Anatomy - Thorax Osteology and Arthrology

The trunk is comprised of how many vertebrae?

33

What is the function of the thorax?

- To facilitate breathing

- Protection of vital organs

- Conduit for structures that pass through

What are the contents of the posterior components of the thorax?

12 thoracic vertebrae and their intervening intervertebral discs

What are the contents of the lateral thorax?

- ribs (12 on each side)

- three layers of flat muscles

What is the function of the flat muscles of the lateral thorax?

- Span the intercostal spaces between adjacent ribs

- Move the ribs

- Provide support for the intercostal space

What are the contents of the anterior thorax?

- Manubrium of sternum

- Body of sternum

- Xiphoid process

Each thoracic vertebrae articulates with

A rib

The function of the sternum is to

Protect mediastinal viscera, specifically the heart

The sternum is comprised of

- Manubrium

- Body

- Xiphoid process

The manubrium of the sternum lies at the level of

T3-T5

The body of the sternum lies at the level of

T5-T9

The xiphoid process of the sternum lies at the level of

T9-T10

The clavicular notch is an articulation point between the

Clavicle and manubrium

The surfaces of the clavicular notch are what shape?

Concave

The 1st costal notch is an articulation point between the

1st rib and manubrium

At the 1st costal notch, what type of joint is formed?

A synchondrosis joint with the costal cartilage of the 1st rib

The sternal angle of the manubrium is

A junction between the manubrium and the sternal body

The sternal body articulates with

Ribs 2-7

In children, the xiphoid process is

Cartilaginous and ossifies with age

The xiphoid process landmark for

- Superior limit of the liver

- Diaphragm

- Inferior border of the heart

A true rib directly articulates

To the sternum via costal cartilage

A false rib is

A rib that indirectly attaches to the sternum by attaching to the costal cartilage above

The true ribs are ribs _ to _

1-7

The false ribs are ribs _ to _

8-12

The floating ribs have

No attachment to the sternum

A typical rib consists of

- Head

- Neck

- Tubercle

- Body

- Angle

- Costal groove

The head of a typical rib contains

2 facets that articulate with corresponding vertebra and the superior vertebra

The neck of a typical rib connects the

Head to the body

The tubercle of a typical rib contains

A facet to articulate with the transverse process of the corresponding vertebra

The angle of a typical rib is an area where

The rib turns more anterolateral

The costal groove of a typical rib is

A concave internal surface of the body of the rib

The atypical ribs includes ribs

1st ,2nd ,10th-12th

What are the distinct landmarks of the first rib?

- single facet on head of rib to connect to T1

- Grooves for subclavian artery/vein

- Scalene tubercle

What are the distinct landmarks of the 2nd rib?

- Two facets on the head of the rib to connect to T1 and T2

- Tuberosity for serratus anterior

What are the distinct landmarks for ribs 10-12?

Single facet on head of rib to connect to their corresponding vertebrae (only connects to one vertebra)

What are the functions of the costal cartilages?

- Prolongs ribs anteriorly to connect to sternum

- Allows for elasticity of thoracic wall

The costochondral joint is formed between the

End of ribs and lateral end of costal cartilage

The sternocostal joint of the 1st rib is formed between the

1st costal cartilage and manubrium

The sternocostal joint of the 2nd - 7th ribs is formed between the

2nd-7th costal cartilages and the sternum

The sternocostal joints are reinforced by the

Anterior and posterior sternocostal radiate ligaments

During inhalation the upper ribs (1-7) and sternum move in the

Sagittal plane in a superior-anterior direction, and the sternum moves like a pump handle

During inhalation, the lower ribs move in

The frontal plane in a superior-lateral direction, and the ribs move like a bucket handle

What are the boundaries of the superior thoracic aperature

- T1 vertebra

- Left and right 1st ribs

- Manubrium

What are the contents of the superior thoracic aperture?

- Trachea

- Esophagus

- Blood vessels of the head and upper limb

- Sympathetic nerves

- Phrenic nerve (to diaphragm)

- Vagus nerve (to organs)

The are the boundaries of the inferior thoracic aperture?

- T12 vertebra

- Left and right 11th and 12th ribs

- Costal cartilages of ribs 7-10

- Xiphisternal joint

Inferior thoracic aperture

Superior thoracic aperture

What is the function of the spine?

