Thoracic Spine Anatomy and Pathology-Lecture

Question 1

Thoracic Inlet

Answer 1

• The thoracic inlet is the communication between the thoracic cavity and the root of the neck.
• Just to confuse you, “thoracic outlet syndrome” refers to the anatomic thoracic inlet rather than the outlet.

Question 2

Thoracic Outlet

Answer 2

• Anatomically, the thoracic outlet separates the thorax from the abdominal cavity.
• It is closed by the diaphragm.

Question 3

Thorax- Bones & Cartilage:

Answer 3

• The framework of the thoracic wall consists of the thoracic vertebrae, the ribs and their costal cartilages, and the sternum.
• There are 12 pairs of ribs
  
  • True ribs – 1 – 7: The costal cartilages of these ribs are attached to the sternum.
  • False ribs – 8 – 12: The costal cartilages of ribs 8-10 are attached to the costal cartilage of the rib above
  • Ribs 11 & 12 are “floating ribs” embedded in the musculature of the abdominal wall.

Question 4

Thoracic Wall- Thoracic Vertebrae:

Answer 4

• Bodies are medium sized and heart-shaped
• Vertebral foramen is small and generally round
• Have superior and inferior costal facets for articulation with the heads of the ribs
• Have costal facets on their transverse processes for articulation with the tubercles of the ribs (lacking on T11 and T12)
• Have long spinus processes which slant downwards
• The superior articular processes have facets that face posteriolaterally, while the inferior processes have facets that face anteriomedially. This allows for rotation.

Question 5

Thoracic wall- Ribs:

Answer 5

• The ribs are numbered 1 through 12 from top to bottom. They gradually increase, then decrease, in size.
• The heads of the ribs are posterior, where they articulate with the vertebra of the same number and with the superior vertebra.
• The bodies of the ribs are flattened from side to side.
• The ribs do not lie flat, but are twisted downwards.

Question 6

1st Rib

Answer 6

• shortest
• broadest
• most curved
• flattened from top to bottom
• superior surface has scalene tubercle for attachment of scalenus anterior, and grooves where the subclavian vessels cross.

Question 7

2nd Rib

Answer 7

• similar to first rib, but about twice as large
• does not have scalene tubercle or grooves
• looks like a giraffe

Question 8

10th, 11th, 12th rib

Answer 8

• only one facet for articulation with the vertebra

Question 9

Thoracic Wall- Costovertebral Joints:

Answer 9

Joints of the heads of the ribs:

• Ribs 2 - 10 articulate with two vertebrae and the intervening disc. These are plane type synovial joints.
• The more inferior costal facet articulates with the superior facet of the vertebra of the corresponding level
• The crest of the head of the rib is attached to the intervertebral disc above its level by an intra-articular ligament of the joint.
• The superior costal facet articulates with the inferior facet of the vertebra superior to it.
• Ribs 1, 11, and 12 (and sometimes 10) only articulate with the corresponding vertebrae

Costotransverse joints:

• The facet of the tubercle of the rib attaches to the transverse process of its corresponding vertebra.
• These are also plane type synovial joints.

Question 10

Thoracic Wall- Joints & Ligaments:

Answer 10

Ligaments of the vertebrae and ribs:

• Radiate ligament from the head of the rib to the 2 vertebrae and intervertebral disc
• Lateral and superior costotransverse ligaments between ribs and transverse processes

Question 11

Thoracic Wall- Sternum:

Answer 11

The sternum is made up of 3 bones joined by symphysis joints:

MANUBRIUM STERNI

• articulates with the clavicles, the 1st and 2nd ribs, and the body
• forms the jugular notch
• sternal angle (angle of Louis)
  
  • at the level of the T2 vertebra
  • 2nd rib articulation - ribs and intercostal spaces should always be determined starting at the sternal angle

BODY

• develops from 4 sternebrae, the edges of which may be visible
• is notched along the sides for the articulations with the costal cartilages

XIPHOID PROCESS- usually only partially ossified

Question 12

External Intercostal Muscles:

Answer 12

The external intercostal muscles run between adjacent ribs. Their fibers run in the direction of a person putting his hands in his pockets.

• Origin: lower border of the rib, from the tubercle of the rib posteriorly to the costal cartilage anteriorly. The gap from the end of the muscle to the sternum is filled in by the external intercostal membrane.
• Insertion: upper border of the rib below
• Innervation: intercostal nerves
• Action: the external intercostals work with the internal intercostals to pull the ribs closer together. If first rib is fixed (neck muscles), the intercostals raise the ribs; if the 12th rib is fixed (abdominal muscles), they pull the ribs down.

