Anat Cell Biol.  2023 Dec;56(4):441-447. 10.5115/acb.23.043.

A clinical perspective on the anatomical study of digastric muscle

• Bhat NP
• Sumalatha S
• Shetty A
• Prabhath S

• KMID: 2548896
• DOI: http://doi.org/10.5115/acb.23.043

Abstract

One of the suprahyoid muscles is the digastric muscle which comprises anterior and posterior bellies joined by an intermediate tendon. Because of its close relationship with the submandibular gland, lymph nodes, and chief vessels of the neck, detailed knowledge about the morphometry of the digastric muscle is essential. The objective of the current crosssectional evaluative study is to record morphometry along with the digastric muscle’s origin, insertion, and variability. Forty human cadavers (25 males and 15 females) were dissected, and the head and neck regions were studied in detail. The attachment of the digastric muscle anterior belly to the digastric fossa of the mandible was noted, and the distal attachment of the posterior belly to the mastoid notch was traced. The length of the anterior belly from the digastric fossa to its intermediate tendon and the length of the posterior belly from the intermediate tendon to its mastoid attachment were measured. There is a fair correlation between the length of the neck and the length of the anterior and posterior belly. The study also identified two cases of bilateral accessory bellies of the anterior belly of the digastric. Normal morphometric data is provided by this study on details of the digastric muscle. It is significant from a clinical and surgical point of view as the muscle lies in proximity to the important structures of the neck.

Keyword

Digastric muscle; Anterior belly; Posterior belly; Morphometry; Variation

Figure

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  Fig. 1 Representative image of the normal digastric muscle and the measurements considered. (A) Representative image of the normal digastric muscle. (B) Red continuous lines denote the lengths of the AB (1), PB (2), and IT (3). Red dotted lines denote the bony measurements between the SM, HY, and MP. SM, symphysis menti; AB, anterior belly; HY, hyoid bone; SG, submandibular gland; IT, intermediate tendon; PB, posterior belly of digastric, MP, mastoid process.

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  Fig. 2 Figure showing bilateral accessory anterior belly of digastric muscle. (A) Acc B are bilaterally inserted into the lateral part of the hyoid bone. (B) Acc B are bilaterally inserted into the intermediate tendon of the digastric muscle. AB, anterior belly; Acc B, accessory anterior belly; MH, mylohyoid muscle; SM, submental lymph node; SV, submental vein; SA, submental artery; SG, submandibular gland; HY, hyoid bone.

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  Fig. 3 Comparison between the morphometric measurements in centimeters of the digastric muscle on the left and right sides. (A) Anterior belly (AB); (B) intermediate tendon (IT); (C) posterior belly (PB) of the digastric muscle.

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  Fig. 4 Correlation of the length of anterior belly (AB) of digastric muscle with the distances between the bony landmarks in the region. (A) With the distance between symphysis menti and hyoid bone (Me-Hy) (r=–0.77), (B) with the distance between hyoid bone and mastoid process (Hy-Ma) (r=–0.26), (C) With the distance between symphysis menti and mastoid process (Me-Ma) (r=0.52).

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  Fig. 5 Correlation of the length of posterior belly (PB) of digastric muscle with the distances between the bony landmarks in the region. (A) With the distance between symphysis menti and hyoid bone (Me-Hy) (r=0.41), (B) with the distance between hyoid bone and mastoid process (Hy-Ma) (r=0.65), (C) With the distance between symphysis menti and mastoid process (Me-Ma) (r=0.21).

Reference

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