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

Stylomastoid foramen (Wikipedia)

The stylomastoid foramen is a foramen between the styloid and mastoid processes of the temporal bone of the skull. It is the termination of the facial canal, and transmits the facial nerve, and stylomastoid artery. Facial nerve inflammation in the stylomastoid foramen may cause Bell's palsy.

Stylomastoid foramen
Base of skull. Inferior surface. Pink region is temporal bone, and stylomastoid foramen is in black circle at center of pink region.
Left temporal bone. Inferior surface. (Stylomastoid foramen is third label from the bottom on the left.)
Details
Part of	temporal bone of skull
System	skeletal
Identifiers
Latin	foramen stylomastoideum
TA98	A02.1.06.048
TA2	684
FMA	55816
Anatomical terms of bone [edit on Wikidata]