Question 13

Internal Intercostal Muscles:

Answer 13

The internal intercostal muscles are deep to the external intercostals. Their fibers run at right angles to the external fibers.

• Origin: subcostal groove of the rib, from the sternum anteriorly to the junction angle of the rib posteriorly. The gap from the end of the muscle to the vertebra is filled in by the internal intercostal membrane.
• Insertion: upper border of the rib below
• Innervation: intercostal nerves
• Action: the internal intercostals work with the external intercostals to pull the ribs closer together. If first rib is fixed (neck muscles), the intercostals raise the ribs; if the 12th rib is fixed (abdominal muscles), they pull the ribs down.

Question 14

Transversus thoracics:

Answer 14

• (innermost intercostal) is an incomplete layer that runs from the deep surface of the sternum to the adjacent ribs. It assists the intercostal muscles.

Question 15

Diaphragm:

Answer 15

The diaphragm has two domes or cupolae (singular = cupola).

It has three origins

• The sternal portion originates from the xiphoid process
• The costal portion originates from the lower 6 ribs and costal cartilages
• The vertebral portion consists of
  
  • crura from the bodies of the vertebrae and arcuate ligaments. The right crus is from the bodies and intervertebral discs of L1-L3. The left crus is from the bodies of L1 & L2 and the intervertebral disc
  • fibers from the arcuate ligaments: median arcuate ligament, medial arcuate ligament, & lateral arcuate ligament
• All fibers insert on the central tendon
• Innervation: phrenic nerve (C3, 4, and 5 keep the diaphragm alive)

Question 16

Thoracic Wall- Action of Respiratory Muscles:

Answer 16

• Mechanics of respiration: The lungs are highly elastic sacs suspended in the thoracic cavities and open to the air through the bronchi and trachea.
• An increase in the volume of the thoracic cavity against a closed glottis produces a negative pressure in the thoracic cavity.
• Opening of the glottis causes air to rush in through the trachea and expand the lungs.
• Quiet inspiration is achieved by increasing the volume of the thoracic cavities. Because of the shape of the ribs, elevating them anteriorly increases the anterior-posterior and lateral dimensions of the thoracic cavities (bucket handle effect). Contraction of the dome-shaped diaphragm increases the top to bottom dimension.
• Quiet expiration is a passive event due to the elasticity of the lungs themselves.
• On forced inspiration, all muscles which can elevate the ribs are used.

Question 17

Range of motion:

Answer 17

• The rib cage and sternum limits thoracic ROM
  
  • T1 – T12 – Total Range of Motion 36 degrees in sagittal plane
    
    • 16 degrees of flexion
    • 20 degrees of flexion
  • T1 – T12 – Total Range of Motion 44 degrees in frontal plane
    
    • 24 degrees of R side-bending
    • 20 degrees of L side-bending

Question 18

Coupled motion

Answer 18

• When spine is neither flexed nor extended
  
  • Side-bending and rotation are coupled in opposite directions

Question 19

Articulations:

Answer 19

• 12 separate articulations:
  
  • 4 zygapophyseal articulation
  • 2 costotransverse articulations
  • 4 costovertebral articulations
  • 2 body-IV disk-body articulations
  • Passive assessment of these articulations is difficulty and presents poor reliability

Question 20

CRLF Test:

Answer 20

1^st rib hypomobility in patients with brachialgia

• Cervical spine is rotated passively away for tested side
• The spine is flexed as far as possible
• Considered positive when lateral flexion movement is blocked

Question 21

Posture

Answer 21

• Poor upper quadrant posture has been implicated as a source of neck and shoulder pain.
• Patients with more severe postural abnormalities of the thoracic, cervical, and shoulder region have a significantly increased incidence of pain.
• Thoracic Kyphosis and rounded shoulders = cervical, interscapular, and headache pain.

