Large arteries of ( head , neck & U.L )

2026

📘 Large Arteries: Head, Neck, and Upper Limb – Exam-Focused Notes

🫀 Introduction: General Principles and Aortic Origin

Lecture Focus

• Exclusively covers arterial system.
• Specifically: arteries supplying Head, Neck, and Upper Limbs.

Blood Supply Source

• Heart's Aorta supplies blood to all body parts.
• Arch of Aorta gives rise to arteries supplying Head, Neck, and Upper Limbs.
• Rest of Aorta (Descending Aorta, Abdominal Aorta) supplies rest of body (trunk, lower limbs, etc.).

Major Branches

• Arch of Aorta gives three big branches.
• Four major arteries participate in supplying head, neck, and upper limb.

🔄 Differences: Right vs. Left Side Supply

Right Side Supply

• Single common artery: Brachiocephalic Artery (or Brachiocephalic Trunk).
• • Former name: Innominate Artery.
• Emerges first from arch.
• Divides into:
• • Right Subclavian Artery
  • Right Common Carotid Artery

Left Side Supply

• Two arteries arise separately (directly from Aortic Arch):
• • Left Common Carotid Artery
  • Left Subclavian Artery

Four Ultimate Arteries

• Two for head/neck: Common Carotid Arteries (Right and Left).
• Two for upper limbs: Subclavian Arteries (Right and Left).

Supply Overlap

• Overlap exists between supply regions.
• Example: Subclavian artery (primarily for upper limb) gives branches supplying head/neck structures.

📋 General Course Structure for Artery Discussion

For each major artery, three key items discussed:

1. Beginning (or Origin, if first arterial division).
2. Termination.
3. Big Branches.

🌳 Arteries Arising from Arch of Aorta

Three Arteries from Arch:

1. Left Subclavian Artery
2. Left Common Carotid Artery
3. Brachiocephalic Artery (Brachiocephalic Trunk)

Nomenclature Note

• Term "Innominate Artery" = very old, not preferred.
• "Brachiocephalic" used because gives two terminal branches:
• • Cephalic branch: For head
  • Brachial branch: For arm/upper limb

1️⃣ Brachiocephalic Artery (Brachiocephalic Trunk)

Origin (Exam Point)

• Arises from Arch of Aorta.

Specific Location

• Behind Manubrium Sterni (breastbone).

Course

• Runs towards right side and upward (laterally).
• Reaches root of neck at Right Sternoclavicular Joint.

Termination (Exam Point)

• Ends behind Right Sternoclavicular Joint.

Branches

Two terminal branches:

1. Right Subclavian Artery
2. Right Common Carotid Artery

2️⃣ Left Common Carotid Artery

Origin

• Arises directly from Arch of Aorta.
• Behind Manubrium Sterni (similar to Brachiocephalic Trunk).

Course

• Runs laterally towards left side.
• Travels upward towards neck.

Termination

• Reaches level of disc between C3 and C4 vertebrae.
• From front: corresponds to Cricoid Cartilage.

Entrance to Neck

• Enters neck behind Left Sternoclavicular Joint.

3️⃣ Left Subclavian Artery

Origin

• Arises directly from Arch of Aorta.
• Behind Manubrium Sterni.

Course

• Courses towards Left Sternoclavicular Joint.

Branches in Thorax

• Gives no branches inside thorax.

Continuation/Route

• Proceeds through root of neck.
• Passes under the clavicle and over First Rib.
• Naming reason: Sub = under, clavian = clavicle.

Landmark

• Visible clear groove on upper surface of First Rib.
• Formed by pressure of high-pressure artery.

Termination

• Ends at Outer Border of First Rib.

🔀 Subclavian Artery: Course and Branches in Neck

Transition to Axillary Artery

Transition Point

• Outer Border of First Rib marks transition into Cervicoaxillary Canal (apex of axilla).

Name Change

• Upon entering axilla, artery immediately becomes Axillary Artery.
• Same continuous vessel, name changes based on anatomical region.

Subclavian Artery Course Summary

• Runs from Arch of Aorta → through root of neck → beneath clavicle and over first rib → terminates at outer border of first rib.

📏 Divisions of Subclavian Artery (Exam Point)

Divided by Scalenus Anterior Muscle into three parts:

1. First Part:
2. • Medial to Scalenus Anterior muscle.
2. Second Part:
3. • Behind Scalenus Anterior muscle.
3. Third Part:
4. • Lateral to Scalenus Anterior muscle (up to outer border of First Rib).

🌿 Branches of Subclavian Artery (Exam Point)

Subclavian Artery (mainly for upper limb) gives critically important branches in root of neck supplying major structures.

