Gross Anatomy II Lab 4

External intercostal

Lateral, slants down toward pubis

Origin: Inferior border of ribs 1-11

Insertion: Superior border of ribs 2-12

Innervation: Corresponding intercostal nerves

Internal intercostal (11 pairs)

Medial, slants up toward manubrium

Origin: Superior border of ribs 2-12

Insertion: Inferior border of ribs 1-11

Innervation: Corresponding intercostal nerves

Innermost intercostal

Medial and deep, slants up toward manubrium

Origin: Superior border of ribs 2-12

Insertion: Inferior border of ribs 1-11

Innervation: Corresponding intercostal nerves

Transversus thoracis

Origin: Posterior surface of xiphoid process and body of sternum

Insertion: Inner surface of 2nd-6th costal cartilages

Innervation: Intercostal nerve

Subcostalis

At angle of the ribs only

Origin: Lower border of one rib

Insertion: After crossing a second rib, inserts in upper border of third rib

Innervation: Corresponding intercostal

Internal thoracic artery

Originates from subclavian artery

Branches: musculophrenic artery (lateral), superior epigastric artery (medial)

Internal thoracic vein

Drains to brachiocephalic vein, medial to internal thoracic artery

Intercostal vein, artery, nerve (VAN)

Found within intercostal space, superior to inferior

Linings of thoracic cavity

Visceral pleura

Parietal pleura, subdivides to:

1. Costal

2. Mediastinal

3. Diaphragmatic

4. Cervical

Costodiaphragmatic recess

Recess in thoracic cavity, lat. to diaphragm (V shape)

Features of superior mediastinum

Aortic arch (branches to brachiocephalic trunk, L common carotid and L subclavian a.)

Brachiocephalic trunk (branches to R common carotid artery, R subclavian artery)

Pulmonary trunk (branches to L and R pulmonary arteries)

Trachea (branches to L and R main bronchi) - between larynx and main bronchi

Esophagus - between pharynx and stomach

Branches of aortic arch

ABCS:

• Aortic arch

• Brachiocephalic trunk (R structure) → R subclavian, R common carotid a.

• L Common carotid a.

• L Subclavian a.

Features of middle mediastinum

Pericardium, pericardial cavity (between heart and pericardium), phrenic nerve, heart

Features of the pericardium

Fibrous pericardium, parietal and visceral layers of serous pericardium

Sinuses of pericardial cavity

Transverse pericardial sinus: behind aorta, in front of superior vena cava

Oblique pericardial sinus: behind apex of heart

Features of posterior mediastinum

Esophageal hiatus (in diaphragm), vagus nerves and branches (recurrent laryngeal nerves), thoracic aorta, superior vena cava and branches, thoracic duct, sympathetic trunk

Esophageal hiatus

Opening in diaphragm at T10

R and L recurrent laryngeal nerve

Branches of vagus nerve

R hooks under subclavian artery

L hooks under arch of aorta, posterior to ligamentum arteriosum

Esophageal plexus

Off the vagus nerve (superficial to esophagus)

Branches of superior vena cava

R and L brachiocephalic veins ← internal jugular vein, subclavian vein

Azygos vein ← hemiazygos vein, accessory hemiazygos vein, R superior intercostal vein

Thoracic duct

Between azygos vein and thoracic aorta - quack!

Features related to sympathetic trunk

Sympathetic chain ganglia, greater splanchnic nerve (sensory)

Features of sternum

Jugular notch, manubrium, body, xiphoid process, sternal angle

Features of typical rib (ribs 3-9)

Head, neck, tubercle, angle, costal groove, shaft