Squamous part of temporal bone
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The squamous part of the temporal bone (or squamous temporalis/squamous temporal bone) is a very thin bone and forms the anterosuperior aspect of the temporal bone.
The squamous temporal bone's outer convex surface provides attachment to the temporalis muscle and forms a boundary of the temporal fossa. A curved line, the supramastoid crest (or temporal line), runs posterosuperiorly across its posterior part and provides attachment to the temporalis fascia.
The anterior aspect of the squamous temporal bone extends antero-inferiorly as well as laterally to form the zygomatic process. The superior surface of the zygomatic process provides attachment to the temporalis fascia, whereas its inferior surface is rough and thick surface for the attachment of the masseter muscle.
The posterior aspect of the zygomatic process divides into anterior and posterior roots 3. The anterior root is directed medially and ends in the rounded, cartilage-covered, articular eminence, which forms the anterior boundary of the mandibular fossa. The posterior root runs above the external auditory meatus and continues with the supramastoid crest.
The squamous temporal bone is continuous with the mastoid portion of the temporal bone and pneumatization of the mastoid (mastoid air cells) often proceeds to pneumatize the temporal squamosa as well. In fact, embryologically, the squamous and petrous parts of the temporal bone both contribute to formation of the mastoid, coming together at the Koerner septum. Thus, some authors to use the term "squamomastoid" to refer to the combined structure to acknowledge this dual origin 4,5.
The squamous temporal bone articulates with various bones:
- superiorly: parietal bone via the temporoparietal suture
- anteriorly: zygomatic bone through the zygomatic process
- anteroinferiorly: greater wing of the sphenoid bone via the sphenosquamosal suture
- posteriorly: tympanic and petrous parts of temporal bone via the tympanosquamous fissure and petrosquamous fissure, respectively
- 1. Temporal Bone Imaging. Thieme. ISBN:1588904016. Read it at Google Books - Find it at Amazon
- 2. Gray H. Anatomy of the Human Body, 20th edition. (1918) ISBN:1587341026. Read it at Google Books - Find it at Amazon
- 3. Curtin HD, Gupta R, Bergeron RT. "Embryology, anatomy, and imaging of the temporal bone." in Som PM, Curtin HD (Eds.). Head and Neck Imaging. 5th ed. (2011). ISBN: 9780323053556
- 4. Virapongse C, Sarwar M, Bhimani S, Sasaki C, Shapiro R. Computed tomography of temporal bone pneumatization: 1. Normal pattern and morphology. (1985) AJR. American journal of roentgenology. 145 (3): 473-81. doi:10.2214/ajr.145.3.473 - Pubmed
- 5. Virapongse C, Sarwar M, Bhimani S, Sasaki C, Shapiro R. Computed tomography of temporal bone pneumatization: 2. Petrosquamosal suture and septum. (1985) AJNR. American journal of neuroradiology. 6 (4): 561-8. Pubmed