Anatomy Test 3

4th intercostal space; majority of lungs lie underneath this line

Left: anterior to T12-L3

Right: T11-L4

Mediastinum

diaphragm encloses the thoracic cavity inferiorly

vertebrocostal, 1-7
Attach directly to the sternum via costal cartilages

Vertebrochondral, 8–10
Attach to the costal margin

11 & 12
Do not attach to the sternum

1st rib is broadest, shortest, and most sharply curved of the 7 trues.
Has grooves for subclavian vessels;
Only one articular facet on its head

2nd rib has
2 articular facets
Tubercles for muscle attachment

Ribs 10-12 have, like 1st rib,
only 1 articular facet on their heads.


Ribs 11 & 12: short, floaters
No necks
No tubercles

Bilateral costal facets (demifacets) on the bodies for articulation w heads of ribs [or one whole facet in atypical vertebrae]

Costal facets on transverse processes for tubercles of ribs [except for bottom 2-3]

Long slanted spinous process

Symphysis; adjacent vert bodies bound by IV disc

*Ant and Post Longitudinal ligaments

Synovial Plane of joint; Head of each rib W/ superior demifacet of corresponding vertebral body and inferior demifacet of vertebral body superior to it.

*Radiate and intra-articular lig's of head of rib

**Heads# 1,11,12 articulate only w corresponding vertebral body

Synovial plane of joint; Tubercle of rib + Transverse Process of corresponding vertebra

*Lateral and superior costotransverse

*** Ribs 11 and 12 dont articulate w corresponding transverse processes

1st: cartilaginous
1st costal cartilages w Manubrium

2-7th: synovial plane
Costal cartilages w Sternum

*Ant and Post Radiate Sternocostal ligaments

Saddle; sternal end of clavicle W manubrium AND 1st costal cartilage

*Ant and Post sternoclavicular ligaments, Costoclavicular ligaments

Costochondral joint

Interchondral joint

*Interchondral ligaments

Symphysis; manubrium + sternum body

Sternoclavicular joint

Costal cartilages

Subcostal space/ subcostal nerve

Xiphisternal joint

Manubriosternal and Xiphisternal joints

T2 (sup), T7 (inf) spinous process

T2 spinous process

where the 2nd costal cartilages attach. It lies at the level of the IV disc between T4 & T5

From osteogenic layer of preserved periosteum

just anterior to its angle

multiple rib fractures --> big part of thoracic wall moves freely, moving in and out during breathing

obvi painful, affects breathing

Failure of 12th rib pair to form or growth of extra cervical or lumbar rib.

C7 rib- may compress C8 and T1 spinal nerves, inferior trunk of brachial plexus, or subclavian artery (leading to ischemic muscle pain in upper limb)

Lumbar ribs- may confuse identification of vert levels in diagnostics

often from sternal body bc of its breadth and subQ position. Needle pierces thin cortic bone and enters spongy bone. Common for transplant or CA detection purposes

Costoclavicular syndrome

(a type of thoracic outlet syndrome)

Rib displacement of costal cartilage from Sternum; produces lump at dislocation

Dislocation of costochondral junction btwn rib and costal cartilage. Rib moves superiorly over the above rib.

In 3rd-10th ribs, this would tear perichondrium and periosteum.

vertically over ribs 2-6
2/3 over pectoralis major
1/3 over serratus anterior

Retromammary space lies between pec fascia and breast, allows mvmt

Lat thoracic a (Lateral Mammary Branches)
Internal thoracic a (Medial Mammary Branches)
Posterior intercostal a's (2nd, 3rd, and 4th intercostal spaces)

Lateral mammary veins -> Axillary vein

Medial mammary veins -> internal thoracic veins

*Venous drainage can reach the azygous system via intercostal veins

anterior and lateral cutaneous branches of the 2nd to 6th intercostal nerves

The nipple is innervated by the 4th intercostal nerve

These nerves conduct sensory fibers to the skin over the breasts, and to the smooth muscle of vessels

from nipple, areola, and lobules to SUBAREOLAR lymphatic plexus

Most drains into axillary nodes. Eventually into right lymphatic or thoracic ducts

Most of medial quadrant drains into parasternal nodes and internal thoracic veins--> contralateral breast or drain to the lymphatic or thoracic duct.

lateral branches of posterior intercostal vessels--> azygous system and into the thoracic duct.

