The digastric is a two-bellied suprahyoid muscle with different embryological origins and nerve supplies for each belly. The posterior belly (branchial arch 2 origin, facial nerve) is used as a landmark during neck dissection. The posterior digastric belly marks the posterior limit of the submandibular triangle and the position of the facial nerve as it exits the parotid. The anterior belly is used for digastric flap reconstruction.
An expanded entry for Digastric.
| Origin | Anterior belly: digastric fossa of the mandible (inner surface near the symphysis). Posterior belly: mastoid notch (medial to the mastoid process) |
|---|---|
| Insertion | Intermediate tendon attached to the hyoid bone via a fibrous loop. The central tendon connects the two bellies |
| Nerve Supply | Anterior belly: mylohyoid nerve (branch of the inferior alveolar nerve, V3). Posterior belly: facial nerve (VII), the only non-facial muscle supplied by the facial nerve |
| Blood Supply | Anterior belly: submental artery. Posterior belly: posterior auricular and occipital arteries |
| Actions |
|
|---|
It depresses the mandible to open the mouth and elevates the hyoid bone during swallowing and speech.
The posterior digastric belly is the key surgical landmark in neck dissection and parotidectomy: the facial nerve exits the stylomastoid foramen immediately deep and medial to the posterior digastric origin. The sternocleidomastoid, posterior digastric, and stylohyoid form the boundaries identifying the nerve trunk. The digastric's intermediate tendon is fixed to the hyoid, limiting its contraction amplitude.
The anterior belly of the digastric is palpable beneath the chin in the submental triangle during resisted jaw opening. The posterior belly is deep to the sternocleidomastoid and not palpable from the surface.
Posterior digastric belly used as the primary surgical landmark for locating the facial nerve at the stylomastoid foramen during parotidectomy.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
