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The side of the neck lies between the midline anteriorly and the anterior border of trapezius posteriorly.
It contains important neurovascular structures, lymph nodes, and muscles.
Functionally, it acts as a connecting region between the head, thorax, and upper limb.
Anterior boundary: Midline of the neck.
Posterior boundary: Anterior border of the trapezius.
Superior boundary: Inferior border of mandible and line from its angle to mastoid process.
Inferior boundary: Upper border of clavicle.
The side of neck is divided by sternocleidomastoid (SCM) into:
Anterior triangle
Posterior triangle
Anterior: Anterior border of sternocleidomastoid (SCM).
Posterior: Anterior border of trapezius.
Superior: Base of mandible and mastoid process.
Inferior: Clavicle.
Thin and loosely attached over the neck, except along the lower part where it is firm.
Supplied by:
Lesser occipital nerve (C2)
Great auricular nerve (C2, C3)
Transverse cervical nerve (C2, C3)
Supraclavicular nerves (C3, C4)
Lies deep to the skin and contains:
Platysma muscle – a thin subcutaneous sheet of muscle extending from thorax to mandible.
Cutaneous nerves (as above).
External and anterior jugular veins.
Superficial lymph nodes (like external jugular and anterior cervical).
Clinical relevance: Injury to platysma → skin scar adhesion if not sutured separately.
Incision along upper border of clavicle, reflect skin upwards to anterior border of trapezius.
Identify platysma, anterior cutaneous nerve, and anterior jugular vein.
Remove superficial fascia to expose deep cervical fascia.
External jugular vein appears above clavicle.
Suprasternal space is opened by transverse incision above sternum.
Platysma repair: Essential during neck surgery to prevent skin adherence and scarring.
Jugular veins: May be injured during tracheostomy or venesection.
External jugular vein distension: Indicates raised venous pressure (cardiac failure).
Infections of superficial fascia: Spread rapidly due to loose areolar tissue.
Definition: Condensed deep fascia forming supportive compartments of neck.
Layers:
Investing layer
Pretracheal fascia
Prevertebral fascia
Carotid sheath
Buccopharyngeal fascia
Pharyngobasilar fascia
Lies deep to platysma and surrounds the neck like a collar.
Attachments:
Superiorly → External occipital protuberance, superior nuchal line, mastoid, mandible.
Inferiorly → Spine of scapula, acromion, clavicle, manubrium sterni.
Posteriorly → Ligamentum nuchae and spine of C7.
Anteriorly → Symphysis menti and hyoid bone.
Encloses:
Muscles → Trapezius, Sternocleidomastoid.
Glands → Parotid and Submandibular.
Spaces → Suprasternal and Supraclavicular.
Suprasternal space (of Burns):
Lies above manubrium sterni.
Contains:
Sternal heads of SCM
Jugular venous arch
Lymph node
Interclavicular ligament
Parotid fascia (from investing layer) is dense → swelling is painful.
Submandibular gland enclosed between laminae → limits gland expansion.
Deep cervical fascia guides the spread of infections:
Pretracheal layer → may transmit infection to mediastinum.
Prevertebral layer → abscess may track into posterior mediastinum.
Surgical note: Platysma should be sutured separately to avoid visible scarring.
Lies deep to the platysma and surrounds the neck like a collar.
Forms the roof of anterior and posterior triangles of the neck.
Superiorly
External occipital protuberance
Superior nuchal line
Mastoid process and styloid process
External acoustic meatus
Base of mandible
Inferiorly
Spine of scapula
Acromion process
Clavicle
Manubrium sterni
Posteriorly
Ligamentum nuchae
Spine of 7th cervical vertebra
Anteriorly
Symphysis menti
Hyoid bone
Muscles:
Trapezius
Sternocleidomastoid (SCM)
Glands:
Parotid gland (forms parotid fascia — dense and unyielding)
Submandibular gland (forms capsule between laminae)
Spaces:
Suprasternal (of Burns) → contains:
Sternal heads of SCM
Jugular venous arch
Lymph node
Interclavicular ligament
Supraclavicular space → crossed by:
External jugular vein
Supraclavicular nerves
Lymphatics
Special Modifications:
Forms stylomandibular ligament between styloid process and mandible.
Forms parotidomasseteric fascia and pulleys for digastric and omohyoid tendons.
Painful parotid swelling: Dense parotid fascia prevents expansion.
Submandibular gland excision: External carotid artery must be secured before division; it lies near stylomandibular ligament.
External jugular vein injury: May cause air embolism because fascia fixes the vein open.
Surgical importance: Platysma must be sutured separately to prevent ugly scars
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.Thin fascial layer enclosing the thyroid gland and forming its false capsule.
Continuous above with buccopharyngeal fascia and laterally with carotid sheath.
Superiorly:
Hyoid bone (median plane)
Oblique line of thyroid cartilage (laterally)
Cricoid cartilage (more laterally)
Inferiorly:
Below thyroid gland → encloses inferior thyroid veins
Blends with fibrous pericardium and arch of aorta
Laterally:
Fuses with fascia deep to SCM, forming anterior wall of carotid sheath
Posterior part forms ligament of Berry (suspensory ligament of thyroid) attaching gland to cricoid cartilage.
Allows free movement of trachea during swallowing.
Infections anterior to fascia → may extend to anterior mediastinum.
Thyroid swellings move with deglutition because the gland is attached to laryngeal cartilages via Berry’s ligament.
Lies in front of vertebral column, covering prevertebral and scalene muscles.
Extends laterally as axillary sheath around brachial plexus and subclavian vessels.
Provides a fixed base for movements of pharynx, oesophagus, and carotid sheath.
Infections behind fascia: Commonly due to tuberculosis of cervical vertebrae (caries).
