TRIANGLES OF NECK - ANATOMY - EASYMEDNOTES 2021


TRIANGLES OF NECK

There are 2 triangles of neck
1. Anterior triangle
2. Posterior triangle


ANTERIOR TRIANGLE OF THE NECK

  • The anterior triangle is present at the front of the neck.
  • On either side of the neck.

BOUNDARIES

  • Superior border: It is bounded by inferior border of mandible.
  • Medial border: It is bounded by the imaginary midline of neck .
  • Lateral border: It is bounded by anterior border of the sternocleidomastoid muscle.

CONTENTS

The contents of anterior triangle are muscles, nerves, arteries, veins and lymph nodes.
  1. Muscles: suprahyoid muscle- Superior, Infrahyoid muscle - Inferior
  2. Arteries: Common carotid artery
  3. Vein : Internal jugular vein
  4. Nerves: Facial nerve, Glossopharyngeal nerve, Vagus nerve, Accessory nerve, Hypoglossal nerve.

SUBDIVISIONS

The triangle is subdivide by hyoid bone, suprahyoid and infrahyoid muscles into four triangle.

CAROTID TRIANGLE

BORDER: 
The borders of the carotid triangle are:
  • Superior border : The superior border is bounded by posterior belly of the digastric muscle
  • Lateral border: The lateral border is bounded by medial border of the sternocleidomastoid muscle
  • Inferior border: The inferior border is bounded by superior belly of the omohyoid muscle.

CONTENTS: 
The contents of carotid triangle are:
  • Common carotid artery
  • internal jugular vein
  • hypoglossal and vagus nerve

SUBMENTAL TRIANGLE

The submental triangle is present underneath the chin and it contains submental lymph nodes.

BORDERS:
The borders of submental triangle are:

  • Inferior border: The inferior border is bounded by hyoid bone.
  • Medial border: The medial border is bounded by midline of the neck.
  • Lateral border: The lateral border is bounded by anterior belly of the digastric muscle.
And the floor of the submental triangle is formed by the mylohyoid muscle.

 
SUBMANDIBULAR TRIANGLE

Submandibular triangle is present underneath the body of the mandible and it contains submandibular gland.

BORDERS:
The boundaries of submandibular triangle are:
  • Superior border: The superior border is bounded by Body of the mandible.
  • Anterior border: The anterior border is bounded by Anterior belly of the digastric muscle.
  • Posterior border:  The posterior border is bounded by Posterior belly of digastric muscle.

 
MUSCULAR TRIANGLE

It has 4 boundaries, and it contains infrahyoid muscles,pharynx, thyroid, parathyroid glands.

BORDER:
  • Superior border: Hyoid bone.
  • Medial border: Imaginary midline.
  • Superolateral: Superior belly of the omohyoid muscle.
  • Inferolateral : Inferior portion of the sternocleidomastoid muscle.

POSTERIOR TRIANGLE OF THE NECK

The posterior triangle is located at the lateral side of the neck and it is an anatomical area.

BORDERS:

The boundaries of the posterior triangle is:

  • Anterior border: the posterior border of sternocleidomastoid muscle.
  • Posterior border: the anterior border of trapezius muscle.
  • Inferior border: meddle one third of the clavicle. The posterior triangle of neck is covered by a fascia.

CONTENTS

Muscles

Arteries

Veins

Nerves

MUSCLES

  • The posterior triangle consist of many muscle.

  • Omohyoid muscle- it has 2 bellies which is split by a tendon.

  • Inferior belly cross the posterior triangle by supero-medial direction which make the triangle split into two.

  • This muscle later crosses under the sternocleidomastoid muscle then enters into anterior triangle of the neck.


In the floor of the posterior triangle we can see 5 muscles: 

  • Splenius capitis
  • Levator scapulae
  • Anterior scalenes
  • Posterior scalenes
  • Middle scalenes

VASCULATURE

  • External jugular vein
  • Subclavian vein
  • Transverse cervical vein
  • Suprascapular vein
  • Subclavian artery

NERVES

  • Accessory nerve
  • Phrenic nerve


SUBDIVISION

The omohyoid muscle divides the triangle into 2 triangles they are:

Occipital triangle : Largest and it presents superiorly

Subclavian triangle: Presents inferior.



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