Norma LATERALIS of skull

1. SUBMITTED TO :-
Submitted by:-

2. BONES
 FRONTAL
 PARIENTAL
 OCCIPITAL
 TEMPORAL
 SPHENOID
 ZYGOMATIC
 MANDIBLE
 MAXILLA
 NASAL

3. 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 temporal.this crest is continuous ant. with the
post. root of the zygomatic arch.

4. 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 zygomatico-
temporal suture crosses the arch obliquely downwards
& backwards.

5. 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 bone. The margins are roughened for the
attachment of auricular cartilage.

6. 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.

7. 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 the second
year of life. The mastoid foramen lies at or near the
occipitomastoid suture.

8. Styloid process
The styloid process is a needle – like thin , long
projection from the norma basalis situated
anteromedial to the mastoid process.

9. 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.
Anterior wall - is formed by the zygomatic bone & by
parts of the frontal & sphenoid bones.

10. 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 frontozygomatic suture.

11. 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.
Lateral – Ramus of mandible.

12. 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.
c) Deep temporal nerves.

13. 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.
3. The zygomaticotemporal foramen transmits the
nerve of the same name & minute artery.

14. Thanking you……