This is small pyramidal space situated deeply, below the apex of the orbit.
Attachments
1. The temporal fascia is attached to the superior temporal line & to the area between the two temporal lines.
2. The medial surface & lower border of the zygomatic arch give origin to the masseter.
3. The gap between the zygomatic arch & the side of the skull transmits
a) Tendon of the temporalis muscle. b) Deep temporal vessels.
Structure passing through
foramina
1. The tympanomastoid fissure on the ant. aspect of the base of the mastoid process transmits the auricular branch of vagus nerve.
2. The mastoid foramen transmits :- a) An emissary vein connecting
the sigmoid sinus with the post. auricular vein. b) A
meningeal branch of the occipital artery.
