Clavicle, Thoracic Wall, Lungs & Diaphragm

Vocabulary-style flashcards covering key terms from the lecture notes (Pages 1–9).

Clavicle

Collarbone; sole bony attachment of the upper limb to the trunk via the sternoclavicular joint.

Conoid Tubercle

A bump on the inferior surface of the clavicle's lateral third; attachment site for the conoid ligament.

Acromial End of Clavicle

Lateral end of the clavicle that articulates with the acromion to form the acromioclavicular (AC) joint.

Sternal End of Clavicle

Medial end of the clavicle that articulates with the sternum to form the sternoclavicular joint.

Clavicle Strut

Functions to maintain a set distance between the scapula/upper limb and the thorax, providing stability.

Clavicle S‑shape

Adds resiliency and strength and helps transmit forces from the upper limb to the axial skeleton.

Clavicle Force Transmission

handstand transmits force through clavicle to trunk

fall on outstretched hand causes force to travel up clavicle

Clavicle Weak Point

middle to lateral third junction

Clavicle Fracture

medial part elevates (pull of SCM)

lateral part drops (loss of bony connection for upper limb)

treat with sling to elevate/stabilize until healed

Epaxial Muscles

Dorsal trunk muscle group formed from somites

Hypaxial Muscles

Ventral/lateral trunk muscle group derived from somites; divided into six layers.

Hypaxial Layers (Superficial to Deep)

Supracostal

External Layer

Intermediate Layer

Internal Layer

Subvertebral Layer

Ventral Strap Muscles

Supracostal Layer

Above the ribs

Includes Serratus anterior and Pectoralis minor (plus rhomboids and levator scapulae)

External Layer

Outer layer between ribs, striations run lateral → medial

Intermediate Layer

Layer with Internal intercostals; fibers run perpendicular to external intercostals.

Internal Layer

Layer deep to external intercostals; assist with breathing and forced expiration

Innermost intercostals, subcostals, transversus thoracis

Subvertebral Layer

Hypaxial layer mostly absent in the thorax; longus colli extends into the upper thorax.

Ventral Strap Muscles

Deepest trunk; includes rare variants like the sternalis

Pectoralis Major

Large chest muscle; origin on the sternum, insertion on the humerus; anchors the upper limb to the axial skeleton; innervated by medial and lateral pectoral nerves

Intercostal Neurovasculature Bundle

Between internal and innermost intercostal layers; contains vein, artery, and nerve

Motor innervation to intercostal muscles

Cutaneous sensation to dermatomes

Intercostal Vein

superior position in the bundle

Intercostal Artery

middle position in the bundle

Intercostal Nerve

inferior position in the bundle

Thoracic Vertebrae

The twelve vertebrae T1–T12

True Ribs

Ribs 1–7 that attach directly to the sternum via their own costal cartilage.

False Ribs

Ribs 8–10 that attach indirectly to the sternum via cartilage

Floating Ribs

Ribs 11–12 with no anterior sternal attachment.

Sternum

the manubrium, the body, and the xiphoid process.

Sternal Angle

Angle between the manubrium and the body of the sternum; important clinical landmark.

Intercostal Spaces Naming

Space is named for the rib that sits above it

Right Lung

3 lobes: upper, middle, lower

2 fissures: horizontal, oblique

Left Lung

2 lobes: upper, lower

1 fissure: oblique fissure

contains lingula

Oblique Fissure

right lung: separates middle and lower lobes

left lung: separates upper and lower lobes

Horizontal Fissure

right lung: separates upper and middle lobes

Lingula

projection from left upper lobe; remnant of middle lobe lost during development

Trachea

Semiflexible airway with C-shaped cartilaginous rings; bifurcates at the carina into primary bronchi.

Carina

Bifurcation point of the trachea into the right and left primary bronchi.

Primary Bronchi

Enter lungs at the hilum

Right: is wider, shorter, more vertical

Left is narrower, longer, more horizontal.

Secondary Bronchi

Bronchi that supply each lung lobe; 3 for the right; 2 for the left

Tertiary Bronchi

Bronchi that supply bronchopulmonary segments; each segment has its own segmental bronchus.

Bronchopulmonary Segments

Discrete and surgically removable lung regions

Functionally independent lung units with their own bronchus, artery, and vein.

Sympathetic Airway Innervation

T1-T4; cause bronchodilation

Parasympathetic Airway Innervation

Medulla Craniosacral Region; cause bronchoconstriction

Bronchioles

smallest branches with cartilage and smooth muscle

Primary Breathing Muscles

main driver is diaphragm; intercostals elevate ribcage

Accessory Breathing Muscles

neck and abdominal muscles

Functional Residual Capacity

volume of air remaining in lungs after exhalation

Terminal Bronchioles

Smallest conducting airways before the respiratory zone; lead to alveolar ducts.

Alveolar Ducts

Airways leading to alveolar sacs; part of the gas exchange region.

Alveoli

Tiny air sacs where gas exchange occurs; large surface area with thin walls.

Primary Lobule

Functional unit of the lung: terminal bronchiole, respiratory bronchioles, alveolar ducts/sacs

Gas Exchange: Pulmonary Artery

Delivers deoxygenated blood to alveolar capillaries for oxygen uptake.

Gas Exchange: Oxygen

Travels from alveoli to the left atrium via pulmonary veins

Gas Exchange: Carbon Dioxide

Travels from blood to alveoli and bronchi, then exhaled

Conducting Zone

Air passages (nose to terminal bronchioles) that conduct air but do not gas-exchange.

Respiratory Zone

Gas-exchanging portion of the lungs (respiratory bronchioles, alveolar ducts, alveoli).

Upper Respiratory Tract

nose, pharynx, larynx

Lower Respiratory Tract

trachea, bronchi, bronchioles, alveolar ducts, alveoli.

Diaphragm

Primary muscle of respiration; dome-shaped muscle separating thorax and abdomen; central tendon anchors fibers.

Major Openings of Diaphragm

Aortic hiatus (T12), Esophageal hiatus (T10), Caval hiatus (T8)

Aortic Hiatus

Passage for aorta, azygos/hemiazygos veins, thoracic duct at T12.

Esophageal Hiatus

Passage for esophagus, vagus nerves, and esophageal arteries at T10.

Caval Hiatus

Passage for the inferior vena cava and branch of the right phrenic nerve at T8.

Diaphragm Arteries

left and right inferior phrenic

Diaphragm Veins

inferior phrenic

Phrenic Nerves

Nerves (C3–C5) that motor-innervate the diaphragm

Hiccups

Involuntary diaphragm spasms

Diaphragm in Respiration

inspiration: contracts to expand the thoracic cavity

Exhalation: relaxes to decrease the thoracic cavity