TRIANGLES OF NECK

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Q.1 Name the structures palpable anteriorly in the midline of the neck.

• Body of hyoid bone
• Adam’s apple (Thyroid cartilage)
• Arch of cricoid cartilage
• Tracheal ring
• Isthmus of thyroid gland.
• Suprasternal notch
  
  

Q.2 What is Platysma?

It is a subcutaneous muscle forming a thin fleshy sheath running upwards and medially on the neck from deltoid and pectoral fasciae to the base of mandible. It is supplied by the cervical branch of the facial nerve.

Functions:

• Helps in releasing pressure of the skin on superficial veins.
• Pulls the angle of mouth downwards.
  
  

Q.3 What is ‘jugular arch’?

A transverse channel in the suprasternal space connecting the two anterior jugular veins.

Q.4 What is the position of ‘subhyoid bursa’? What is its function?

Position:
Between the posterior surface of body hyoid bone and thyrohyoid membrane.

Function:
Lessens friction between the above two structures during swallowing.

Q.5 What are the boundaries of the ‘anterior triangular’ of the neck?

Anterior: Anterior median line of neck.

Posterior: Anterior border of sternomastoid.

Base: Base of the mandible and a line joining angle of the mandible to the mastoid process.

Apex: Manubrium sterni.

Q.6 What are the subdivisions of the anterior triangle?

• Submental,
• Digastric,
• Carotid and
• Muscular triangle.
  
  

Q.7 What are the areas drained by submental lymph nodes?

• Superficial tissues below the chin
• Central part of the lower lip and the adjoining gum.
• Anterior part of the floor of mouth
• Tip of tongue.
  
  

Q.8 What are the areas drained by submandibular lymph nodes?

• Centre of forehead
• Nose with frontal, maxillary and ethmoidal air sinuses
• Inner canthus of eye
• Upper lip and anterior part of the cheek with underlying gum and teeth
• Outer part of the lower lip with lower gum and teeth
• Anterior 2/3 of tongue (excluding tip)
• Floor of mouth.
• Efferents from submental nodes.
  
  

Q.9 What are the boundaries of the digastric triangle?

Anteroinferiorly: Anterior belly of digastric

Posteroinferiorly: Posterior belly of digastric Stylohyoid

Base: Base of the mandible and a line joining angle of the mandible to the mastoid process

Roof: Skin Superficial fascia: Has platysma and cervical branch of facial nerve Deep fascia: Splits to enclose submandibular gland

Floor: Mylohyoid, Hyoglossus, and middle constrictor muscle.

Q.10 Name the various structures lying over hyoglossus muscle.

• Lingual nerve
• Submandibular ganglion
• Submandibular duct
• Mylohyoid nerve
• Hypoglossal nerve
• Stylohyoid muscle
  
  

Q.11 Name the various structures passing deep to hyoglossus muscle.

• Glossopharyngeal nerve
• Stylohyoid ligament
• Lingual artery
  
  

Q.12 Name the structures passing between external and internal carotid arteries.

• Styloglossus.
• Stylopharyngeus.
• Glossopharyngeal nerve.
• Pharyngeal branch of the vagus nerve.
• Styloid process
• Part of the parotid gland.
  
  

Q.13 What are the boundaries of the carotid triangle?

Superiorly: Posterior belly of digastric, Stylohyoid

Anteroinferiorly: Superior belly of omohyoid

Posteriorly: Anterior border of sternomastoid

Roof: Skin Superficial fascia having platysma, cervical branch of the facial nerve and transverse cutaneous nerve of neck Investing layer of deep fascia

Floor: Thyrohyoid, Hyoglossus, Middle constrictor, and Inferior constrictor.

Q.14 Name the contents of the carotid triangle.

   • Arteries:
   Common carotid, Internal carotid, and External carotid and its branches.

   • Veins:
   Internal jugular, Common facial, Pharyngeal, Lingual and Superior thyroid.

  • Nerves:
   Vagus, Superior laryngeal, Hypoglossal and Sympathetic chain.

  • Carotid sheath with its contents

  • Deep cervical lymph nodes.

Q.15 What is the position, structure, and function of carotid sinus?

Position:
At the termination of the common carotid artery as slight dilatation.

Characteristics:
  Media thin,
  Adventitia thick,
Rich innervation by plexus formed by glossopharyngeal (mainly), sympathetic and vagus nerve.

Function:
As a baroreceptor helps to regulate blood pressure.

Q.16 What is the position, structure, and function of carotid bodies?

Position:
Present at the bifurcation of the common carotid artery near carotid sinus.

Structure:
  Has characteristic glomus cells, similar to neurons.
Also has sympathetic and parasympathetic postganglionic neurons and afferent nerve terminals from the glossopharyngeal nerve.

Function:
Act as chemoreceptors to monitor oxygen and carbon dioxide levels in the blood by reflexly controlling the rate and depth of respiration.

Q.17 What are the branches of the external carotid artery?

Anteriorly:
Superior thyroid, Lingual and Facial.

Posteriorly:
Occipital and Posterior auricular.

Medial: Ascending pharyngeal.

Terminal:
Maxillary and Superficial temporal.

