Summary of Lateral longitudinal arch

Lateral longitudinal arch

It is composed of the calcaneus, the cuboid, and the fourth and fifth metatarsals

It  is lower than the medial  longitudinal arch.

It is formed by less bone and joint

It is less mobile

It commonly bears body weight

The peak of the lateral longitudinal arch is located at the level of articular facets on the superior outermost layer of the calcaneum (i.e., at the level of subtalar joint).


The posterior column of the lateral longitudinal arch is composed by the lateral tubercle of the calcaneum and the anterior column is composed by the heads of the lateral 2 metatarsals.


The primary joint of the lateral longitudinal arch is calcaneocuboid joint.

Summary of medial longitudinal arch

Medial longitudinal arch

It is made up by the calcaneus, the talus, the navicular, the three cuneiforms (medial, intermediate, and lateral), and the first, second, and third metatarsals

The medial arch is higher than the lateral longitudinal arch.

It is formed by more bones and joints

It is more mobile

It acts as shock absorber 

Summit: 

Its summit is at the superior articular surface of the talus

Pillars: 

• The medial half of the calcaneum creates the posterior column of the medial longitudinal arch.
• The heads of the medial 3 metatarsals create the anterior column of the medial longitudinal arch.

Joints:
The key joints of the medial longitudinal arch are talocalcaneonavicular and subtalar

Sphenoid: easy and brief discussion

Sphenoid

Parts of sphenoid :

1.     Body

2.     Lesser wings

3.     Greater wings

4.     Pterygoid processes

Body of sphenoid

Body of sphenoid has 6 surfaces

•      Superior

•      Lateral

•      Anterior

•      Inferior

•      Posterior

Superior surface of body of sphenoid

Identify following structures

From before backward

1.     Ethmoidal spine

2.     Jugum sphenoidale

3.     Sulcus chiasmatis

4.     Tuberculum sellae

5.     Sella turcica

6.     Middle clinoid processes

7.     Clivus 

Indentify following structure on the anterior  surface of body of sphenoid

1.     Sphenoidal crest

2.     Shenoidal air sinuses

Identify following foramen / fissure of sphenoid

1.     Superior orbital fissure

2.     Optic canal

3.     Foramen rotundum

4.     Foramen ovale

5.     Foramen spinosum 

Sphenoid bone articulate with following bone

1.     Ethmoid

2.     Frontal

3.     Parietal

4.     Petrous and squamous part of temporal bone

5.     Palatine bone

6.     Occipical bone 

Maxilla : easy and brief discussion

Maxilla :

•      2^nd largest bone of face

•      2 maxillae forms whole of upper jaw

•      Each maxilla contributes in formation of

1.      Face

2.      Nose

3.      Mouth

4.      Orbit

5.      Infra-temporal fossa

6.      Pterygopalatine fossa

•      Each maxilla has

•      A body

•      4 processes

1.      Frontal

2.      Zygomatic

3.      Alveolar

4.      Palatine

•      Body of maxilla

•      Shape pyramidal

•      It has

•      Base directed at nasal surface

•      Apex directed laterally at zygomatic process

•      4 surfaces

1.      Superior / orbital

2.      Anterior / facial

3.      Posterior / infratemporal

4.      Medial /nasal

•      Encloses a cavity  maxillary sinus