Back To Search Results

Anatomy, Head and Neck, Digastric Muscle

Editor: Bruno Bordoni Updated: 5/16/2023 11:05:48 PM


The digastrics are a pair of muscles individually made up of two distinct muscle bellies: the anterior and posterior digastrics. They derive embryonically from the first and second pharyngeal arches. Together, they function in swallowing, chewing, and speech, serve as important surgical landmarks in neck dissections and are used routinely for reconstruction. Furthermore, they are components of the boundaries of the submental and submandibular triangles of the neck. There are numerous anatomical variants of the digastrics which can be misleading on MRI or CT. Careful consideration of these variations is critical in clinical assessment and surgical planning. 

Structure and Function

Register For Free And Read The Full Article
Get the answers you need instantly with the StatPearls Clinical Decision Support tool. StatPearls spent the last decade developing the largest and most updated Point-of Care resource ever developed. Earn CME/CE by searching and reading articles.
  • Dropdown arrow Search engine and full access to all medical articles
  • Dropdown arrow 10 free questions in your specialty
  • Dropdown arrow Free CME/CE Activities
  • Dropdown arrow Free daily question in your email
  • Dropdown arrow Save favorite articles to your dashboard
  • Dropdown arrow Emails offering discounts

Learn more about a Subscription to StatPearls Point-of-Care

Structure and Function

The neck contains a pair of digastric muscles, each of which subdivides into an anterior and posterior belly. The two bellies connect by an intermediate tendon. The anterior belly of the digastric attaches near the midline of the base of the mandible on the digastric fossa and runs toward the hyoid. The posterior belly attaches to the temporal bone at the mastoid process and slopes to meet the intermediate tendon. The intermediate tendon typically courses through the stylohyoid muscle, but variations are found lying medial or lateral to it. The tendon runs through a fibrous loop attached to the hyoid bone at the body and greater cornu.[1]

The anterior belly of the digastric divides the submental and submandibular triangles of the neck. The submandibular triangle, bordered by the anterior and posterior bellies of the digastric and the inferior border of the mandible, houses the submandibular gland, anterior facial vein, submental artery, mylohyoid nerve and vessels, and the external carotid. The submental triangle is bordered laterally by the anterior belly and houses lymph nodes that drain the floor of the mouth and part of the tongue.[2] The posterior belly of the digastric also serves as a boundary for the carotid triangle, which is where the facial artery branches from the external carotid.[3]

The digastric muscle functions during swallowing, chewing, and speech. The anterior belly of the digastric is one of the three suprahyoid muscles which stabilizes the hyoid during swallowing, an action critical in protecting the airway while eating. Furthermore, the digastrics work to depress the mandible for jaw opening, chewing, and speech.[4] The contraction of the posterior digastric muscle participates in the extension of the head.

The infrahyoid muscles are the antagonistic muscles to the digastric.


The embryologic period occurs during the first eight weeks following fertilization. During this time, neural crest cells migrate caudally to form the five pharyngeal arches. The first and second pharyngeal arches give rise to the anterior and posterior bellies of the digastrics as well as their respective nerve supplies. The anterior belly of the digastric and the mylohyoid nerve form from the first pharyngeal arch, also known as the mandibular arch. The posterior belly of the digastric and the facial nerve derives from the second pharyngeal arch or the hyoid arch.

Other muscular structures derived from the first pharyngeal arch include the mylohyoid, tensor veli palatini, tensor tympani, and mastication muscles, including the temporalis, masseter, and medial and lateral pterygoids. In addition to the posterior belly of the digastric, the second pharyngeal arch gives rise to the stapedius, buccinator, auricular, occipitofrontalis, facial muscles, platysma, and stylohyoid muscles.[5] Researchers postulate that the wide array of anatomical variants of the anterior belly of the digastric is mostly a result of the complex morphogenesis of the first pharyngeal arch.[1]

Blood Supply and Lymphatics

The submental artery, a branch of the facial artery, supplies blood to the anterior belly of the digastric. It runs between the submandibular gland and mylohyoid muscle. The posterior auricular and occipital branches of the external carotid artery supply blood to the posterior belly of the digastric.[5]


The anterior belly of the digastric receives innervation from the mylohyoid nerve. The mylohyoid nerve is a branch of the inferior alveolar nerve, which arises from the mandibular branch of the trigeminal nerve.[5] It branches off before the inferior alveolar nerve penetrates the mandibular foramen and courses through the mylohyoid canal before giving off motor branches to both the mylohyoid muscle and anterior belly of the digastric muscle.[6] The facial nerve provides nerve supply to the posterior belly of the digastric. 


The lateral face of the posterior belly is in relationship with the sternocleidomastoid muscles, very long neck muscle, and splenius capitis; the medial face is related to the lateral rectus muscle of the head.

