Sub mandibular triangle

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Lec. # 13

Tuesday 22-3-2011

Sub mandibular triangle

  • Mostly occupied by submandibular gland.

Superficial to the gland  facial vein.

Deep to the gland  facial artery.

  • Roof :

  1. skin 2- superficial fascia 3- platysma muscle

4-cervical branch of the facial nerve (which supplies the platysma)

5-investing deep fascia

  • note: the cervical deep fascia is divided into 3 parts : investing(outer) , pretracheal and prevertebral(inner).

  • Boundaries :

  • Anterior : by anterior belly of digastric muscle.

  • Posterior : by posterior belly of digastric muscle.

  • Superior : by the inferior border of the mandible.

  • Floor :

  • Consist of 3 muscles.

  • From anterior to posterior :

  1. Mylohioid 2- hyoglossus 3- middle constrictor of pharynx.

  • Contents :

1-Submandibular gland. 2- Submandibular duct. 3- Submandibular lymph nodes.

4-hypoglossal nerve. 5- mylohyoid nerve. 6- mylohyoid vessles.

7- facial artery & vein.

  • Submandibular gland :

  • General notes :

  • We have 3 glands: sublingual , submandibular & parotid gland.

  • The function of these glands is secretion.

  • All of them are originated from the mouth, so all of them open within the mouth.

  • Submandibular gland is in the middle between the sublingual & the parotid glands.

  • The submandibular gland is mixed gland ( mucus, serous)

  • Called seromucous because most of the secretion is serous.

  • It has 2 capsules : inner fibrous & outer investing fascia (like the parotid gland)

  • It is U shaped on its side, looping around the posterior border of mylohyoid  muscle.

  • The  mylohyoid  divides the mandibular gland into 2 parts :

  1. Large superficial part :

  • External to the mylohyoid muscle.

  • Inner to the mandible (to be more specific sub mandibular fossa).

  • External to it we have also facial vein & platysma.

  1. Smaller deep part :

  • Lies within the floor of the oral cavity.

  • Internal to mylohyoid.

  • External to hyoglossus.

It is sandwiched between mylohyoid and hyoglossus.

  • Inner to it also hypoglossal nerve & facial artery.

  • Gives the submandibular duct from anterior process.

  • Submandibular duct :

  • About 5 cm in length.

  • Extending from the anterior aspect of the deep partruns forward & upward between the  mylohyoid  & the hyoglossus muscle.

  • Pass below the floor of the mouth and open at the side of the frenulum of the tongue.

  • It has specific relations to the lingual nerve :

The lingual nerve loops (lateral, infiror and medial) around the submandibular duct.

  • Arterial supply of the submandibular gland : Facial artery & lingual artery

  • Venous drainage: facial & lingual vein.

  • Lymph drainage: submandibular lymph nodes that will send it back to the cervical lymph nodes.

(Mostly head and neck lymph nodes drain to the cervical lymph nodes).

  • Nerve supply :

  • Below the lingual nerve we have submandibular gangilion & it is Parasympathetic.

(All the ganglia in the head and neck are parasympathetic ganglions except for 6 cervical)

  • A submandibular ganglion gives the parasympathetic innervations to the submandibular gland.

  • Parasympathetic innervation is secretomotor.

  • Sympathetic innervation comes around arteries mostly.

  • The submandibular gland receives the sympathetic innervations from the facial artery.

  • The function of sympathetic innervations is to decrease the secretion.

  • NOTES:

  • The anterior belly of digastric & posterior belly of digastric is united in the intermediate tendon which will bind to the body of hyoid bone by facial stings.

  • Hypoglossal nerve :

1-Passes in two triangles: carotid & submandibular.

2-Sandwiched between the posterior belly of digastric & hyoglossus muscles.

  1. Sandwiched between mylohyoid & hyoglossus muscles

  • Facial artery is deep to the submandibular gland

DONE BY: Abdel-raheem yaseen.

Good luck for all of you in the mid terms :D

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