Tag: Suprahyoid muscles

Suprahyoid muscles

SUPRAHYOID MUSCLES


SUPRAHYOID MUSCLES

  • The suprahyoid muscles are four muscles located above the hyoid bone in the neck.
  • They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscles.
  • Anterior belly of digastric, Mylohyoid dervied from 1st branchial arch
  • Second branchial arch give rise to  stylohyoid, posterior belly of digastric muscles
  • They are all pharyngeal muscles, with the exception of the geniohyoid muscle.
  • The digastric is uniquely named for its two bellies eg Muscle fibers in the ligament of Treitz, Omohyoid, Occipitofrontalis

 

Muscle Origin Insertion Innervation
Digastric (anterior belly) Digastric fossa of Mandible Intermediate Tendon Mylohyoid nerve – branch of CN V3 (Mandibular division of Trigeminal nerve)
Digastric (posterior belly) Mastoid notch Intermediate Tendon Facial nerve
Geniohyoid Inferior mental spine of Symphysis menti Hyoid C1 via the hypoglossal nerve (XII)
Stylohyoid Temporal styloid process Hyoid Facial nerve
Mylohyoid Mylohyoid line of mandible Hyoid Mylohyoid nerve – branch of CN V3 (Mandibular division of Trigeminal nerve)

FUNCTIONS:

  • These four muscles have different actions, but in general assist in elevating the hyoid bone and widening the esophagus during swallowing.
  • Submandibular gland is divided into superficial and deep parts by mylohyoid.
  • When the two bellies of the digastric contract, they pull upward on the hyoid bone; but if the hyoid is fixed from below, the digastric assists in extreme opening of the mouth such as yawning or taking a large bite of an apple.
  • Stylohyoid & digastric are elevators of larynx.
  • The mylohyoid elevates the hyoid bone, tenses the floor of the mouth.
  • The Geniohyoid pulls the hyoid bone anterosuperiorly, shortening the floor of the mouth and widening the pharynx during swallowing.
  • The Stylohyoid elevates and retracts the hyoid bone, elongating the floor of the mouth during swallowing
Exam Question
 
  • Digastric muscles refers to muscles with two bellies are Muscle fibers in the ligament of Treitz, Omohyoid, Occipitofrontalis.
  • Posterior belly of digastric is supplied by Facial nerve.
  • Mylohyoid nerve – branch of CN V3 (Mandibular division of Trigeminal nerve) innervates anterior belly of trigeminal nerve.
  • Second branchial arch give rise to  stylohyoid, posterior belly of digastric muscles.
  • Stylohyoid & digastric are elevators of larynx.
  • Stylohyoid muscle is supplied by Facial nerve.
  • Submandibular gland is divided into superficial and deep parts by mylohyoid.
Don’t Forget to Solve all the previous Year Question asked on SUPRAHYOID MUSCLES

Suprahyoid muscles

SUPRAHYOID MUSCLES

Q. 1

Which of the following muscles is not supplied by mandibular nerve?

 A

Masseter

 B

Buccinator

 C

Tensor veli palati

 D

Posterior belly of digastric

Q. 1

Which of the following muscles is not supplied by mandibular nerve?

 A

Masseter

 B

Buccinator

 C

Tensor veli palati

 D

Posterior belly of digastric

Ans. D

Explanation:

Mandibular nerve supplies muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani and tensor veli palati. Nerve to the medial pterygoid is a small branch of mandibular nerve that supplies the medial pterygoid muscle. It gives off two branches which pass without interruption through the otic ganglion to supply tensor tympani and tensor veli palati.


Q. 2

Which of the following nerve innervates the anterior belly of the digastric muscle?

 A

Facial nerve

 B

Trigeminal nerve

 C

Vagus nerve

 D

Abducens nerve

Q. 2

Which of the following nerve innervates the anterior belly of the digastric muscle?

 A

Facial nerve

 B

Trigeminal nerve

 C

Vagus nerve

 D

Abducens nerve

Ans. B

Explanation:

The anterior belly of the digastric muscle is innervated by the mandibular division of the trigeminal nerve.

  • The inferior alveolar nerve which give rise to the mylohyoid nerve innervates the mylohyoid muscle. 

Q. 3

Second branchial arch give rise to all of the following muscles, EXCEPT:

 A

Stapedius

 B

Stylohyoid

 C

Stylopharyngeus

 D

Posterior belly of digastric

Q. 3

Second branchial arch give rise to all of the following muscles, EXCEPT:

 A

Stapedius

 B

Stylohyoid

 C

Stylopharyngeus

 D

Posterior belly of digastric

Ans. C

Explanation:

Second branchial arch give rise to muscles of facial expression, stylohyoid, posterior belly of digastric and stapedius. Third branchial arch give rise to stylopharyngeus muscle.
 
Muscles derived from first branchial are:
  • Masseter
  • Temporalis
  • Mylohyoid
  • Anterior belly of digastric
  • Tensor tympani
  • Tensor veli palatini
  • Lateral and medial pterygoid
Muscles derived from 4th branchial arch:
  • Inferior constrictor of pharynx
  • Cricothyroid
Muscles derived from 6th branchial arch:
  • All the intrinsic muscles of the larynx except cricothyroid
  • All the muscles of the pharynx except stylopharyngeus
  • All the muscles of palate except tensor palati

Q. 4

All of the following are Digastric muscles, Except:

 A

Muscle fibers in the ligament of Treitz

 B

Omohyoid

 C

Occipitofrontalis

 D

Sternocleidomastoid

Q. 4

All of the following are Digastric muscles, Except:

 A

Muscle fibers in the ligament of Treitz

 B

Omohyoid

 C

Occipitofrontalis

 D

Sternocleidomastoid

Ans. D

Explanation:

