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1
N 15A
MA 584C
NECK- I
Lateral (Posterior) ! and Suboccipital !
Reading: Moore and Agur 583-596
M.Pizzimenti, Ph.D. OBJECTIVES:
• Identify the special characteristics of cervical vertebrae and describe the function of the
hyoid bone.
• Outline the borders and components of the triangles of the neck.
• Name and describe the muscles found in the posterior and anterior (sub) triangles of the
neck.
• Describe the principal sensory cutaneous nerves of the neck; describe area of cutaneous
innervation by these nerves; identify on a diagram the site of local anesthetic injection
that will produce the best results.
• Outline the layers of fascia of the neck, describe their location, function and contents.
• Describe the suboccipital triangle: List its borders and trace the course of the vertebral
a.,v.
• Describe and outline the clinical presentations of: torticollis, CN XI lesion, phrenic nerve
block, carotid endarterectomy, IJV jugular pulse, IJV puncture
Superficial Fascia
Deep to the skin and contains variable amount of fat, lymph vessels and nodes, nn., and platysma
m.
The Bony Skeleton of
the Neck
Cervical vertebrae:
• Seven in number
Typical features:
lamina, pedicle,
transverse process,
bifid spinous process
(C3-C6), foramina
transversarium
Atypical features:
Atlas (C1): anterior and posterior tubercles, no spinous process
Axis (C2): odontoid (dens) process
The hyoid bone:
U-shaped bone at C3 vertebral level
Body, and horns serve as the base for tongue and larynx.
Infrahyoid mm. attach here
Clavicle
See notes on upper extremity
2
MA 587B
MA 584
Cranium
• Mastoid process of temporal bone
• Nuchal lines
• External occipital protuberance
Muscular Triangles (Regions) of the Neck
Sternocleidomastoid • Attaches from the mastoid process to clavicle and sternum
• Ipsilateral action:
• Bilateral action:
• Supplied by CN XI and transverse cervical a.
Lateral region (Posterior !)
• Posterior !
- Borders: posterior
sternocleidomastoid (SCM), ant.
border of trapezius, and clavicle.
- Investing fascia contributes to roof
- Deep cervical mm. contribute to floor
• Occipital & Omoclavicular (subclavian) !
- Constituents of posterior !
- Defined by the omohyoid m.
- Borders
! Occipital !
! Omoclavicular !
Anterior region (Anterior !)
• Borders: Anterior SCM, inf. Mandible, median line of neck
• Superficial fascia and platysma contribute to roof
• Pharynx, larynx, and thyroid gland contribute to floor
• Contains smaller constituent triangles (e.g.,
carotid, submental, submandibular, and muscular)
Superficial Structures within the Posterior !
Vasculature
• External Jugular v. (EJV)
- Travels vertically along SCM to drain into
the internal jugular v. (IJV) deep to SCM:
drains eventually into subclavian v.
- Formed by the joining of the retromandibular
and post. auricular v.
3
MA 591A
MA 588
MA 584
Nerves
• Spinal accessory (CN XI)
- Motor supply to trapezius and
SCM
- Crosses ! approximately 1/3
of length of SCM from
mastoid process, runs along
levator scapulae
• Cutaneous branches of cervical
plexus
! Transverse cervical n. (C2 &
3): passes anterior to SCM,
deep to platysma and EJV;
sensory from anterior neck
! Great auricular n. (C2 &C3): ascends vertically, with the EJV, on SCM up to parotid
gland; sensory from post. auricle, skin over angle of mandible to mastoid process
! Lesser occipital n. (C2); travels along post. border of SCM; sensory from
posterior neck and scalp
! Supraclavicular nn. (C3 & C4); travels as a trunk deep to SCM and emerges
to send branches to shoulder and clavicle; sensory from this area.
! What would be the result of injecting an anesthetic agent at the point
where these nn. emerge? What would be lost?
! What would be the result of a lesion to the right CN XI?
! Describe torticollis
Deep Structures within the Posterior !
Muscles
• Splenius capitus m.
• Levator scapulae m.
