We covered pterion anatomy into below points.
1. Fontanelle- Pterion
2. Location- Temporal fossa
4. Artery- Middle meningeal artery
5. Nerve- Auriculotemporal nerve
7. Surgical landmark
1. In pediatrics we read four fontanelle-
A. Anterior fontanelle or Bregma
B. Posterior fontanelle or Lambda
C. Anterolateral fontanelle or Pterion
D. Posterolateral fontanelle or Asterion
Mnemonic: PLAB (Pterion, Lambda, Asterion, Bregma)
We are only discussing pterion here.
It is present on anterolateral side of skull. (See figure)
Medial boundary or floor of temporal fossa is called pterion.
Four skull bones (Frontal, parietal, temporal, and sphenoid) meet at this area and form H-shape suture. (See Fig.)
Anterior division of middle meningeal artery (MMA) are present beneath the pterion therefore, there may be damage to the middle meningeal artery (Anterior division) due to fracture in this area.
NOTE- Middle meningeal artery is the branch of 1st part of maxillary artery (terminal branch of external carotid artery).
MMA is related with auriculotemporal nerve (two root of AT nerve surround MMA).
Auriculotemporal nerve (AT nerve) is arise from posterior division of trigeminal nerve or 5th cranial nerve (Mandibular division).
Branches of Auriculotemporal nerve are important in clinical point of view because of if AT nerve damage occurs, we can trace its symptoms through its branches (given below).
Auriculotemporal nerve branches-
A. Auricular branch– to ear
B. Articular branch– for Temporomandibular joint (TMJ).
C. Superficial temporal branch– supply to the skin of temple region.
D. Secretomotor branch– to the parotid gland through otic ganglion (parasympathetic ganglion).
Due to fracture middle meningeal artery is ruptured and blood collect (Hematoma) in the beneath of pterion.
Clot compress the brain tissue and it is dangerous for life.
7. Surgical landmark-
It is also a surgical landmark in case of cerebral artery aneurysm.
Neurosurgeon enter into brain through this area.
This is the weak area of of skull and generally fractured in trauma (Car accident and Head injury).