Thoracic Osteology, Arthrology and Myology

Question 1

Contents/boundaries of superior thoracic aperture (thoracic inlet)

Answer 1

Trachea/esophagus
Nerves and vessels supplying neck and UE
Boundaries: T1 vertebrae, 1st ribs and superior manubrium

Question 2

Contents and boundaries of inferior thoracic aperture

Answer 2

Esophagus, inferior vena cava, aorta

Boundaries: T12, 11th/12th ribs, 7-10th costal cartilages and xiphisternal joint

Question 3

Divisions of thoracic cavity

Answer 3

Two pulmonary cavities laterally, which contain lungs and pleurae
Mediastinum, contains heart, thoracic great vessels, trachea, thoracic esophagus and thymus

Question 4

Manubrium costal notches articulate with

Answer 4

1st rib and half of the 2nd rib

Question 5

Costal notches of the sternal body articulate with

Answer 5

half of 2nd, 3rd-6th and half of 7th ribs

Question 6

Xiphoid process articulates with

Answer 6

Half of 7th rib

Question 7

Types of ribs

Answer 7

True ribs (vertebrocostal): 1-7th, attach directly from vertebral segments to sternum via their own costal cartilage
False ribs (vertebrochondral): 8-10th attach from vertebral segments to join the costal cartilage immediately superior to that segment
Floating (vertebral) ribs: 11-12th- do not attach to sternum at all

Question 8

Typical ribs

Answer 8

3-9th
Superior articular facet articulates with inferior costal demifacet on thoracic vertebral body one segment superiorly
Inferior articular facet articulates with superior costal demifacet on thoracic vertebral body of the same numeral segment
Tubercle- contains nonarticular part that is attachment point for lateral costotransverse ligament

Question 9

Atypical ribs

Answer 9

1, 2, 10-12th

Question 10

1st rib

Answer 10

Scalene tubercle- attachment for anterior scalene M.
Groove for subclavian artery
Groove for subclavian vein

Question 11

Second rib

Answer 11

Tuberosity of serratus anterior M.

Question 12

10-12th ribs

Answer 12

Nothing special, only have head, no tubercle or neck

Question 13

Most commonly fractured ribs

Answer 13

Middle ribs, at their weakest locus, just anterior to the costal angle
Can damage internal organs and produce severe pain

Question 14

Supernumerary ribs

Answer 14

Extra ribs either in the cervical region or lumbar region. Cervical ribs typically produce no symptoms, however, can produce neural and circulatory problems based on their proximity to the brachial plexus and subclavian A.
Lumbar ribs also often produce no symptoms, however, can result in confusion when reading radiographs and such

Question 15

Types of synovial joints

Answer 15

Planar- flat/gliding
Ginglymus- hinge
Trochoid- pivot
Condylar- concave
Sellar- saddle
Spheroidal- ball and socket
Compound synovial - combination of above

Question 16

Fibrous joints

Answer 16

Sutures
Schindylesis- tongue in groove
Gomphosis- peg in socket
Syndesmosis- bone-ligament-bone

Question 17

Cartilagenous joints

Answer 17

Synchondrosis- hyaline cartilage - temporary/growth plates

Symphysis- secondary cartilage joints- fibrocartilage

Question 18

Manubriosternal joint

Answer 18

Symphysis
Sternal angle of louis
2nd costal notch

Question 19

Xiphisternal joint

Answer 19

Synchondrosis
Inferior limit of the thorax
7th costal notch

Question 20

Sternocostal joints

Answer 20

Rib 1- synchondrosis

Ribs 2-7: synovial planar - anterior/posterior radiate sternocostal ligaments

Question 21

Costovertebral joints

Answer 21

Synovial planar
Radiate ligament- head of rib to vertebral body
Intraarticular ligament- head of rib to intervertebral disc
Articular capsule- strongest anteriorly as the radiate ligament

Question 22

Head of rib - vertebral articulations

Answer 22

Head of rib articulates with inferior costal facet of superior numeric thoracic vertebral segment and superior costal facet of the same numeric thoracic vertebral segment
The articulating facet of the costal tubercle articulates with the same numeric thoracic vertebral segment

Question 23

Costotransverse joint

Answer 23

Synovial planar
Lateral costotransverse ligament- tubercle of rib to transverse process
Superior costotransverse ligament- neck of rib to transverse process one vertebral segment superiorly

Question 24

Costovertebral joint movement

Answer 24

Two types of movement, both increase thoracic volume and decrease thoracic pressure during inspiration

• Bucket handle movement- elevation of the lateral most portion of the rib, increasing transverse diameter of thorax
• Pump handle movement: elevation of sternal end of rib, increasing anterior-posterior diameter of thorax

Question 25

Dislocation vs separation

Answer 25

Dislocation refers to dislocation at a sternocostal joint

Separation of ribs refers to a separation at the costochondral joint

Question 26

External intercostal muscle

Answer 26

11 pair; anteriorly, muscle fibers are replaced by the external intercostal membrane which overlies the internal intercostal muscles
Inferiorly, the external intercostal muscle is continuous with the external abdominal oblique muscle
Action- elevate the ribs
Innervation- intercostal nerve

Question 27

Internal intercostal muscles

Answer 27

11 pair; posteriorly, muscle fibers are replaced by the internal intercostal membrane
Inferiorly, the internal intercostal muscle is continuous with the internal abdominal oblique muscle
Action- depress ribs
Innervation- intercostal nerve

Question 28

Innermost intercostal muscle

Answer 28

11 pair; the deepest fibers of the internal intercostal muscle separated by the intercostal nerve and vessels
Action- undetermined, probably the same as internal int. muscle
Nerve- intercostal nerve

Question 29

Thoracentesis

Answer 29

Insertion of a hypodermic needle through the intercostal musculature b/w ribs to obtain a fluid sample or drain blood from pleural cavity.
Needle is inserted inferior to intercostal neurovascular bundle, but superior to the collateral branches

Question 30

Thoroscopy

Answer 30

Insertion of a thoroscope into the pleural cavity through small incisions for visualizing and biopsying the space inside the cavity

Question 31

Transverse thoracic muscle

Answer 31

O- posterior surface of lower part of sternal body
I- internal surface of 2-6th costal cartilages
A- depress ribs
N- intercostal n.

Question 32

Subcostal muscle

Answer 32

O- inferior border of rib
I- superior border of rib
A- similar to internal intercostal
N- intercostal n.