First Part Branches (Three Big Branches) (Exam Point)

Three branches emerge perpendicularly: one up, one down, one forward.

1. Vertebral Artery (Ascending Branch):
2. • Rises superiorly.
2. Internal Thoracic Artery (Anterior Branch):
3. • Runs forward.
3. Thyrocervical Trunk (Descending/Trunk Branch):
4. • Runs downward.
   • Definition note: Short artery = Trunk.

🧠 Detailed Vertebral Artery Supply (Exam Point)

Importance

• Vital artery.
• Supplies:
• • Spinal Cord
  • Brainstem
  • Posterior part of Brain

Course Protection (Mechanism/Example)

• As soon as arises, enters protective bony canal.
• Formed by Foramina Transversaria (holes in Transverse Processes of Cervical Vertebrae).
• Entry starts typically at Sixth Cervical Vertebra (C6).
• Continues through: C5 → C4 → C3 → C2 → C1 (Atlas).

Entry to Skull

• Enters Cranial Cavity through Foramen Magnum.

Union

• Near base of Pons (part of Brainstem).
• Right and Left Vertebral Arteries join → form single artery = Basilar Artery.

Termination

• Basilar Artery runs in front of Pons.
• Terminates at beginning of Midbrain.
• Divides into two terminal branches: Posterior Cerebral Arteries.

Branch Distribution

• Supplies surrounding muscles.
• Gives branches that unite → form Anterior Spinal Artery (supplies spinal cord).
• Medullary branches: Supply Medulla Oblongata.
• Cerebellar Arteries: Supply Cerebellum.
• Posterior Spinal Arteries: Supply spinal cord.

🦴 Detailed Thyrocervical Trunk Supply (Exam Point)

Target

• Supplies neck and associated structures.

Division

Immediately divides into three branches:

1. Inferior Thyroid Artery:
2. • Supplies large part of Thyroid Gland.
2. Deep Cervical Artery:
3. • Supplies deeper structures of neck.
3. Transverse Cervical Artery:
4. • Supplies back and structures like Trapezius and Rhomboid muscles.

Exam Note: Lecturer holds students responsible only for three main First Part branches (Vertebral, Thyrocervical Trunk, Internal Thoracic) and their general fate, NOT sub-branches of Thyrocervical Trunk unless specified in textbooks.

Second Part Branch (One Branch)

1. Costocervical Trunk:
2. • Supplies costae (ribs) and neck.
   • Divides into two branches:
   • • Superior (First) Intercostal Artery: supplies first intercostal space.
     • Deep Cervical Artery: supplies deep neck structures.

Third Part Branch (Zero Branches)

• Third Part of Subclavian Artery gives no branches.

🩺 Common Carotid Arteries (Right and Left)

Beginning in Neck

• Both enter neck behind respective Sternoclavicular Joints.

Origin Difference (Exam Point)

• Left Common Carotid: Arises directly from Aortic Arch.
• Right Common Carotid: Arises from Brachiocephalic Artery.

Termination (Exam Point)

• Both sides identical in course and termination.
• Terminate at level of disc between C3 and C4.
• Divides into two terminal divisions:
• 1. Internal Carotid Artery
  2. External Carotid Artery

Common Carotid Branches

• Gives no branches before terminal division.

🛡️ Carotid Sheath (Protection Mechanism)

Structure

• Common Carotid Artery runs inside strong fibrous tube = Carotid Sheath.
• Derived from deep cervical fascia.

Contents (Exam Point)

Three vital structures:

1. Common Carotid Artery (later Internal Carotid Artery)
2. Internal Jugular Vein (drains brain and head)
3. Vagus Nerve (Cranial Nerve X) – most important clinical nerve

Protection Range

• Sheath protects artery all the way up to Base of Skull.

1️⃣ Internal Carotid Artery (ICA)

Course

• Continues course of Common Carotid Artery inside Carotid Sheath.
• Runs up to Base of Skull.

Entrance to Skull

• Enters skull through Carotid Canal (in Base of Skull).

Target (Exam Point)

• Primary purpose: supply Brain (structures inside Cranial Cavity).

Branches in Neck (Exam Point)

• Gives no branches in neck while running inside sheath.
• Focused on target.

Intracranial Branches

Once inside skull:

• Tympanic Branch: Supplies ear (while in canal).
• Ophthalmic Artery: Supplies eye (after exiting canal).
• Hypophyseal Glands Branches: Supply Pituitary Gland (Master Gland of endocrine system).

