Temporal bone

The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.Occipitomastoid suture. It separates occipital bone and mastoid portion of temporal bone.Squamosal suture. It separates parietal bone and squama portion of temporal bone.Sphenosquamosal suture. It separates sphenoid bone and squama portion of temporal bone.Zygomaticotemporal suture. It separates zygomatic bone and zygomatic process of temporal bone.1. Outer surface of petromastoid part. 2. Outer surface of tympanic ring. 3. Inner surface of squama.Figure 7 : Temporal bone at birth. Outer aspect.Figure 8 : Temporal bone at birth. Inner aspect.Position of temporal bone (green). Animation.Shape of temporal bone (left).Cranial bones.Sphenoid and temporal bones The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. The lower seven cranial nerves and the major vessels to and from the brain traverse the temporal bone. The temporal bone consists of four parts— the squamous, mastoid, petrous and tympanic parts. The squamous part is the largest and most superiorly positioned relative to the rest of the bone. The zygomatic process is a long, arched process projecting from the lower region of the squamous part and it articulates with the zygomatic bone. Posteroinferior to the squamous is the mastoid part. Fused with the squamous and mastoid parts and between the sphenoid and occipital bones lies the petrous part, which is shaped like a pyramid. The tympanic part is relatively small and lies inferior to the squamous part, anterior to the mastoid part, and superior to the styloid process. The styloid, from the Greek stylos, is a phallic shaped pillar directed inferiorly and anteromedially between the parotid gland and internal jugular vein. An elongated or deviated styloid process can result from calcification of the stylohyoid ligament in a condition known as Eagle syndrome. The temporal bone is ossified from eight centers, exclusive of those for the internal ear and the tympanic ossicles: one for the squama including the zygomatic process, one for the tympanic part, four for the petrous and mastoid parts, and two for the styloid process. Just before the end of prenatal development the temporal bone consists of three principal parts: