Thoracic Wall

Question 1

Describe the branching of intercostal nerves:

Answer 1

Intercostal nerves are anterior rami of spinal nerves T1-T11

Lateral cutaneous branch (largest)

• Splits into anterior and posterior branches
• Ends as anterior cutaneous branch
• Lateral cutaneous branch pierces thoracic wall –> anterior and posterior branches innervate skin
• Collateral branches run along superior border of lower rib and supply: motor innervation to muscles of thoracic wall, somatic sensory innervation from skin and parietal pleura, postganglionic sympathetic fibres to periphery

Question 2

What are the parts of the axial skeleton?

Answer 2

skull, vertebrae, sacrum, hyoid bone, ribs and sternum

Question 3

What are the parts of the upper limb girdle

Answer 3

clavicles and scapulae (attach upper limbs to axial skeleton)

Question 4

What are the parts of the vertebral column, where do its nerves emerge and what is its direction of curvature

Answer 4

see notes

Question 5

What surface markings does the scapula provide

Answer 5

• Superior angle: T2 spine
• Spine: T3 spine
• Medial border: palpable
• Inferior angle: T7 spine

Question 6

How do thoracic vertebrae articulate with ribs?

Answer 6

transverse processes, which have facets for articulation with the tubercle of the associated ribs

• TI: complete costal factors allows TI to only articular with its own rib
• TII-TIX: have inferior and superior demifacets, with the superior demifacet articulating with the head of its own rib, and the inferior with that of the vertebrate below’s; transverse costal facets on transverse processes articulate with own rib
• TX: articulates only with own rib using both costal facets on the transverse process and pedicle
• TXI-TXII: articulate to own ribs only with costal facets on the pedicles

Question 7

What are the parts of vertebrae?

Answer 7

1. Vertebral Body: weight-bearing and linked to superior/inferior vertebra by inter-vertebral discs and ligaments - size increases inferiorly as must bear more weight
2. Vertebral Arch: forms the lateral and posterior region, with the vertebral foramen in the centre
3. Vertebral Foramen: all the foramina combined form the vertebral canal to contain and protect the cord
4. Pedicles: attach vertebral arch to body
5. Laminae: flat sheets extending medially from the pedicles to meet in the midline to enclose the vertebral arch
6. Spinous process: projects posteriorly and inferiorly from the junction of the laminae to allow for the attachment of muscles and ligaments (palpable CVII-TIV)
7. Transverse processes: extend posterolaterally from the pedicle-lamina junctions on each side to allow articulation (joining) with the ribs in the thoracic region
8. Superior/inferior processes: extend superiorly/inferiorly to interact with the inferior/superior processes of the adjacent vertebra respectively
9. Superior/inferior vertebral notches: superior/inferior aspects of the pedicles, forming the intervertebral foramina where the mixed spinal nerves may emerge

Question 8

What is the structure of the rib?

Answer 8

• Head: attaches to transverse processes of the thoracic vertebrae via articular facets
• Costal Cartilage: joins to the sternal articular facets
• Neck: posterior region of the rib

Question 9

Describe the bucket handle movement

Answer 9

when breathing in, ribs move superiorly and anteriorly in a handle-like movement, moving in the opposite direction during expiration

Diaphragm: flattens to increase lung volume on breathing in

Question 10

What does the internal thoracic artery bifurcate into?

Answer 10

form the musculophrenic and superior epigastric arteries just superior to the diaphragm

Question 11

What are the contents of the thoracic inlet?

Answer 11

○ great vessels heading for neck and upper limb (internal jugular vein, common carotid, subclavian artery, subclavian vein 
○ Oesophagus
○ Trachea
○ nerves 
○ lymphatics

Question 12

What type of joint do ribs form with vertebrae and costal cartilage

Answer 12

all synovial except R1 with manubrium is cartilagenous

Question 13

How do 2 vertebral bodies connect?

Answer 13

Connect via Inferior Articular Process + Superior articular process

Hyaline cartilage + Intervertebral disc in between

Joints between vertebral arches are zygapophysial joints

Question 14

What are intervertebral discs made of?

Answer 14

Anulus fibrosus (collagen – limits rotation)
Nucleus pulposus (gelatinous – absorbs compression forces)