Angle of mandible

Angulus mandibulae

  • Synonym: Mandibular angle

Definition

The angle of mandible, also known as the gonial angle, is formed where the posterior edge of the ascending ramus meets the inferior edge of the body of the mandible. This is essentially the part where the lower back portion of the mandible curves upwards. The most standout and prominent point on the angle of mandible is referred to as the gonion.

This angular region is characterized by tough, slanted ridges on each side, which serve as attachment points for the muscles of mastication. The masseter muscle attaches to the outer surface of both the ramus and the angle of mandible, while the medial pterygoid muscle connects to the inner surface of these parts. Additionally, a critical ligament, the stylomandibular ligament, links the angle of mandible to the styloid process at the skull's base.

The angle of mandible decreases as one ages. At birth, it is roughly 160 degrees but changes caused by the development of teeth and the growth and expansion of the jaw lead to a reduction in the mandible's size, bringing the gonial angle down to about 120 degrees in adulthood.

The angle of mandible is typically evaluated using radiographs. It is a significant anthropometric feature which contributes to facial esthetics and mechanics of chewing. A broader gonial angle is linked to a higher chance of fractures at the angle of mandible.

__________________________________________________________________

Text written by Muhammad A. Javaid, MD, PhD © 2024 IMAIOS.

  • Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 8: Head and Neck’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp. 922.

  • Breeland G, Aktar A, Patel BC. Anatomy, Head and Neck, Mandible. [Updated 2023 Apr 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532292/

  • Tiwari P, Bera RN, Chauhan N. Magnitude of Gonial Angle Influence on the Commonness of Mandibular Angle Fractures. Ann Maxillofac Surg. 2020 Jan-Jun;10(1):190-194.


Comparative anatomy in animals

Translations

Translations