Prevertebral and Paravertebral Regions Anatomy

Prevertebral and Paravertebral Regions Anatomy Notes And Important Questions With Answers

Question 1: Where does trachea commence and terminate?

Answer: It begins at 6th cervical vertebra and ends at the plane which passes from angle of Illuis to lower

Question 2: What is tracheostomy and when is it done? What are the structures prone to injury? thoracic and vertebra. 

Answer:

1. A transverse incision made through the skin of the neck and anterior wall of the trachea is called tracheostomy.

2. Indications of tracheostomy

Body Fluids	Muscle Physiology	Digestive System
Endocrinology	Face Anatomy	Neck Anatomy
Lower Limb	Upper Limb	Nervous System

Read And Learn More: Face Anatomy Notes And Important Questions

1. Patients with extensive laryngeal damage,
2. Infants with severe airway obstruction,
3. For evacuation of excessive secretions,
4. For long continued artificial respiration.

3. Structures prone to injury

1. Isthmus of thyroid gland,
2. Inferior thyroid vein, and
3. Arteria thyroidea ima.

Question 3: Describe vertebral artery under the following heads:
1. Origin,
2. Branches and distribution,
3. Relations, and
4. Applied anatomy

Answer:

Vertebral Artery

1. Vertebral Artery Origin: It is the 1st branch of 1st part of subclavian artery.

It is the largst branch of subclavian artery.

It is one of the two principalsets of arteriesof th brain.

In addition, it also supplies spinal cord, meninges, surrounding muscles and bones.

2. Vertebral Artery  Branches and distribution: It is divided into four parts.

1. 1st part is cervical and is horizontal. It extends from the origin to entry into foramen transversarium.

2. 2nd part is vertebral and is vertical. It extends from 6th cervical vertebra to 1st cervical vertebra through foramen transversarium.
It gives Spinal, and Muscular branches.

3. 3rd part is suboccipital and is horizontal, arching over the atlas vertebra behind the superior articular facet.
It is present in the suboccipital triangle. It gives only muscular branches.

4. 4th part is cranial and is vertical.
It extends from posterior atlanto-occipital membrane to the lower border of pons.
It gives  Meningeal branches, which supply meninges of posterior cranial fossa.

1. Branches to brain and spinal cord.
2. Posterior spinal artery (branch ofvertebral artery) gives two branches which run anterior and posterior to dorsal root of spinal nerve.
3. Anterior spinal artery (branch of vertebral artery): It arises from terminal I part of vertebral artery and unites as it descends with the fellow of the opposite side to form anterior median trunk.
   It supplies medial part of medulla oblongata including pyramid and hypglossal nuclei.
4. Posterior inferior cerebellar artery: It is the most tortuous artery in the body.
   It is the largest branch of vertebral artery. It supplies

1. Lateral part of medulla,
2. 4th ventricle by forming choroid plexus,
3. Inferior vermis and inferolateral surface of cerebellar hemisphere,
4. Meningeal branch,and
5. Medullary branches.

3. Vertebral Artery  Relations

1. The sympathetic plexus of the vertebral artery runs around the artery.
2. Middle cervical ganglion lies anteromedially to vertebral artery.
3. Inferior cervical ganglion lies posteromedially to vertebral artery.

4. Vertebral Artery  Applied anatomy

1. Medial medullary syndrome: The lesion of the anterior spinal artery is manifested by

1. Impairment of volitional (desired) movement on the contralateral side due to involvement of corticospinal tract, and
2. Ipsilateral loss of movements of tongue,wasting of muscles of tongue.
   It is due to involvement of hypglossal nerve nucleus situated in the medulla.

2. Lateral medullary syndrome (Wallenberg’s syndrome): It is due to the lesion of posterior inferior cerebellar artery. This is manifested by

1. Loss of pain and thermal sensation of the same side of the face and opposite 1/2 of the body.
2. Paralysis of th vocal cords,soft palate and pharynl muscles of th same side.

Subclavian steal syndrome: It takes place in obstruction of the subclavian artery proximal to the origin of vertebral artery.
Some amount of blood is diverted

from the brain through the vertebral artery of the opposite side to maintain,collateral circulation.

Phrenic Nerve

1. Phrenic Nerve Origin: It is mainly formed from C4, with unimportant contribution from C3 and CS.
It is one of the most important nerves in the body, the principal motor supply to its own½ of diaphragm.
It also supplies peritoneum, pleura and pericardium.

2. Phrenic Nerve Course and relations

1. The nerve is formed at the lateral border of scalenus anterior, at the level of upper border of thyroid cartilage.
2. Phrenic Nerve runs vertically downwards on the anterior surface of scalenus anterior.

1. Phrenic Nerve lies behind subclavian vein and in front of subclavian artery.
2. The nerve lies deep to

1. Prevertebral fascia,
2. Inferior belly of omohyoid,
3. Transverse cervical artery,
4. Suprascapular artery, and
5. Internal jugular vein.