The anterior belly is laterally covered by the skin planes and the platysma muscle while, medially, it rests on the mylohyoid muscle.

Physiologic Variants

The anterior belly of the digastric is more likely to have anatomical variations than the posterior belly; variations of the anterior belly of the digastric occur in up to 65.8% of the population. Of those reported, it is far more likely to have unilateral than bilateral variants. Many of these variants are accessory muscle bellies with varying origins and insertions. Reports also exist of variations of the nerve supply in which the anterior belly receives innervation from both the facial nerve and mylohyoid nerve.[7] There are no confirmed clinical consequences of these variants.[5] The intermediate tendon may not pierce the stylohyoid muscle but may lean over or laterally.

Surgical Considerations

The digastrics serve as a significant surgical landmark in neck dissections; the posterior belly is used to help identify the course of the spinal accessory nerve, internal jugular vein, carotid arteries, and hypoglossal nerve. It can also help identify ansa cervicalis in reconstruction cases. The anterior belly of the digastric is often included in submental flaps during facial reconstruction, as the submental vessels frequently course deep to the muscle. The intermediate tendon of the digastric can be attached to the tongue to help avoid stridor and subsequent need for tracheostomy in patients who undergo resection of the anterior mandibular arch. The digastrics may be used as a flap to restore a symmetrical smile to those with injury to the marginal mandibular branch of the facial nerve.[5] The digastric can be sutured to the mandible in neck dissections for primary tongue cancer resection to accomplish laryngeal suspension.[8]

Clinical Significance

Careful consideration of anatomical variations should be taken during clinical evaluation and surgical planning so as not to be mistaken for a neck mass. Knowledge of this possible occurrence is important for both the surgeon and the radiologist. The digastric muscles may be implicated in post-radiation dysphagia or swallowing dysfunction.[9] Post-radiation changes leading to atrophy or fibrosis of the digastric is a possible sequela in patients who have undergone postoperative radiotherapy for oral cancer.[10]

Exercises targeting the suprahyoid muscles, including the anterior belly of the digastric, are thought to help patients with dysphagia.[11][12]

Calcification of the digastric muscle may be the cause (together with an alteration of the styloid ligament, such as length or calcification) of styloid process neuralgia; the latter is also known by the name long styloid process syndrome or Eagle syndrome. Muscle calcification could cause various symptoms, such as throat disorders, ear pain, and pharyngeal pain. The patient may have pain during tongue or head movements. In most clinical cases, surgery is necessary.

The digastric muscle is involved in the causes of pain relative to bruxism or the habit of clenching teeth. A myofunctional physiotherapy or speech therapy can reduce the electrical activity of the muscle during the movement of the jaw and reduce pain.

The digastric muscle in its posterior portion could be the site of a rare complication of otitis media: a Citelli abscess. The resolution is surgical.

The presence of trigger points in the digastric muscle can cause referred pain to the teeth. The therapy is of myofunctional type.

Other Issues

There are few reports of intramuscular hemangiomas of the digastric muscles.[13] In a very small percentage of people, agenesis of the anterior belly is an anomaly.


(Click Image to Enlarge)
<p>Neck Anatomy

Neck Anatomy. Neck anatomy illustration includes anterior triangle, m. mylohyoideus, mandibula, m. digastricus, submental triangle, submandibular triangle, carotid triangle, muscular triangle, m. omohyoideus (venter superior), m. sternocleidomastoideus, processus mastoideus, os hyoideum, m. scalenus medius, m. scalenus anterior, m. omohyoideus (venter inferior), m. trapezius, and clavicula.

Contributed by Beckie Palmer

(Click Image to Enlarge)
<p>Muscles Of the Neck, Mandible, Mastoid Process, Clavicle, Trapezius, Sternocleidomastoideus, Sternohyoideus, Omohyoideus B

Muscles Of the Neck, Mandible, Mastoid Process, Clavicle, Trapezius, Sternocleidomastoideus, Sternohyoideus, Omohyoideus Belly, Scalenus Anterior and medius, Levator Scapulae, Splenius, Mylohyoideus, Hyoid bone, Thyrohyoideus, Digastricus, Stylohyoideus

Henry Vandyke Carter, Public domain, via Wikimedia Commons

(Click Image to Enlarge)
<p>Supra and Infrahyoid muscles, Hyoid Bone, Clavicle, Styloglossus, Hyoglossus, Geniohyoideus, Mylohyoideus, Digastricus, St

Supra and Infrahyoid muscles, Hyoid Bone, Clavicle, Styloglossus, Hyoglossus, Geniohyoideus, Mylohyoideus, Digastricus, Stylohyoideus, Omohyoideus, Sternothyroideus, Sternohyoideus, OmoHyoideus, Sternocleidomastoideus, Trapezius, OmoHyoideus