- Protects spinal cord

- Supports weight of body above the pelvis

- Provides rigid base for head to function, as well as flexible axis for body to move

- Plays an important role in posture and locomotion

Of the 33 vertebrae, significant motion primarily occurs between the

Superior 25 vertebrae

The sacrum is formed by the

Fusing of the 5 sacral vertebrae

The coccyx is formed by the

Fusing of the 4 coccygeal vertebrae at around age 30

In lordosis the spine is

Concave posteriorly

In kyphosis, the spine is

Concave anteriorly

Cervical lordosis develops during

Infancy, when the child learns to extend head and look up while prone

Cervical kyphosis develops during

Fetal period when fetus is in flexed position

Lumbar lordosis is developed

Around 1 year of age, when child learns to stand

What is the function of the intervertebral discs?

- Permits movements between adjacent vertebrae

- Absorb shock during weight bearing activities

- Contributes to full length of vertebral column

The intervertebral disc is comprised of the

- Anulus fibrosis

- Nucleus pulposus

The anulus fibrosis is a

Concentric ring of fibrocartilage around the perimeter of the IV discs

The anulus fibrosis inserts onto the

Outer rim of vertebral bodies

The anulus fibrosis is thinner on the _ side compared to the _

Posterior; anterior

The nucleus pulposis allows for

Flexibility and load bearing of disc

The nucleus pulposis is the _ of the IV disc and is made up of

Core; 80% water

The intervertebral joint is an articulation between the

Vertebral bodies and intervertebral discs

A typical vertebrae consists of

- A vertebral body

- A vertebral arch

- 7 processes

The vertebra body is an _ structure that gives

Anterior; support to the spinal column

Why does the vertebra body get larger in size as you descend the column?

There is an increasing demand of support and to withstand more weight/pressure

The vertebral arch is comprised of the

Pedicle and lamina

The pedicle of the vertebral arch is

A cylindrical process that projects posterior from the body to meet with the laminae

The lamina of the vertebral arch is

A flat process that projects posteromedial to meet at the midline

The vertebral foramen is made up of

2 pedicles, 2 laminae, and the posterior surface of the vertebral body

The vertebral notches are

Indentations on the superior and inferior surfaces of each pedicle

The intervertebral foramen are formed from

The inferior notch of one vertebra, the superior notch of the vertebra beneath it, and the IV disc between the two vertebra

The superior and inferior articular processes of the vertebra project

Superiorly and inferiorly from the junction of the pedicle and lamina

The zygapophyseal joint is formed from the

Articular facet of the inferior articular process and the articular facet of the superior articular process of the vertebra beneath it

Due to the orientation of the zygapophyseal joints, the amount of each movement

Varies depending on each vertebra

The zygapophyseal joint is what type of joint?

Synovial; planar

The zygapophyseal joint is innervated by

PPRs of the corresponding segmental level

What are the motions of the zygapophyseal joint?

- Flexion/extension

- Lateral flexion

- Extension

Since each spinal division has different orientations of the facet joint, what is is possible

Different ranges of each movement

Cervical facet joints are at an angle of _ and allow for

45 degrees in the AP plane; all motions

Thoracic facet joints are _ and allow for

Vertical in the frontal plane; rotation and lateral flexion with some flexion and extension

What limits lateral flexion of the spine?

The ribs

The lumbar facet joints are _ and allow for

Vertical in the sagittal plane; flexion and extension with minimal rotation and lateral flexion

The 10th rib primarily articulates with the _ but does not always articulate with the _

10th vertebrae; 9th vertebrae

The anterior longitudinal ligament is fibrous band that extends from the _ to the _

Anterior tubercle of C1 to the sacrum; Anterior aspects of vertebral bodies and IV discs

The anterior longitudinal ligament limits

Spinal extension

The posterior longitudinal ligament is a fibrous band that extends from _ and attaches to _

The posterior aspect of C2 to the sacrum; The posterior aspects of the IV discs and loosely to posterior aspect of vertebral bodies

The posterior longitudinal ligament limits

Spinal flexion

Aside from being a spinal flexion limiter, what other purpose does the posterior longitudinal ligament serve

Prevention of posterior disc herniation

Ligamentum flavum connect

Adjacent lamina

What does the ligamentum flavum resist

Separation of the laminae during spinal flexion

The interspinous ligament connects

The bodies of adjacent SPs

The interspinous ligament limits _ and helps to maintain _

Spinal flexion; space between the SPs

The supraspinous ligament connects

The tips of SPs from C7 to the sacrum

At the cervical spine, the supraspinous ligament will become the

Nuchal ligament and attach to the occiput

The function of the supraspinous ligament is to

Limit spinal flexion and maintain space between SPs

The intertransverse ligament connects

Adjacent transverse processes

The function of the intertransverse ligament is to

Limit spinal lateral flexion and maintain space between the TPs

C7 (vertebra prominens) is at the level of which deep structures?

Apex of the lungs of thyroid isthmus