Deep Neck, Root of Neck, & Scalenes

Which are the deep lateral neck muscles?

• Rectus capitus lateralis

• Splenius capitis

• Levator scapulae

• Middle scalene

• Posterior scalene

Which are the deep anterior neck muscles?

• Rectus capitis anterior

• Anterior scalene

• Longus colli

• Longus capitis

Which structures are part of the root of the neck?

• Subclavian artery (3 parts)

• Nerves

• Veins

Which structures make up the pharynx?

• Nasopharynx → nose

• Oropharynx → mouth

• Laryngopharynx → larynx (voicebox)

Which muscles does the brachial plexus pass between?

Anterior & middle scalenes

Where is the phrenic nerve located?

• Forms at the superior part of lateral border of anterior scalene

• Descends obliquely with IJV across anterior scalene

Where is the IJV located?

• Passes anterior to scalene tubercle

• Joins with subclavian to form brachiocephalic vein

• Helps form the venous angle

What is the significance of the anterior scalene on the subclavian artery?

It divides it into 3 parts

What are the boundaries of the thoracic aperture?

• Lateral → 1st pair of ribs & costal cartilages

• Anterior → manubrium of sternum

• Posterior → body of T1 vertebra

What vessels provide blood to the right side of the upper body?

• Brachiocephalic trunk

  • Right common carotid artery

  • Right subclavian artery

What vessels provide blood to the left side of the upper body?

• Left common carotid artery

• Left subclavian artery

Where is the 1st part of the subclavian?

Medial to anterior scalene

Where is the 2nd part of the subclavian artery?

Posterior to anterior scalene

Where is the 3rd part of the subclavian artery?

Lateral to anterior scalene

What are the 3 branches coming off of the 1st part of the subclavian artery?

• Vertebral artery

• Internal thoracic artery

• Thyrocervical trunk

What are the branches coming off of the thyrocervical trunk from the 1st part of the subclavian artery?

• Transverse cervical artery

• Suprascapular artery

• Inferior thyroid artery

• Ascending cervical artery

What branch comes off of the 2nd part of the subclavian artery?

Costocervical trunk

What are the branches coming off of the costocervical trunk from the 2nd part of the subclavian artery?

• Superior intercostal artery

• Deep cervical artery

What branch comes off of the 3rd part of the subclavian artery?

Dorsal scapular artery

Where is the subclavian vein located?

• Begins at lateral border of 1st rib

• Direct continuation of axillary vein

• Passes over 1st rib

• Separated by anterior scalene from subclavian artery

• Joins IJV at venous angle to form brachiocephalic vein

What does the thoracic duct drain?

• Bilateral LE

• Left trunk

• Left UE

• L head

What does the right lymphatic trunk drain?

• Right trunk

• Right UE

• Right head/neck

What does the brachial plexus consist of?

• Spinal nerves C5 - T1

• Peripheral nerves that are formed from multiple spinal levels

What is significant about the location of the brachial plexus?

Vulnerable to compression as it passes b/w anterior and middle scalene

What are 3 causes of thoracic outlet syndrome?

• Anterior scalene syndrome

• Cervical rib syndrome

• Pec minor tightness

Describe anterior scalene syndrome

Compression of subclavian artery/brachial plexus between anteiror & middle scalene

Why is anterior scalene syndrome most common in COPD patients?

COPD includes forced inspiration which will hypertrophy the scalene muscles as they are accessory breathing muscles

What is cervical rib syndrome?

Compression of brachial plexus & subclavian artery by an extra cervical rib on superior surface of 1st rib

How does pec minor cause thoracic outlet syndrome?

• Tightness increases compression

• Lays like a tourniquet over brachial plexus & axillary artery

Which nerves are found in the root of the neck?

• Vagus (carotid sheath)

• Phrenic

What is the function of the internal pharyngeal muscles?

Elevate & shorten pharynx during swallowing

What is the function of the external pharyngeal muscles?

• Contract to ensure food is propelled correctly down the esophagus

• Most responsible for swallowing

What nerves provide sensory functions to the pharynx?

• Upper → Glossopharyngeal (CN IX)

• Lower → Vagus (CN X)

What nerves provide motor functions to the pharynx?

• Pharyngeal plexus → CN X

• Stylopharyngeus → CN IX