(some drainage to the subdiaphragmatic nodes & liver)

long thoracic nerve may be damaged because of its location on the lateral thoracic wall, resulting in winged scapula

The thoracodorsal nerve could also be damaged

External intercostals- Membranous anteriorly, Continuous with External Oblique

Internal intercostals- Membranous posteriorly, Continuous with Internal Oblique

Inner intercostals- Membranous anteriorly & posteriorly

Innervated by intercostal nerves

Intercostal muscles = main

Ohters: scalene muscles, Posterior serratus muscles, Deep back muscles, e.g. levator costorum, and transverse thoracic muscles

Subcostal Muscles

Axillary Tail

Simple- breast removed down to retromammary space
Radical- removal of breast, pectorals, fat, fascia, and as many lymph nodes in the axilla and pec region as possible

(difficulty breathing)
When asthma/heart failure pt's struggle to breathe, accessory respiratory muscles assist the expansion of the cavity. They lean, to fix the pectoral girdle, so muscles are able to act on their rib attachments and expand the thorax

1. Thoracic Aorta --> Posterior Intercostal Artery
(Upper two originate from the superior thoracic artery, a branch from the costocervical trunk)

2. Internal Thoracic a.(--> Anterior Intercostal Arteries) --> superior epigastric a. and musculophrenic a.

2 Routes:

Internal thoracic veins (Runs parallel to artery)-
Drain into brachiocephalic veins

The azygos system-
Drains into the superior vena cava

Intercostal Nerves (Anterior rami of T1-11)

All pass from posterior to anterior, between innermost and internal intercostal muscles

"VAN" from superior to inferior, with collateral branches running right above the ribs

The inferior vena cava & right phrenic nerve and pericardiacophrenic artery

The esophagus and vagus nerves

The thoracic aorta and thoracic duct pass

Largest: Abdominal Aorta

Others: Pericardiacophrenic, musculophrenic, branches from intercostals, and branches from thoracic aorta

Phrenic nerve (C3-C5).

These penetrate the diaphragm and supply it from underneath

During inspiration, diaphragm contracts.. the rib cage expands vertically, laterally, and in the anteroposterior dimension
"Bucket and Pump Handle".. :/

During expiration, the diaphragm relaxes and the rib cage contracts

Hilum; Root of the lung

Pulmonary Ligament

Endothoracic fascia

RECESSES; Visceral & parietal pleura are separated in regions that are not invaded by lungs during quiet respiration

Left Lung: 2 lobes (sup and inf) w Oblique Fissure btwn. Main bronchus is INFERIOR to the pulmonary artery

Right Lung: 3 lobes incl Middle Lobe and Horizontal Fissure. Main bronchus is POSTERIOR to pulmonary arteries

Costomediastinal Recess

Bronchopulmonary segment

Blood pumped by the Bronchial artery was returned to the Left atrium by pulmonary AND bronchial veins

Costodiaphragmatic recess

Vagus Nerve

Each dome has different innervation, so injury to Phrenic nerve (motor) can paralyze half the diaphragm.

Xray will show paradoxical mvmt; instead of normally descending on inspiration, the paralyzed dome is pushed up by the abdominal viscera being compressed by the other side.
Also, the positive pressure from expiration will make that half fall

Local anesthesia of intercostal space; injection around intercostal nerve and collateral branches.

Complete loss of sensation does not occur (since areas of skin usually innervated by 2 adjacent nerves) unless 2 or more intercostal nerves in adjacent spaces are anesthetized

Pneumothorax

Sympathetic Trunks

Hydrothorax

Pulmonary Embolism

****The clot may block blood flow in part or completely – when the embolus is large, patient suffers acute respiratory distress due to a major decrease in the oxygenation of blood & may expire in minutes

Hemothorax