Cervical spine mechanics and thoracic spine Flashcards
Understand the significance of facet orientation
Cervical spine:
– Overall, the csp has the greatest range of movement, across the whole spine
– OA joint; is all about flexion/extension
– C1,2 is all about rotation
– C3,4 has the greatest ROM for the whole cervical spine
Facet orientation:
– 45 degrees coronal-
—- facilitates flexion and extension, reducing simple rotation and sidebending
—- capsules are lax to allow sufficient movement
—- C5-C6 (most), C4-C5, C6-C7 all have more movement, this can put it more at risk of degeneration and osteophyte formation
Thoracic spine:
– 60 degrees coronal facet orientation- again allows for
—- again facilitating flexion and extension while reducing rotation and sidebending
T1, T11 and T12 all classed as transitional as their facets are similar to those of CSP (T1) and lumbar spine (T11 and T12)
– generally has the least range of movement compared to the rest of the spine
—- provides an anchor to the csp to complete its roll
—- also allows for a stable structure from which the ribs can articulate with involuntarily
Roll and slide
Occipital Atlanto
Convex on concave, they move in the opposite direction
Convex- occipital facet
Concave- atlas facet
The occipital facet will roll atlas facet will slide
Head flexion:
– occipital facet rolls superiorly
– atlas facet slides posteriorly
Head extension:
– occipital facet rolls posteriorly
– atlas facet slides anteriorly
Occipital is the active mover and atlas is passive
Lever
Cervical spine:
– 1st class lever:
—- effort, fulcrum, load
— effort coming from the neck muscles to move the load of the head (any muscles that produces flexion, extension, SB and rotation)
Types of forces affecting the cervical spine
There are a number of forces that can affect the cervical spine:
– tension
– compression (where the cervical spine is being compressed from below and above)
– bending
– shear
– torsion (twisting force)
– combined loading
Neuroanatomy
Neurological points of vulnerability within the cervical spine:
– the intervertebral foramen:
—- where the nerve root exits
—- its covered in fascia, so any problems that cause inflammation can cause a problem
—- its close to the facets, so degeneration and formation of osteophytes from facet dysfunction or spondylitic changes can cause nerve problems like nerve compression
—- disc herniation can cause nerve root problems:
——- discs usually prolapse posterolaterally meaning there is an increased likelihood that a disc will cause a nerve root problem
—- central disc prolapse can cause a myelopathy pressing up against the spinal cord
Breathing mechanics and how COPD can affect it
Ribs act as a bellows:
– this is able to happen as there is a closed sealed system made by where:
—- you have the lungs (pleural tissue), you have the pleural membrane that surrounds the lungs
—- and then the lining ff the whole thorax is called Sibson’s fascia (protects the apex of the lung)
— this all allows the ribs to change in volume and allow them to act as a bellows for breathing
Ribs 1-7- pump handle
Ribs 8-10- bucket handle
Ribs 11-12- calliper
Inspiration:
– lungs inflate, diaphragm contracts and pulls down, the muscles of the ribs pull the ribs up opening and increasing the thoracic space, decreasing space inside to allow air in
Expiration:
– lungs exhale and deflate, the diaphragm relaxes and the thoracic space decreases in size, increasing pressure compared to atmospheric forcing air out into the atmosphere
Breathing mechanics:
– birth–>6 weeks- 30-40 breaths per min
– 6 months- 25-40 breaths per min
– 3 years- 20-30 breaths
– 6 years- 18-25
– 10 years- 17-23
Adults- 12-18
– elderly >65- 12-18
– elderly >80- 10-30
How COPD can affect this:
– COPD can cause hyperinflation of the lungs leading to reduced chest expansion during breathing
– COPD can cause respiratory muscle weakness and respiratory muscle endurance problems, this can lead to decreased chest expansion during breathing
How hyperinflated lungs can affect breathing mechanics:
– hyper inflated lungs can be caused by COPD
– The presence of lung overinflation limits the ability of tidal volume to expand, and ventilation can only be increased by faster breathing, contributing to further hyperinflation in a vicious cycle.
Impact working posture has on breathing mechanics
Forward head posture:
– can affect breathing mechanics
– result in an expansion of the upper thorax and contraction of the lower thorax. These changes can decrease the respiratory function.
Kyphotic posture:
– an example is schuermans posture (excessive thoracic kyphosis)
– results in reduced rib excursion so reduced rib expansion.
– there may be increased intra-abdominal pressure, which affects diaphragmatic movement:
– reduced lung capacity
– reduced inspiratory flow
– decreased forced vital capacity
Slouched or hunched position:
– Sitting or standing in a slouched or hunched posture can compress the chest and restrict the movement of the diaphragm.
– this can limit the ability of the lungs to expand fully during inhalation and reduce the efficiency of breathing.
– may lead to shallow breathing, where the upper chest is involved rather than the full capacity of the lungs
Limiting factors to breathing
Working posture
COPD
Age- advanced age leads to increased muscle stiffness which leads to reduced compliance
Scoliosis- can lead to excessive side bend and rotation affecting the thoracic compliance and rib extension
Schierman’s kyphosis- leads to excessive thoracic kyphosis, resulting in reduced rib excursion and thoracic expansion
RA- leads to increased stiffness and inflammation of the cartilage of sternocostal joints, resulting in rib excursion
Obesity
Diaphragm
Innervation:
– C3,4 and 5 (phrenic nerve)
Anatomical position and attachments:
- There are peripheral and central attachments:
3 peripheral attachments:
– lumbar vertebrae and arcuate ligaments
– costal cartilages of ribs 7-10 (attach directly to ribs 11 and 12)
– xiphoid process of the sternum
Left and right crus-
RC- L1-L3 and their intervertebral discs
LC- L1-L2 and their intervertebral discs
The muscle fibres of the diaphragm combine to form a central tendon. This tendon ascends to fuse with the inferior surface of the fibrous pericardium
– so if someone is complaining of low back pain, always ask them if they have recently had a cough or a cold
because someone who has had a cold or a UTI can put strain through the left and right crus
– attachment of left and right crus on the anterior vertebral bodies of T12-L3/4
– proximal attachments of the QL are the lower ribs 10,11,12 and then onto the iliac crest
– both muscles are key respiratory muscles and can be strained during the expulsion of coughing
– central tendon goes from diaphragm to the pericardium