Q.18 Name the infrahyoid muscles.

• Sternohyoid,
• Sternothyroid,
• Thyrohyoid and
• Omohyoid
  
  

Q.19 Name the suprahyoid muscles.

• Mylohyoid,
• Digastric,
• Stylohyoid and
• Geniohyoid.
  
  

Q.20 What is the nerve supply of digastric muscle?

Anterior belly by mylohyoid branch of inferior alveolar nerve (V nerve) and posterior belly by the facial nerve.

Q.21 What are the attachments of omohyoid muscle?

 It has two bellies:

• Inferior belly:
  Origin from the upper border of scapula near scapular notch and ends deep to sternocleidomastoid by joining intermediate tendon.
  
  
• Superior belly:
  From intermediate tendon to lower border of body of hyoid bone.
  
  

Q.22 What are the boundaries submental triangle?

Base is formed by hyoid bone. Above and laterally on each side by the anterior belly of the digastric muscle. Floor by mylohyoid muscle. So half of it lies on each side of the midline of the neck.

Q.23 What are the boundaries of the muscular triangle?

Posterorinferiorly: Sternocleidomastoid muscle

Posterosuperiorly: Superior belly of omohyoid

Anteriorly: Anterior midline of neck.

Q.24 What are the contents of the muscular triangle?

• Infrahyoid muscle
• Thyroid gland
• Larynx and trachea
• Carotid sheath and its contents
• Brachiocephalic artery
  
  

Q.25 What are the boundaries of suboccipital trinagle?

Superomedially:
Rectus capitis posterior major, Rectus capitis posterior minor

Superolaterally:
Obliquus capitis superior

Inferiorly: Obliquus capitis inferior.

Roof:
Medially: Fibrous tissue
Laterally: Longissimus capitis

Floor:
Posterior arch of atlas
Posterior atlanto-occipital membrane.

Q.26 What are the contents of the sub-occipital triangle?

• Third part of vertebral artery
• Dorsal ramus of C1
• Suboccipital plexus of veins
• Greater occipital nerve.
  
  

Q.27 What are the contents of ‘Suprasternal space of Burns’?

• Sternal head of sternomastoid,
• Jugular venous arch,
• Interclavicular ligament and
• Lymph node.
  
  

Q.28 What are the structures traversing supraclavicular space?

• External jugular vein,
• Supraclavicular nerves,
• Cutaneous vessels and,
• Lymphatics.
  
  

Q.29 What are the contents of the carotid sheath?

• Common carotid artery,
• Internal carotid artery,
• Internal jugular vein and
• Vagus nerve.
  
  

Q.30 Why the infections behind the prevertebral fascia do not extend to the posterior mediastinum?

Because the prevertebral fascia is attached to the fourth thoracic vertebra, which limits the downward spread of infection.

Q.31 What are the boundaries of the posterior triangle?

Anterior: Posterior border of sternomastoid.

Posterior: Anterior border of trapezius.

Base: Middle 1/3 of clavicle.

Apex: Point where trapezius and sternomastoid meet.

Roof: Investing layer of deep cervical fascia.

Floor: Prevertebral layer of deep cervical fascia covering the muscles.

 

Q.32 What are the structures present in the floor of the posterior triangle below deep cervical fascia?

Semispinalis capitis,
Splenius capitis
Levator scapulae,
Scalenus posterior,
Scalenus medius, and
Scalenus anterior.

By inferior belly of omohyoid in lower part, it is divided into the upper part (occipital triangle) and lower part (supraclavicular triangle)

Q.33 What are the contents of the posterior triangle of the neck?

• Cutaneous branches of cervical plexus:
  – Supraclavicular
  – Lesser occipital
  – Greater auricular
  – Transverse cutaneous

• Muscular branches from cervical plexus:
  – Levator scapulae
  – Trapezius

• Spinal accessory nerve
• Trunks of brachial plexus
• Branches of brachial plexus:
  – Nerve to rhomboids
  – Nerve to serratus anterior
  – Nerve to subclavius
  – Suprascapular nerve

• Subclavian artery
• Transverse cervical artery
• Occipital artery.

Q.34 What are ‘Signal nodes’?

These are lymph nodes that are enlarged in the malignant growths of distant places e.g., left supraclavicular nodes in malignancy of stomach, testes, and other abdominal organs.

Q.35 What is the origin of sternomastoid?

• Sternal head: From superolateral part of front of manubrium sterni .
• Clavicular head: Medial 1/3 of the superior surface of the clavicle.
  
  

Q.36 What is the nerve supply of sternomastoid?

Motor:
Spinal accessory nerve.

Sensory:
Ventral rami of C2,3.

Q.37 What is the action of sternocleidomastoid muscle?

When muscle of one side contacts, the head is tilted to the same side, and the face is rotated to the opposite side. When muscles of both sides act together, the head and neck are flexed.

Q.38 What is ‘torticollis’?

 Also known as Wryneck. The head is bent to one side and chin points to the other side.

Q.39 How torticollis occurs?

It occurs due to the spasm of muscles supplied by spinal accessory nerve i.e., sternomastoid and trapezius.