Posterior Triangle Flashcards
SCM
Originates from the Sternum
Inserts onto mastoid process
External Jugular Vein
Prominent when straining
Used to monitor blood pressure
Boundaries of Posterior Triangle
SCM divides neck into two cervical triangles=anterior and posterior
Anteriorly: posterior border of SCM
Posteriorly: anterior border of trapezius
Inferiorly: middle third of clavicle
Apex: SCM meets trapezius near occipital bone
Subclavian Triangle
Bounded by
Inferior belly of omohyoid, SCM and trapezius
Apex: occipital bone
CN XI (spinal accessory nerve) crosses triangle
Superficial cervical fascia
Fatty sub cutaneous tissue-between skin and deep fascia
Contains: cutaneous nerves, blood vessels and lymphatic vessels, superficial lymph nodes and platysma muscle
Deep Cervical fascia
Forms organs and blood vessels
- allows movement during swallowing and turning head
1) Investing layer
2) Prevertebral layer=surrounds vertebral column and muscles associated
3) pretracheal layer
4) Carotid Sheath=fascia around great vessels to form neurovascular compartment of neck
Investing Layer
surrounds entire neck
- splits to go around superficial muscles SCM, strap muscles, and trapezius
- anterior part goes around submandibular and makes parotid capsule
Prevertebral Layer
From Hyoid bone to Thorax where it blends with pericardium
- Base of skull –> T3
- sheath around deep back muscles
- axillary sheath
- floor of posterior triangle
- Retropharyngeal space-prevertebral fascia and fascia of pharynx
Pretracheal Layer
Very thin anterior part of anterior triangle
- surrounds trachea, esophagus and thyroid gland
- blends laterally with carotid sheath
- helps form visceral compartment
Roof of Posterior Triangle
Deep Cervicle fascia (investing layer)
Superficial cervicle fascia
platysma muscle
skin
Floor Of Posterior Triangle
- Prevertebral layer of deep cerviicle fascia
- Splenius capitas m (from the ligament nuchae and the spinous process of C7-T3 to occipital bone and mastoid process) lies below fascial carpet
- Levator scapulae m (T process of C2-C4 to superior medial angle of scapula)
- Posterior scalene m
- middle scalene m
- Anterior scalene muscle
- Roots of Brachial plexus
Cervicle Plexus
Level of Origin
-Ventral Rami of C2 C3 C4 with contribution from C1 and C5
Sensory Branches of Cervicle Plexus
Exits from posterior part of SCM…joined by post ganglionic fibers
A. Lesser Occipital (C2,C3)=skin of neck and scalp, posterior to ear
B. Greater Auricular (C2,C3)=travels superomedially across SCM with external jug…skin inferior to to ear, over parotid and posterior part of ear
C. Transverse Cervicle (C2,C3)=goes across SCM…skin over anterior triangle
D. Supraclavicular (C3,C4)= medial, intermediate and lateral branches…skin over clavicle and superior wall of chest and anterolateral part of shoulder
Cervicle Plexus Block
Anesthesia Procedure to block C2-C4
Ansa Cervicalis
C1 C2 C3
Superior Ramus=C1,C2
Inferior Ramus=C2, C3
-Branches of the plexus supply the strap muscles of the neck (sternohyoid, sternothyroid, superior and inferior bellies of omohyoid)
-C1 fibers of plexus (contribute to the superior ramus) supply the thyrohyoid and geniohyoid muscles
