Posterior Triangle Flashcards
Floor of posterior triangle
prevertebral layer of deep cervical fascia splenius capitis m levator scapulae m. -posterior scalene m. -middle scalene m. -anterior scalene m. roots of brachial plexus
Splenious capitis m attachment
-from the ligament nuchae and the spinous process of C7-T3 to occipital bone and mastoid process
Levator scapulae m.
-Transverse process of C2-C4 to superior medical angle of scapula
Posterior scalene m.
-Transverse process of C4-C6 to 2nd rib
Middle scalene m.
-Transverse process of C4-C6 to 1st rib
Anterior scalene m.
-Transverse process of C4-C6 to 1st rib
Cercical Plexus
- Level of origin–Ventral rami of C2, C3, & C4 with contribuation from C1 and C5
- Sensory branches of plexus
- Cervical plexus block
- Motor branches of the plexus
Sensory branches of the plexus
-Lesser occiptal (C2) sometimes C3
-Great auricular (C2,C3)
-Transverse cervical (c2, C3)
Supraclavicular (C3, C4)
Deep cervical fascia
- 3 layers + carotid shealth
- —Investing layer, prevertebral layer, pretracheal layer
- functions—-supports organs, blood vessels…forms natural cleavage spaces, and allows movements of organs during swallowing and turning head
Investing layer
-surrounds the entire neck deep to the superficial fascia
-splits to go both sides of superficial muscles (trap, SCM, strap m.)
Anterior part of neck will split to surround the submandibular gland & form capsule of parotid gland
Prevertebral layer
- surrounds the vertebral column and muscles closely associated with it
- extends from hyoid to to thorax
- tubular sheath that surrounds deep back muscles
- base of skull to T3
- extends laterally as axiallary sheath
- forms floor of posterior triangle
- retropharyngeal space-potential space between the prevertrbarl fascia & teh fascia of pharynx
Pretracheal layer
- very thin layer in the anterior part of the anterior triangle
- surrounds the trachea, esophagus, & thyroid gland
- helps form the visceral compartment
- blends laterally with carotid sheath
Roof of the posterior triangle
- deep cervical fascia
- superficial cervical fascia containing superficical veins and nerves
- platysma m
- skin
Sensory branches of plexus (cervical plexus)
- exit from posterior part of SCM -nerve point
- joined by post ganglionic sympathetics
Lesser occipital
- C2–sometimes C3
- Supplies the skin of the neck and scalp posterosuperior to the auricle
Greater auricle
- C2, C3
- travels superomedically across the SCM with the external jugular vein..aka.. goes up the SCM in the middle with the external jugular
- Supplies the skin inferior to the auricle, over the parotid gland and posterior part of auricle
Transverse cervical
- C2, C3
- goes across the SCM-crossses it horizontally
- supplies the skin over the anterior triangle
Supraclavicular
- C3, C4
- Originates as a single trunk but divides into 3 branches
- –medial branch, intermediate branch, lateral branch
- supplies the skin over the clavicle & the superior wall of the chest and anterolateral part of the shoulder
Motor branches of cervical plexus
- Ansa cervicalis
- Phrenic nerve
Ansa cervicalis
- C1, C2, C3
- superior ramus—-C1, C2
- inferior ramus—-C2, C3
- branches of ansa cervicalis supply the strap muscles of neck (sterohyoid, sternohyoid, superior and inferior bellies of omohyoid)
- C1 fibers of plexus which contribure to the superior ramus of the ansa cervicalis supply the thyrohoid and geniohyoid muscles only
Phrenic nerve
- C3, C4, C5
- motor supply to the diagram–sole motor nerve to it
- also supplies the pericardium and part of the pleura
- damage to the nerve will cause paralysis to 1/2 of the diaphragm of affected side
- sensory to the central part of the diaphragm
C2 sensory nerves
-lesser occipital, great auricular, transverse cervical
C3
-great auricular, transverse cervical, supraclavicular—3 branches-lateral, intermediate, medial
C4
-supraclavicular
Spinal Accessory nerve
- cranial nerve XI
- motor supply to the trapezius and SCM
- courses obliquely across the posterior triangle dividing it into two equal halves
