Thoracic Inlet I - OMM Lecture 38

*Difference between anatomic & functional thoracic inlet * (know for test)

*Anatomic*: - *Rib 1* (bilaterally) - *T1* - Superior end of manubrium *Functional:* - *Ribs 1-5* (bilaterally -* T1-5* - Manubrium - Sternum (gladiolus)

What nerves emerge between the anterior and middle scalene muscles superior to the first rib & pass obliquely and inferiorly underneath the clavicle, into the shoulder, & down the arm?

*Brachial plexus*

The thoracic cavity is lined by what?

*Endothoracic fascia* - Lies between the deep muscle of the chest wall & the costal portion of the parietal pleura (to which it is firmly attached). - Ultimately covers the intercostal muscles all the way to the diaphragm, lies between the parietal pleura and the thoracic cage, & lies over the bodies of the vertebra and their discs

T/F: The clinical entity called *Thoracic Outlet Syndrome* refers to the inferior thoracic aperture.

*False* - refers to the superior thoracic aperture, b/c the anatomic thoracic inlet is clinically referred to as the thoracic outlet.

The endothoracic fascia partially or completely surrounds what structures?

- Azygous & hemiazygous veins - *Thoracic duct* - Sympathetic chain - Splanchnic (pre-ganglionic sympathetic) nerves

Defintion/what's included in the *functional* thoracic inlet

- First 5 thoracic vertebrae - First 5 ribs & their costocartilages - Manubrium - Sternum (gladiolus)

*If the diagnosis for thoracic inlet is sidebent & rotated right, what way will the sternum point?* What side would you have resistance to skin drag?

- Sternum points* left* - Harder to drag to the left -- ease of motion to the right

Landmarks you use to diagnose SDs of the thoracic inlet

- T1 - 1st rib

Osteopathically speaking, to *fully treat* the thoracic inlet, we need to diagnose and treat what?

- T1-5 - Ribs 1-5

Structures that course through the thoracic inlet

- Trachea - Esophagus - Nerves (Phrenic, Vagus, Recurrent laryngeal, Sympathetic trunks) - Arteries (Common carotid, Brachiocephalic trunk, Subclavian) - Veins (Internal jugular, Brachiocephalic, Subclavian) - Lymph nodes & lymphatic vessels

How to set up & treat for thoracic inlet rotation

1. Rotate head away 2. Place index finger behind the costotransverse articulation on the side of the rotated first rib, & place firm pressure in an inferior (toward patient's feet) & rotationaldirection 3. Scoop head back 4. May need to slightly flex or extend, rotate or sidebend to localize the barrier 5. Patient's nose should remain in midline *ME* - have pt push against hand lying against their chin

How to set up & treat for thoracic inlet sidebending

1. Rotate head away from side of high rib 2. Place index finger lateral & superior to costotransverse articulation on the side of the high first rib, & place firm pressure in an inferior (toward patient's feet) & medial direction 3. Scoop head back 4. May need to slightly flex or extend, rotate or sidebend to localize the barrier 5. Patient's nose should remain in midline *ME* - have pt push head into hand that's beneath their head (pushing into the table)

If the thoracic inlet is acting as a unit and the first rib is sidebent and rotated right, what would that mean for the first thoracic vertebra?

Also sidebent & rotated right

Whenever possible, treatment of the thoracic inlet should begin with what?

Balancing of the upper thoracic cavity (first 5 thoracic vertebrae & first 5 ribs)

*Why is the thoracic inlet of importance in lymphatic drainage?*

Because the lymphatic system for the whole body drains into the venous system immediately posterior to the medial end of the clavicle & 1st rib

Impingement of what in the region of the scalenes, ribs, & clavicles is responsible for neurogenic thoracic outlet syndrome?

Brachial plexus

*Functionally, Sibson's fascia may act as what?*

Cervicothoracic diaphragm

Inferiorly, the endothoracic fascia thins considerably over the superior surface of the diaphragm, but is continuous with ___________ after it passes through the aortic hiatus.

Inferiorly, the endothoracic fascia thins considerably over the superior surface of the diaphragm, but is continuous with the *internal investing fascia of the abdominal cavity* after it passes through the aortic hiatus.

How to diagnose rotation of the thoracic inlet

Place your fingers in the *costoclavicular space* (roll your fingers over the top of the medial end of the clavicle) and press into the chest (down into the table, NOT towards the patient's feet)

With the exception of the first fib, what type of joints are the sternocostal articulations?

Plane or gliding joints w/ synovial cavities

How to diagnose sidebending of the thoracic inlet

Press down on the 1st rib, moving it towards the feet

*CCP pattern for the thoracic inlet*

Rotated & sidebent *right*

What structure covers the cupola of the lung & is the innermost lining of the scalene muscles?

Sibson's fascia

What structure starts between the transverse process of C7 and the front of the internal border of the 1st rib and is continuous with the deep cervical fascia?

Sibson's fascia

Definition of *anatomic* thoracic inlet (TI)

Superior opening of the thoracic cavity - First ribs bilaterally - First thoracic vertebra - Superior end of manubrium - May be reffered to as the operculum (lid) as they all have a tendency to act as a unit

Superiorly, the endothoracic fascia extends over the apices of the lungs, where it thickens and forms what?

Suprapleural membrana -- aka *Sibson's fascia*

Viscero-somatic levels for the sensory organs of the head

Sympathetic control is T1-4 & the cervical sympathetic plexus

Viscero-somatic levels for the thyroid

T1-4 BL

Viscero-somatic levels for the heart

T1-5 left

Viscero-somatic levels for the lung & visceral pleura

T1-6 BL

Viscero-somatic levels for the arms

T2-8 BL

Viscero-somatic levels for the pancreas

T5-11

Viscero-somatic levels for the stomach

T5-9 left

The superior thoracic aperture is known *anatomically* as the thoracic ____________(inlet/outlet) and *clinically* as the thoracic ___________(inlet/outlet).

The superior thoracic aperture is known *anatomically* as the thoracic *inlet* and *clinically* as the thoracic *outlet*.

Def - Ring formed by T1, the first rib on each side, and the manubrium.

Thoracic inlet (anatomic definition)

T/F: A thoracic cage & vertebral column free of somatic dysfunctions will result in thoracic symmetry & freedom of motion, which are required for optimal functioning of the thoracic contents (and ultimately the rest of the body).

True

T/F: Altered rib cage function influences respiratory activity, circulatory activity (Arterial, venous, & lymphatic), and neural activity (particularly of the intercostal nerves & the brachial plexus superior to the first rib).

True

T/F: Osteopathetic theory states that treatment of the thoracic inlet may have *one of the most important* positive effects on the venous & lymphatic drainage of the whole body.

True

T/F: The optimal function of the thoracic inlet gained by OMM included the continual effective negative intrathoracic pressure, which improves the terminal lymphatic drainage, which is *essential for maintaining homeostasis*.

True

T/F: The ring formed by T1, the first rib on each side, and the manubrium acts as a unit because of the single costovertebral articulation, costotransverse articulation, and the synchondrosis of the cartilage between the first rib and the manubrium.

True

The costal cartilage of the first rib is *directly united* with the sternum to form what type of joint?

Typical *synchondrosis* (an almost immovable joint between bones bound by a layer of cartilage, as in the vertebrae)

When is the thoracic inlet considered to be acting as a unit?

When it's rotated & sidebent to the same side