Structure of the Stylomastoid Foramen
- The stylomastoid foramen is located between the styloid and mastoid processes of the temporal bone.
- The average distance between the opening of the stylomastoid foramen and the styloid process is approximately 0.7 mm or 0.8 mm in adults.
- This distance may decrease to around 0.2 mm during aging.
- The stylomastoid foramen transmits the facial nerve.
- It also transmits the stylomastoid artery.

Clinical Significance of the Stylomastoid Foramen
- Inflammation of the facial nerve at the stylomastoid foramen can result in Bell's palsy.
- Bell's palsy is characterised by facial drooping on the affected side.
- Bell's palsy occurs when the facial nerve leaves the skull at the stylomastoid foramen.

Additional Images
- Facial canal
- Lateral head anatomy detail. Facial nerve dissection.

References
- This article incorporates text in the public domain from page 144 of the 20th edition of Gray's Anatomy (1918).
- Krmpotić Nemanić, Jelena; Vinter, Ivan; Ehrenfreund, Tin; Marušić, Ana (2008-12-17). Postnatal changes in the styloid process, vagina processus styloidei, and stylomastoid foramen in relation to the function of muscles originating from the styloid process. Surgical and Radiologic Anatomy. 31 (5): 343. doi:10.1007/s00276-008-0450-2. ISSN 1279-8517.
- Curtin, H D; Wolfe, P; Snyderman, N (October 1983). The facial nerve between the stylomastoid foramen and the parotid: computed tomographic imaging. Radiology. 149 (1): 165–169. doi:10.1148/radiology.149.1.6611924. ISSN 0033-8419.
- Bourdon, Nicolas; Babin, Emmanuel; Moreau, Sylvain; Salame, Ephrem; Valdazo, André; De Rugy, Marc Goullet; Delmas, Pierre (2000-09-01). Facial Nerve: Vascular-Related Anatomy at the Stylomastoid Foramen. Annals of Otology, Rhinology & Laryngology. 109 (9): 849–852. doi:10.1177/000348940010900912. ISSN 0003-4894.
- Anatomy figure: 22:4a-07 at Human Anatomy Online, SUNY Downstate Medical Center
- Anatomy photo: 22:os-0708 at the SUNY Downstate Medical Center
- Anatomy diagram: 34257.000-1.
- Roche Lexicon – illustrated navigator. Elsevier. Archived from the original on 2014-01-01.
- Lesson3 at The Anatomy Lesson by Wesley Norman (Georgetown University) (midearcavity)
- Diagram at patientsforum.com

External Links
- Anatomy figure: 22:4a-07 at Human Anatomy Online, SUNY Downstate Medical Center
- Anatomy photo: 22:os-0708 at the SUNY Downstate Medical Center
- Anatomy diagram: 34257.000-1.
- Roche Lexicon – illustrated navigator
- Diagram at patientsforum.com