Henry Vandyke Carter, Public domain, via Wikimedia Commons

(Click Image to Enlarge)
The image shows the shape of the digastric muscle.
The image shows the shape of the digastric muscle.
Contributed by Bruno Bordoni, PhD



Hsiao TH, Chang HP. Anatomical variations in the digastric muscle. The Kaohsiung journal of medical sciences. 2019 Feb:35(2):83-86. doi: 10.1002/kjm2.12012. Epub     [PubMed PMID: 30848024]


Singh M, Vashistha A, Chaudhary M, Kaur G. Forgotten triangles of neck. Annals of maxillofacial surgery. 2016 Jan-Jun:6(1):91-3. doi: 10.4103/2231-0746.186149. Epub     [PubMed PMID: 27563614]


Meegalla N, Sood G, Nessel TA, Downs BW. Anatomy, Head and Neck: Facial Arteries. StatPearls. 2023 Jan:():     [PubMed PMID: 30725617]


Sowman PF, Flavel SC, McShane CL, Sakuma S, Miles TS, Nordstrom MA. Asymmetric activation of motor cortex controlling human anterior digastric muscles during speech and target-directed jaw movements. Journal of neurophysiology. 2009 Jul:102(1):159-66. doi: 10.1152/jn.90894.2008. Epub 2009 May 6     [PubMed PMID: 19420123]


Kim SD, Loukas M. Anatomy and variations of digastric muscle. Anatomy & cell biology. 2019 Mar:52(1):1-11. doi: 10.5115/acb.2019.52.1.1. Epub 2019 Mar 29     [PubMed PMID: 30984445]


Choi P, Iwanaga J, Dupont G, Oskouian RJ, Tubbs RS. Clinical anatomy of the nerve to the mylohyoid. Anatomy & cell biology. 2019 Mar:52(1):12-16. doi: 10.5115/acb.2019.52.1.12. Epub 2019 Mar 29     [PubMed PMID: 30984446]


Kawai K, Koizumi M, Honma S, Tokiyoshi A, Kodama K. Derivation of the anterior belly of the digastric muscle receiving twigs from the mylohyoid and facial nerves. Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 2003 Jan:185(1):85-90     [PubMed PMID: 12597132]


Ohkoshi A, Ogawa T, Sagai S, Nakanome A, Higashi K, Ishii R, Kato K, Katori Y. Simple laryngeal suspension procedure by suturing the digastric muscle to the periosteum of the mandible in neck dissection for tongue cancer. American journal of otolaryngology. 2018 Mar-Apr:39(2):77-81. doi: 10.1016/j.amjoto.2018.01.008. Epub 2018 Jan 31     [PubMed PMID: 29395281]


Gawryszuk A, Bijl HP, Holwerda M, Halmos GB, Wedman J, Witjes MJH, van der Vliet AM, Dorgelo B, Langendijk JA. Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 1: Physiology and anatomy. Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2019 Jan:130():62-67. doi: 10.1016/j.radonc.2018.10.028. Epub 2018 Nov 9     [PubMed PMID: 30420235]


Kim J, Shin ES, Kim JE, Yoon SP, Kim YS. Neck muscle atrophy and soft-tissue fibrosis after neck dissection and postoperative radiotherapy for oral cancer. Radiation oncology journal. 2015 Dec:33(4):344-9. doi: 10.3857/roj.2015.33.4.344. Epub 2015 Dec 30     [PubMed PMID: 26756035]


Shen SC, Nachalon Y, Randall DR, Nativ-Zeltzer N, Belafsky PC. High elevation training mask as a respiratory muscle strength training tool for dysphagia. Acta oto-laryngologica. 2019 Jun:139(6):536-540. doi: 10.1080/00016489.2019.1605196. Epub 2019 Apr 29     [PubMed PMID: 31035838]


Wada S, Tohara H, Iida T, Inoue M, Sato M, Ueda K. Jaw-opening exercise for insufficient opening of upper esophageal sphincter. Archives of physical medicine and rehabilitation. 2012 Nov:93(11):1995-9. doi: 10.1016/j.apmr.2012.04.025. Epub 2012 May 10     [PubMed PMID: 22579648]


Clement WA, Graham I, Ablett M, Rawlings D, Dempster JH. Intramuscular hemangioma of the posterior belly of the digastric muscle failing to highlight on magnetic resonance imaging. The Annals of otology, rhinology, and laryngology. 2002 Nov:111(11):1050-3     [PubMed PMID: 12450183]

Level 3 (low-level) evidence


Bhat NP, Sumalatha S, Shetty A, Prabhath S. A clinical perspective on the anatomical study of digastric muscle. Anatomy & cell biology. 2023 Oct 6:():. doi: 10.5115/acb.23.043. Epub 2023 Oct 6     [PubMed PMID: 37798015]

Level 3 (low-level) evidence