9: Posterior Neck Flashcards
platysma m.
- very superficial facial muscle - for frowning
- Platysma means plate-like or flat
- First muscle of facial expression that we’ve learned. Innervated by facial nerve VII.
- Originates in subcutaneous tissue - Covers over pec major
- Inserts into mandible and fascia of the cheek – tenses the fascia
plastysma innervated by
CN VII - facial
platysma origin
Origin - subcutaneous tissue over pectoralis major and deltoids
platysma insertion
Insertion - mandible and fascia of cheek
platysma action
Main action: draws corners of mouth inferiorly and widens it as in expressions of sadness and fright
platysma plays only a minor role in depressing the lip which is primarily performed by the depressor anguli oris and the depressor labii inferioris
posterior cervical triangle boundaries
posteriorally = trapezius m. anteriorally = SCM m. inferiorally = clavicle
what separates the posterior cervical triangle from the anterior cervical triangle?
sternocleidomastoid m.
what is visible in the posterior cervical triangle from the skin? (superficial anatomy)
trapezius
external jugular vein
clavicular and sternal heads of SCM
superficial veins of the posterior cervical triangle
posterior auricular drains into external jugular vein
retromandibular posterior division drains into external jugular vein
anterior division goes to the facial vein
external jugular drains to subclavian vein which drains to the SVC
SCM actions
side flexion of the head to the same side
rotating the head to the opposite side
posterior auricular v. drains into the
external jugular v.
retromandibular posterior v. drains into the
external jugular v.
retromandibular anterior v. drains into the
facial v.
external jugular v. drains into the
subclavian v. which drains into the superior vena cava
posterior triangle borders
Anterior - Sternocleidomastoid m.
Posterior - Trapezius m.
Inferior - Clavicle
posterior cervical triangle subdivided into two triangles
Occipital - above the omohyoid
Supraclavicular - below the omohyoid
muscle that bisects the posterior cervical triangle
inferior belly of omohyoid m.
occipital triangle borders
Anterior: Sternocleidomastoid
Inferior: Inferior belly of the omohyoid
Posterior: Trapezius
contents of occipital triangle
Cutaneous nerves of cervical plexus:
Lesser occipital nerve, from C2-C3
Great Auricular nerve, from C2-3
Transverse cervical nerve, from C2-3
Lateral, intermediate and medial supraclavicular nerves, from C3-4
Spinal accessory (CN XI) nerve to sternocleidomastoid and trapezius muscles
Floor:
Splenius capitis, levator scapulae muscles
“Scalene muscles” (middle/posterior) when trapezius and SCM are removed
Cutaneous nerves of cervical plexus:
Lesser occipital nerve, from C2-C3
Great Auricular nerve, from C2-3
Transverse cervical nerve, from C2-3
Lateral, intermediate and medial supraclavicular nerves, from C3-4
nerves from C2-C3
lesser occipital
greater auricular
transverse cervical
nerves from C3-C4
lateral, intermediate, and medial supraclavicular nerves
Spinal accessory (CN XI) nerve innervates
sternocleidomastoid and trapezius muscles (motor only)
floor of occipital triangle
Splenius capitis, levator scapulae muscles
“Scalene muscles”
cervical plexus formed by
union of adjacent ventral rami of the first 4 cervical nerves
cutaneous branches of the cervical plexus
Cutaneous (sensory) branches arise around the middle of the posterior border of SCM
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular nn.
(Lat, Med, Int.)
most posterior cutaneous branch of cervical plexus
Lesser Occipital
cutaneous n. anterior to the lesser occipital n.
great auricular n.
wraps around anterior border of SCM
transverse cervical n.
Great auricular nerve (GA) innervates
ascends vertically over the parotid gland where it divides and supplies the skin over the gland, the posterior aspect of the auricle
Lesser Occipital nerve (LO): path and innervates
supplying the skin of the neck and scalp posterosuperior to the auricle (scalp above the ear)
Transverse cervical nerve (TC): path and innervates
supplying the skin covering the anterior cervical region; passes from the posterior border of SCM; supplies sensory innervation to the skin in that area
Supraclavicular nerves (SC): path and innervates
Emerge as a common trunk under the SCM and send small branches (Lateral LSC, Medial MSC, Intermediate ISC) to the skin of the neck and cross the clavicle to supply the skin over the shoulder
cervical plexus nerve block
For surgical procedures in the neck region or upper limb, anesthetic is injected at several points along the posterior border of SCM, mainly at the Nerve point of the neck.
spinal accessory path
Emerges from middle of posterior border of SCM, crosses occipital triangle and passes deep to the superior border of the trapezius to innervate it.
occipital triangle muscles include
(in order from posterior to anterior) splenius capitus levator scapulae posterior scalene (2nd rib) middle scalene (1st rib) anterior scalene (1st rib)
borders: trapezius, SCM, omohyoid inferior belly
which nerve courses over the anterior scalene m.?
phrenic n.
location of the cervical plexus
deep to the SCM, except for the transverse cervical n. which travels on its surface
cervical plexus formed by
union of adjacent ventral rami of the first 4 cervical nerves
supraclavicular triangle borders
(the little triangle of the posterior triangle)
Anterior: Sternocleidomastoid
Superior: Inferior belly of the omohyoid
Inferior: Clavicle
contents of supraclavicular triangle
(the little triangle on the posterior neck)
Phrenic nerve :C3,4,5
Brachial plexus (roots, trunks, and some branches)
Subclavian artery
Transverse cervical artery
Dorsal scapular artery
Suprascapular artery
Subclavian vein
course behind (posterior to) the anterior scalene m.
Subclavian artery + brachial plexus
courses over (anterior to) the anterior scalene m.
Subclavian vein
roots of brachial plexus
Ventral rami of spinal n. C5-T1
trunks of brachial plexus
Ventral rami C5&C6=upper trunk
Ventral rami C7=middle trunk
Ventral rami C8&T1=lower trunk
to stop upper limb bleeding
press subclavian a. against the ribs
anterior surface of scalene muscle
Phrenic Transverse cervical Suprascapular a Subclavian v \+ more, will see later (vagus)
dorsal scapular a. a continuation of
the transverse cervical a.
branches of subclavian artery
Vertebral artery Thyrocervical trunk: Transverse cervical artery Suprascapular artery Ascending cervical artery Inferior thyroid artery
Costocervical trunk:
- Deep cervical artery
- Supreme intercostal artery
floor of supraclavicular triangle
middle and posterior scalene muscles
dorsal scapular n. branches from
ramus of C5
suprascapular n. branches from
upper trunk
long thoracic comes from
rami of C5-C7
boundaries of the anterior part of the neck
Superior: Body of mandible, mastoid process of temporal bone
Anterior: midline
Inferior: Clavicle, manubrium of sternum
Posterior: Trapezius m., anterior border