D i.e. Sternocleidomastoid

–   Diagastric, Omohyoid, Occipitofrontalis, Gastroenemius, and Suspensory muscle of duodenum (i.e., muscle in Ligament of Treitz)Q are all digastric muscles i.e, muscles with two muscle bellies. Mn- “DOGS”

Sternocleidomastoid muscle has two heads not two belliesQ


Q. 5

Posterior belly of digastric is supplied by‑

 A

Mandibular nerve

 B

Hypoglosal nerve

 C

Accessory nerve

 D

Facial nerve

Q. 5

Posterior belly of digastric is supplied by‑

 A

Mandibular nerve

 B

Hypoglosal nerve

 C

Accessory nerve

 D

Facial nerve

Ans. D

Explanation:

D i.e. Facial nerve


Q. 6

All are elevators of larynx except:

 A

Thyrohyoid

 B

Digastric

 C

Stylohyoid

 D

mylohyoid

Q. 6

All are elevators of larynx except:

 A

Thyrohyoid

 B

Digastric

 C

Stylohyoid

 D

mylohyoid

Ans. A

Explanation:

 

 The main laryngeal elevators are: Digastric anterior and posterior, the stylohyoid, mylohyoid, geniohyoid, genioglossus, hyoglossus, and thyropharyngeus muscles


Q. 7

Submandibular gland is divided into superficial and deep parts by ‑

 A

Digastric

 B

Geniohyoid

 C

Mylohyoid

 D

Stylohyoid

Q. 7

Submandibular gland is divided into superficial and deep parts by ‑

 A

Digastric

 B

Geniohyoid

 C

Mylohyoid

 D

Stylohyoid

Ans. C

Explanation:

Submandibular gland

  • This walnut sized gland lies below the mandible in the anterior part of digastric triangle. It is .1-shaped and consists of a large superficial and a small deep parts, separated by mylohyoid muscle and continuous with each other around the posterior border of mylohyoid muscle.

Superficial part

  • It is situated in the anterior part of digastric triangle. The gland is partially closed in a capsule formed by two layers of deep cervical fascia. It has three surfaces : (i) inferior, (ii) lateral, and (iii) medial.

i)    Inferior surface is covered by skin, platysma, cervical branch of facial nerve, deep fascia, facial vein and submandibular lymph nodes.

ii)   Lateral surface is related to submandibular fossa (on mandible), medial pterygoid (insertion) and facial artery.

iii)  Medial surface is related to mylohyoid, hyoglossus and styloglossus muscles.

Deep part

  • It lies on the hyoglossus muscle deep to mylohoid. It is related above to lingual nerve and submandibular ganglion; and below to hypoglossal nerve.

Q. 8

Posterior belly of digastric is supplied by

 A

Facial nerve

 B

Mandibular nerve

 C

Glossopharyndeal nerve

 D

Trochlear nerve

Q. 8

Posterior belly of digastric is supplied by

 A

Facial nerve

 B

Mandibular nerve

 C

Glossopharyndeal nerve

 D

Trochlear nerve

Ans. A

Explanation:

Ans. is `a’ i.e., Facial nerve


Q. 9

Which of the suprahyoid muscle is supplied muscle by both facial nerve & mandibular nerve?

 A

Stylohyoid

 B

Mylohyoid

 C

Digastric

 D

Hyoglossus

Q. 9

Which of the suprahyoid muscle is supplied muscle by both facial nerve & mandibular nerve?

 A

Stylohyoid

 B

Mylohyoid

 C

Digastric

 D

Hyoglossus

Ans. C

Explanation:

Anterior belly of digastric is supplied by nerve to mylohyoid (a branch of mandibular nerve) & posterior belly is supplied by facial nerve.


Q. 10

Muscle of neck with dual neerve supply?

 A

Sternohyoid

 B

Thyrohyoid

 C

Digastric

 D

Stylohyoid

Q. 10

Muscle of neck with dual neerve supply?

 A

Sternohyoid

 B

Thyrohyoid

 C

Digastric

 D

Stylohyoid

Ans. C

Explanation:

Anterior belly of digastric is supplied by nerve to mylohyoid (a branch of mandibular nerve) & posterior belly is supplied by facial nerve.


Q. 11

Oral diaphragm is formed by:

 A

Mylohyoid

 B

Geniohyoid

 C

Omohyoid

 D

Digastric

Q. 11

Oral diaphragm is formed by:

 A

Mylohyoid

 B

Geniohyoid

 C

Omohyoid

 D

Digastric

Ans. A

Explanation:

Mylohyoid muscle of each side unite to make a thin sheet of muscular floor (oral diaphragm) of oral cavity.


Q. 12

Structures lying deep to posterior belly of digastric are all except?

 A

Retromandibular vein

 B

Hypoglossal nerve

 C

Hyoglossus muscle

 D

Occipital artery

Q. 12

Structures lying deep to posterior belly of digastric are all except?

 A

Retromandibular vein

 B

Hypoglossal nerve

 C

Hyoglossus muscle

 D

Occipital artery

Ans. A

Explanation:

Relations of Digastric triangle

Superficial

Deep (medial)

  • Platysma
  • Mastoid process & sternocleidomastoid
  • Stykohyoid muscle
  • Retromandibular vein & parotid gland
  • Submandibular salivary gland
  • Angle of mandible with medial pterygoid

For anterior belly

  • Mylohyoid

For posterior belly

  • Transverse process of atlas with superior oblique & rectus capitis lateralis muscle.
  • Hyoglossus muscle
  • Hypoglossal & spinal accessory nerves
  • Occipital, internal & external carotid, facial & lingual arteries
  • Internal jugular vein

 



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