Neck

Suprahyoids

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Overview


The suprahyoid muscles are a collection of four paired muscles, situated superior to the hyoid bone. Their overall function is to elevate the hyoid and thus widen the oesophagus, aiding in mastication & swallowing.


Gross Anatomy


From superficial to deep: -

 

Stylohyoid

Origin

Styloid process

Insertion

Greater cornu of hyoid, superficial to digastric

Nerve

Facial nerve (CN VII) before it enters the parotid gland

Action

Elevates & retracts hyoid during swallowing


Digastric

Origin

 Ant. belly: digastric fossa on inner surface of mandible near midline

 Post. belly: base of mastoid

Insertion

Anterior and posterior bellies meet to form an intermediate tendon which passes through a fibrous loop anchored to the greater cornu of the hyoid

Nerve

  Ant. belly: Mylohyoid (branch of Mandibular division of Trigeminal nerve (CN Vc))

 Post. belly: Facial nerve (CN VII) before it enters the parotid gland

Action

Can either elevate hyoid or, if hyoid is fixed from below, depress mandible

 

 









Mylohyoid

Origin

Mylohyoid line along inner aspect of mandible

Insertion

Muscle on each side slopes down toward one other, the fibres from the anterior ¾ of each muscle interdigitating to form a midline raphe extending from chin to hyoid. The posterior ¼ of each muscle inserts onto the superior aspect of the hyoid body.

Action

A thin sheet-like muscle, mylohyoid forms the floor of the mouth. Supports & raises floor of mouth and elevates the hyoid.

Nerve

Mylohyoid (branch of Mandibular division of Trigeminal nerve (CN Vc))

 

Geniohyoid

Origin

Inferior mental spine (inner aspect of anterior mandible), deep to mylohyoid

Insertion

Upper border of the hyoid body, deep to mylohyoid

Action

Elevates & protracts hyoid or, if hyoid is fixed from below, depresses mandible

Nerve

C1 fibres travelling with Hypoglossal nerve (CN XII)



Clinical Anatomy


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Quick Anatomy


Key Facts

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Aide-Memoire

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Summary


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References


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