Question 22

Thoracic spine and headaches

Answer 22

• Dysfunction of upper five thoracic spine segments is likely a PRIMARY generator of headaches
  
  • Therefore examination of the upper thorax spine in patients with headaches is warranted
  • Tx includes segmental mobilization and/or manipulation

Question 23

Movement and positional dysfunction

Answer 23

• The upper two segments of the thoracic spine often have restricted ability to extend fully
  
  • Flexed (kyphotic) posture
• The T3-T7 segment often have restricted ability to flex and concurrent external rib torsional dysfunction occurs
  
  • Flat back posture
  • T8-T12 segments often have a restricted ability to extend, resulting in a flexed
  • Flexed (kyphotic) posture

Question 24

Classification for thoracic and Rib Dysfunction:

Answer 24

• Mobilization – primary single segmental restriction of either flexion, extension, torsional rib cage dysfunction, and/or first rib restriction
• Immobilization – require motion restriction (hypermobility and instability)
  
  • Avoid movement stresses that promotes asymmetry
  • Muscle Activity to restore symmetry

Question 25

Thoracic spine and neck pain- Cleland and colleagues

Answer 25

• Cleland and colleagues….
  
  • Manipulation of the thoracic spine results in decreased neck pain in individuals with primary cervical complaints
  • Increases in cervical ROM after thoracic manipulation have been observed

Question 26

Osteoporosis and Thoracic Spine:

Answer 26

• Osteoporosis – loss of bone mass per unit of volume
  
  • Loss of bone in the axial skeleton predispose vertebral bodies to fracture
    
    • Results in back pain and deformity

Question 27

Thoracic osteoporosis- Symptoms

Answer 27

• Symptoms:
  
  • Midline back pain localized over the thoracic or lumbar spine
  • Treatment:
    
    • Exercise
    • Wbing activities

Question 28

Scheurmenn’s Disease

Answer 28

• Anterior wedging and vertebral end-plate irregularity in the thoracic spine
• Schmorl’s nodes
• AKA:
  
  • Juvenile Kyphosis
  • Vertebral Osteochondritis
  • Osteochondritis deformans juvenilis dorsi

Question 29

T4 syndrome- classification

Answer 29

• Classified as a group of symptoms including dysfunction within the T2-T7 segments
  
  • Pain in the upper limbs, neck, upper thoracic, and scapular region with cranial headaches
  • T4 is nearly always involved
  • Glove like paresthesia and numbness in one or both hands – nocturnal

Question 30

T4 syndrome- DDx

Answer 30

• Systemic illness
• Polyneuritis
• Nerve Root Compression

Question 31

T4 syndrome: Exam findings

Answer 31

• 4:1 ratio women to men
• Between 30 and 50 years
• Tenderness
• Asymmetry
• Limited Segmental ROM
• Tissue Thickening
• PA pressure
  
  • Over involved segment reproduces symptoms
• Spinal Mobilization and Manipulation are shown to be effective treatment techniques

Question 32

Metastatic lesions:

Answer 32

1. age >50 (sensitivity 77%, specificity 71%, +LR 2.7)
2. history of cancer (specificity 98%, +LR 15.5)
3. unexplained weight loss (specificity 94%, +LR 2.5)
4. failure of conservative therapy (specificity 90%, +LR 2.6)

Question 33

Post herpetic neuralgia

Answer 33

• Pain that persists for longer than 1 month after the rash of acute herpes zoster (resolves)
  
  • S/S
    
    • Burning or ache along a thoracic dermatome pattern
    • Involved skin area is often hypersensitive to light touch
    • Can mimic thoracic radiculopathy or referred pain of the thoracic spine origin

Question 34

Costochondritis

Answer 34

• Inflammation or irritation of the costochondral junction
  
  • Referred pain from thoracic or rib dysfunction
    
    • Likely the corresponding vertebra level
• Examination of the thoracic spine and posterior chest wall is warranted
• Treatment includes segmental mobilization and/or manipulation has been advocated

Question 35

Clinical pearls: Thoracic spine-Lower trap

Answer 35

• Pt demonstrates inhibition or difficulty in activing the lower trapezius muscle?
• Screen for T8 – T12 extension restrictions
• Mobilization/Manipulation my result in immediate improvement in lower trapezius muscle activation

Question 36

Clinical pearls- Thoracic spine: Serratus anterior

Answer 36

• Pt demonstrates inhibition of the serratus anterior muscle or has difficulty in stabilization the scapula during arm movements
• Screen T3-T7 for flexion restrictions
• Mobilization and manipulation has been shown to results in immediate improvements of serratus anterior.

Question 37

Cervical spine referral:

Answer 37

• C5-C6 & C5-C8
  
  • Commonly refer pain into the middle region of the back
  • NOTE:

Manual therapy procedures targeted at impairments of the cervical and thoracic spine result in decreased pain and improved function in patients with shoulder impingement syndrome