1. The nerve runs downward on the cervical pleura behind the commencement of brachiocephalic vein.
   It crosses the internal thoracic artery and enters the thorax.
2. In the thorax, the phrenic nerve descends in front of hilum of the lungs.
3. The right phrenic nerve is shorter and more vertical.

Note:

1. The Vagus nerve descends behind the hilum of the lung.
2. The right vagus nerve is shorter in length.

3. Phrenic Nerve Branches

1. Motor branches to diaphragm:

Phrenic nerve is main motor nerve to the diaphragm.

2. Sensory branches

1. Central part of diaphragm.
2. Pleura,
3. Pericardium, and
4. Peritoneum.

4. Phrenic Nerve Applied anatomy

1. The phrenic nerve may be injured by penetrating wounds of th neck or damaged.
   The damage is due to pressure of malignant tumours in the mediastinum.
2. If phrenic nerve is damaged, the corresponding 1/2 dome of the diaphragm will be paralyzed.
   The paralyzed 1/2 dome of the diaphragm will be relaxed and pushed up into the thorax by the positive abdominal pressure.
   As a result, the lower lobe of the lung on that side may collapse.
3. Phrenic avulsion is done to give rest to diaphragm. While dissecting phrenic nerve, one must keep in mind the possibility of accessory phrenic nerve in mind.
   If present, it might tear the subclavian vein with alarming symptoms. This is because the main trunk loops around the vessel.
   The accessory phrenic nerve, branch ofnerve to subclavius, is an important nerve of unimportant muscle.

Question 4: Describe atlantoaxial joints under the following heads:
1. Atlantoaxial Joints Articulating surface,
2. Atlantoaxial Joints Classification,
3. Atlantoaxial Joints Ligaments,
4. Atlantoaxial Joints Movements and muscles bringing movements, and
5. Atlantoaxial Joints Applied anatomy

Answer:

4. Movements and muscles producing movements: Movements at all three joints are rotatory movements and take place around a vertical axis.
The dens form a pivot around which the atlas rotates (carrying the skull with it). It is called the “NO” movement.

1. Ipsilateral: The muscles bring flexion of the neck on the same side. They are

1. Obliquus capitis inferior,
2. Rectus capitis posterior major and minor,
3. Longissimus capitis,
4. Spleniu capitis, and
5. Sternocleidomastoid of opposite side.

2. Contralateral: Sternocleidomastoid brings rotation of the neck on the opposite side.

5. Applied anatomy: Death by hanging may be due to

1. Rupture of the transverse ligament of atlas, or
2. Fracture of the dens of axis.
   As a result, the atlas is dislocated from the axis.
   The dens compresses the spinal cord and results in death.

Question 5: Describe atlantooccipital joints under the following heads:
1. Atlantooccipital Joints Classification,
2. Atlantooccipital Joints Ligaments,
3. Atlantooccipital Joints Movements and muscle-bringing movements, and
4. Atlantooccipital Joints Applied anatomy

Answer: 1.

Atlantooccipital Joints Classification

1. Structural: Biaxial, simple, ellipsoid variety of synovial joint. AB’S.

Axis: Biaxial

Depending upon number of bones simple since there are 2

1. articulating bones
2. Occipital condyle

Superior articular facet of atlas.

Shape: Ellipsoid

Atlantooccipital Joints Ligaments

1. Fibrous capsule

1. Attached to peripheral margin of articular surface.
2. It is thick posterolaterally, thin and loose anteromedially.

2. Synovial membrane: Internally, lines the fibrous capsule.

3. Anterior Atlanto-Occipital Membrane

1. It connects the anterior arch of atlas with the anterior margin of foramen magnum.
2. Laterally, it continues with the anterior part of capsular ligament.
3. Anteriorly, it is strengthened by the anterior longitudinal ligament.
4. It prevents excessive movements.

4. Posterior atlanto-occipital membrane

1. It extends from posterior margin of foramen magnum to the posterior arch of atlas.
2. Laterally, it continues as the posterior part of capsular ligament.

Movements And Muscles Bringing Movements:

Flexion and extension collectively called “YES” movement.

1. Flexion

Longus capitis

Rectus capitis anterior

Stemocleidomastoid

2. Extension

1. Rectus capitis posterior major
2. Rectus capitis posterior minor
3. Obliquus capitis
4. Semispinalis capitis
5. Splenius capitis
6. Longissimus capitis
7. Trapezius.

3. Lateral flexion

1. Stemomastoid (acting unilaterally).
2. Obliquus capitis.

4. Applied anatomy

1. The atlantoaxial region of the cervical spine can be visualized in transoral anteroposterior radiographs.
2. The transoral route is also utilized in surgical approaches to this region, with upward retraction of the soft palate and division of the posterior wall of the pharynx.