Posterior Triangle of the Neck Flashcards
What is the origin of the Sternocleidomastoid muscle?
Sternum and clavicle (one head from each)
What is the insertion of the Sternocleidomastoid muscle?
mastoid process
What nerve supplies the Sternocleidomastoid muscle?
CN XI
What artery supplies the Sternocleidomastoid muscle?
sternocleidomastoid branch of the occipital artery
What is the action of the Sternocleidomastoid muscle?
unilaterally contracts head to the same said, bilaterally extends neck at atlanto-occipital joint, flexes cervical vertebrae, or thrusts chin forward while head is kept level
What noteworthy structure lies deep to the Sternocleidomastoid muscle?
The carotid sheath
What is the origin of the Platysma muscle?
subcutaneous fascia over pectoral region of chest wall (pec major and deltoid)
What is the insertion of the Platysma muscle?
inferior border of the mandible and skin of lower face
What nerve supplies the Platysma muscle?
cervical branch of CN VII
What artery supplies the Platysma muscle?
facial artery
What is the action of the Platysma muscle?
muscle of facial expression, draws corners of mouth down and aids in depression of mandible
What is noteworthy about the Platysma muscle?
derived from mesenchyme of second pharyngeal arch
What is the origin of the Posterior Scalene muscle?
TP (transverse process) C4-C6
What is the insertion of the Posterior Scalene muscle?
2nd rib
What is the nerve supply of the Posterior Scalene muscle?
anterior rami of C7-C8
What artery supplies the Posterior Scalene muscle?
ascending cervical artery
What is the action of the Posterior Scalene muscle?
elevates second rib, flexes and laterally bends the neck
what is noteworthy about the Posterior Scalene muscle?
muscle of respiration; longest of scalene muscles
What is the origin of the Middle Scalene muscle?
TP C4-C6
What is the insertion of the Middle Scalene muscle?
1st rib
What is the nerve supply of the Middle Scalene muscle?
ventral rami of C3-C8
What is the blood supply of the Middle Scalene muscle?
ascending cervical artery
What is the action of the Middle Scalene muscle?
elevates first rib, flexes and laterally bends neck
What is noteworthy about the Middle Scalene muscle?
muscle of respiration, penetrated by the dorsal scapular nerve and long thoracic nerve
What is the origin of the Anterior Scalene muscle?
TP C4-C6
What is the insertion of the Anterior Scalene muscle?
1st rib
What is the nerve supply of the Anterior Scalene muscle?
ventral rami C4-C6
What is the blood supply of the Anterior Scalene muscle?
ascending cervical artery
What is the action of the Anterior Scalene muscle?
elevates first rib, flexes and laterally bends the neck
What is noteworthy about the Anterior Scalene muscle?
muscle of respiration, located between subclavian vein and subclavian artery. Root of brachial plexus pass posterior to it. Phrenic nerve crosses anterior surface.
What is the origin of the Splenius Capitus muscle?
ligamenum nichae and SP C7-T3
What is the insertion of the Splenius Capitus muscle?
occipital bone and mastoid process
What is the nerve supply of the Splenius Capitus muscle?
Dorsal primary rami of C2-C6
What is the blood supply of the Splenius Capitus muscle?
deep cervical artery
What is the action of the Splenius Capitus muscle?
extends and laterally bends the neck and head, rotates head to same side
What is the origin of the Levator Scapulae muscle?
TP C2-C4
What is the insertion of the Levator Scapulae muscle?
superior angle of scapula
What is the nerve supply of the Levator Scapulae?
dorsal scapular nerve
What is the blood supply of the Levator Scapulae?
dorsal scapular artery
What is the action of the Levator Scapulae?
elevates the scapula
What are the boundaries of the Posterior Cervical Triangle?
Posterior border of SCM, anterior border of trapezius, middle third of clavicle. (It is further divided into the subclavian triangle and the occipital triangle)
What are the boundaries of the Subclavian Triangle?
inferior belly of omohyoid, SCM and middle third of clavicle. (Contains parts of external jugular vein and the subclavian artery)
What cranial nerve crosses the Occipital Triangle?
CN XI
What are the muscles of the Posterior Triangle of the Neck?
Sternocleidomastoid, Platysma, Posterior Scalene, Middle Scalene, Anterior Scalene, Splenius Capitus, and Levator Scapulae