Terminal Divisions (Exam Point)

Divides into two terminal branches:

1. Anterior Cerebral Artery
2. Middle Cerebral Artery

2️⃣ External Carotid Artery (ECA)

Course

• Exits protected Carotid Sheath at C3/C4 disc level.

Target

• Supplies structures outside Cranial Cavity.
• Includes: muscles of face, structures in neck/face.

Branches (Six Branches + Two Terminal Divisions) (Exam Point)

Anterior Branches (Three, superior to inferior):

1. Superior Thyroid Artery
2. Facial Artery
3. Lingual Artery

Medial Branch (One):

1. Ascending Pharyngeal Artery (to pharynx)

Posterior Branches (Two):

1. Occipital Artery (to occiput)
2. Posterior Auricular Artery (behind ear)

Terminal Divisions (Two):

1. Maxillary Artery
2. Superficial Temporal Artery

Common Carotid Summary

• Two Common Carotid Arteries = anatomically identical.
• Only difference: Origin (Aortic Arch vs. Brachiocephalic Trunk).

💪 Arteries of Upper Limb: Axillary Artery

Origin (Exam Point)

• Continuation of Subclavian Artery.

Starting Point

• Begins at Outer Border of First Rib.

Termination (Exam Point)

• Ends at end of axilla.
• Specifically: Lower Border of Teres Major Muscle.
• (Teres Major = lowest boundary of posterior wall of axilla).

Continuation

• Continues into arm as Brachial Artery.

📏 Divisions of Axillary Artery (Exam Point)

Divided by Pectoralis Minor Muscle into three parts:

1. First Part:
2. • Proximal to (above) Pectoralis Minor muscle.
2. Second Part:
3. • Posterior to (behind) Pectoralis Minor muscle.
3. Third Part:
4. • Distal to (below) Pectoralis Minor muscle.

🌿 Branches of Axillary Artery (Exam Point)

Number of branches reversed compared to Subclavian Artery:

• First Part: Gives one branch.
• Second Part: Gives two branches.
• Third Part: Gives three branches.

First Part Branch (One):

1. Superior Thoracic Artery:
2. • Supplies upper part of chest (thorax) and associated muscles.

Second Part Branches (Two):

1. Thoracoacromial Artery (Acromiothoracic Artery):
2. • Strange artery.
   • Immediately divides into four perpendicular branches:
   • • Acromial branch
     • Clavicular branch
     • Deltoid branch
     • Pectoral branch
2. Lateral Thoracic Artery:
3. • Runs down.
   • Supplies Serratus Anterior muscle.

Third Part Branches (Three):

1. Subscapular Artery (Largest Branch):
2. • Supplies scapular region.
2. Anterior Humeral Circumflex Artery:
3. • Forms ring around surgical neck of Humerus.
3. Posterior Humeral Circumflex Artery:
4. • Forms ring around surgical neck of Humerus.
   • Passes behind bone.

💪 Arteries of Upper Limb: Brachial Artery

Origin (Exam Point)

• Starts at Lower Border of Teres Major Muscle.

Course

• Runs along Humerus bone.
• (Arm = "Brachium").

Termination (Exam Point)

• Terminates in Cubital Fossa (crook of elbow).
• Specifically at Neck of Radius.

Terminal Branches

Divides into two terminal branches:

1. Radial Artery (runs with Radius bone)
2. Ulnar Artery (runs with Ulna bone)

🌿 Branches of Brachial Artery

1. Profunda Brachii Artery (Deep Artery of Arm)

• Largest branch.
• Supplies back (posterior compartment) of arm.
• Homologous to: Profunda Femoris Artery in lower limb.

2. Nutrient Artery

• Specific artery supplying bone itself.

Mechanism/Example:

• Bone = living tissue → requires rich blood supply.
• Periosteum supplies cortex.
• Nutrient artery:
• • Enters canal inside bone (nutrient foramen).
  • Runs uninterrupted to marrow cavity.
  • Supplies marrow and internal bone structures.
• Every bone in body has nutrient artery.

3. Muscular Branches

• Supply muscles surrounding artery as it travels through arm.

4. Ulnar Collateral Arteries

• Two branches traveling towards elbow joint on medial (ulnar) side:
• 1. Superior Ulnar Collateral Artery
  2. Inferior Ulnar Collateral Artery

🔄 Function of Collateral Arteries (Mechanism/Example)

Purpose

• Small channels forming anastomoses (connections) around joint.
• Ensure continuous blood flow to limb.
• Act as alternative pathway (collateral bypass).

Clinical Significance

• Maintain flow if main Brachial Artery becomes occluded.
• Causes of occlusion: injury, medical accident.

Terminal Branches Summary

1. Radial Artery
2. Ulnar Artery