• Anterior and Middle scalene mm.
- form interscalene triangle
- attach on transverse processes of C4-6 and on 1st rib
• Posterior scalene mm
- attach on transverse processes of C4-6 and on 2nd rib
! How might scalene mm. contribute to
respiration?
4
MA 584
MA 598C
MA 584
Vasculature
Arteries: transverse cervical, suprascapular,
subclavian (3rd part), occipital a.
• Subclavian a.
• Thyrocervical trunk: branch of subclavian a.
- Transverse cervical a.
- Suprascapular a.
- Inferior thyroid a. (later)
• Occipital a.
- Recall posterior neck dissection
Veins
• External Jugular v.
! Recall course
! Can serve as an internal barometer to
detect increased venous pressure:
becomes distended along its course
• Internal Jugular v.
- Inferior portion just deep to SCM at junction of sternal and clavicular heads
- Drains into subclavian v.
- Access point
• Subclavian v.
- Travels ant. to ant. scalene m.
- Access point
Nerves
• Spinal accessory (CN XI)
- Motor supply to
• Ventral Rami of brachial plexus
- Contribution from spinal nn.
?
- Passes through interscalene !
with subclavian a.
• Suprascapular n.
• Long Thoracic n.
• Dorsal scapular n.
- Usually pierces middle scalene m.
• Phrenic n.
- Runs vertically and anterior to ant. scalene m.
- C3-C5 supplies _____________
• Sensory nn. from cervical plexus already studied
5
MA 585
MA 584
Deep Cervical Fascia of the Neck:
Overview
• Acts as a barrier to prevent spread of
infection; lies deep to superficial
fascia and divides into layers to
enclose specific components of the
neck.
• Support viscera
• Provides cleavage planes through
which tissues may be separated during
surgery
• Limits spread of infection
• Facilitates movement of structures of neck.
Layers of the Deep Fascia
• Investing Layer:
! Surrounds the cervical
vertebrae and all the viscera
and muscles of the neck.
! Restricts abscesses
immediately deep to it from
spreading to the surface.
! Superiorly attached to
zygomatic arch and inferiorly
to the clavicle. Posteriorly
continuous with ligamentum
nuchae.
• Prevertebral Layer:
- Extends from the base of the
skull down to the level of 3rd
thoracic vertebra.
- It envelops the cervical
vertebrae, the scalene
muscles, and the prevertebral and postvertebral muscles of the
neck.
- It forms floor of the post triangle.
• Pretracheal Layer:
- envelops the thyroid gland and covers larynx, trachea and part
of esophagus
- extends from the hyoid bone to the fibrous pericardium.
6
• Retropharyngeal Space
! Lies between ___________ and ____________ layers
! permits movement of the pharynx, esophagus, larynx and trachea during swallowing.
• Carotid Sheath:
- sheath of deep cervical fascia that envelops the common and internal carotid arteries, the
internal jugular vein, the vagus nerve
- Cervical part of the sympathetic trunks lie embedded in loose connective tissue directly
posterior to the carotid sheath
Suboccipital Triangle
Deep to splenius and semispinalis capitus mm.
Muscles that comprise borders
Rectus capitus posterior major
Inferior oblique (capitus)
Superior Oblique (capitus)
Actions
Innervation
Other structures related to the area:
Greater occipital n (C2)
Vertebral a.
Rectus capitus posterior minor m.
MA = Moore, KL and Agur, AMR. 2007. Essential Clinical
Anatomy (3rd Ed), Lippincott Williams & Wilkins
MD = Moore, KL and Dalley, A. 1999. Clinically Oriented Anatomy (4th Ed), Lippincott Williams & Wilkins
GD = Tank, PW. 2005. Grant’s Dissector (13th Ed), Lippincott Williams & Wilkins
GA = Agur AMR and Dalley, A 2005. Grant’s Atlas of Anatomy (11th Ed), Lippincott Williams & Wilkins
N = Netter, FH. 2003, Atlas of Human Anatomy (3rd
Ed), Icon Learning Systems
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