May produce retropharyngeal abscess, bulging into posterior pharyngeal wall.
Pus may extend laterally into posterior triangle or down into superior mediastinum.
Infections in front of fascia (retropharyngeal space):
From suppuration in retropharyngeal lymph nodes.
May form acute abscess and spread into posterior mediastinum
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.Condensation of fibroareolar tissue around main neck vessels.
Anterior wall: Formed by pretracheal fascia.
Posterior wall: Formed by prevertebral fascia.
Common or internal carotid artery
Internal jugular vein (thin fascial covering)
Vagus nerve (X cranial)
In upper part: Glossopharyngeal (IX), Accessory (XI), Hypoglossal (XII) nerves pierce it at different levels.
Ansa cervicalis – embedded in anterior wall.
Sympathetic chain – lies behind sheath on prevertebral fascia.
SCM – overlaps sheath superficially.
Fusion: Sheath fused with layers of deep cervical fascia.
Pathway for spread of infection between head, neck, and mediastinum.
Surgical importance: Awareness of relationship with internal jugular vein (lateral) and carotid artery (medial) is crucial in neck dissections or central line placement.
Thin outer covering of the pharynx, continuous above with pretracheal fascia.
Covers pharyngeal constrictor muscles externally and extends onto the buccinator muscle in front.
Forms part of the deep cervical fascia.
Superiorly: Base of the skull (around pharyngeal tubercle).
Inferiorly: Blends with pretracheal fascia over the larynx.
Laterally: Continuous with carotid sheath.
Anteriorly: Fuses with the fascia over buccinator muscle, forming pterygomandibular raphe.
Provides a smooth surface for movements of pharyngeal muscles during swallowing.
Serves as a barrier separating the pharyngeal wall from the retropharyngeal space.
Infection behind buccopharyngeal fascia → retropharyngeal abscess.
Alar fascia, a subdivision, divides the retropharyngeal space into:
Anterior (true) space
Posterior “dangerous” space (infection may descend to mediastinum).
A thick fibrous sheet forming the inner fibrous layer of the pharyngeal wall.
Lies deep to the pharyngeal muscles, giving structural support where muscles are deficient.
Superiorly:
Base of skull — petrous temporal bone, pharyngeal tubercle, and part of sphenoid (medial pterygoid plate).
Laterally:
Blends with buccinator at pterygomandibular raphe.
Inferiorly:
Blends with muscle fibers of superior constrictor.
Maintains rigidity of the pharyngeal wall.
Prevents collapse during swallowing.
Provides anchoring framework for constrictor muscles.
Weakening may lead to formation of pharyngeal diverticula (Zenker’s diverticulum) through Killian’s dehiscence (gap between inferior constrictor and cricopharyngeus).
There are two main fascial spaces around the pharynx:
Retropharyngeal Space
Lateral Pharyngeal (Parapharyngeal) Space
Boundaries:
Anterior: Buccopharyngeal fascia.
Posterior: Prevertebral fascia (with alar fascia dividing it).
Lateral: Carotid sheaths.
Superior: Base of skull.
Inferior: Continues down to posterior mediastinum.
Contents:
Retropharyngeal lymph nodes.
Loose areolar tissue.
Clinical Significance:
Infections here form retropharyngeal abscesses, causing:
Dysphagia
Airway obstruction
Bulging of posterior pharyngeal wall
Pus may spread into posterior mediastinum, hence called the “dangerous space of neck.”
Boundaries:
Medial: Buccopharyngeal fascia (pharynx).
Lateral: Mandible and medial pterygoid muscle.
Anterior: Pterygomandibular raphe.
Posterior: Carotid sheath and its contents.
Superior: Base of skull.
Inferior: Continuous with submandibular space.
Contents:
Part of parotid gland.
Internal carotid artery, internal jugular vein, and cranial nerves IX–XII.
Loose connective tissue.
Clinical Significance:
Deep neck infections can spread from tonsil or pharynx into this space.
Abscess may compress airway or great vessels.
Pathway for spread of parapharyngeal abscess → mediastinum.
| Feature | Retropharyngeal Space | Lateral Pharyngeal Space |
|---|---|---|
| Position | Behind pharynx | Beside pharynx |
| Boundaries | Between buccopharyngeal and prevertebral fascia | Between pharynx and parotid/mandible |
| Contents | Lymph nodes, loose tissue | Carotid sheath, cranial nerves IX–XII |
| Spread of infection | Posterior mediastinum | Mediastinum via vascular sheath |
| Common abscess | Retropharyngeal abscess |
Parapharyngeal abscess |
Large, superficial strap-like muscle of the neck.
Divides the neck into anterior and posterior triangles.
Supplied by the spinal part of the accessory nerve (cranial XI).
Sternal head — Tendinous, from the superolateral part of the front of manubrium sterni.
Clavicular head — Musculotendinous, from the medial one-third of the superior surface of clavicle.
Passes deep to sternal head.
Between the two heads lies the lesser supraclavicular fossa over the internal jugular vein.
Mastoid process (lateral surface) — by thick tendon.
Lateral half of superior nuchal line — by thin aponeurosis.
Motor: Spinal accessory nerve (XI).
Proprioceptive: Ventral rami of C2 and C3.
Branches from:
Superior thyroid artery
Suprascapular artery
Occipital artery (two branches)
Veins correspond to arteries.
Unilateral contraction:
Turns the chin to opposite side.
Tilts the head toward the same shoulder.
Bilateral contraction:
Flexes the neck forward (e.g., raising head from pillow).
Assists forced inspiration by elevating sternum and clavicle.
Torticollis (Wry Neck):
Deformity due to spasm/contracture of sternocleidomastoid.
Head → bent to one side; chin → points to opposite side.
Types:
Rheumatic – exposure to cold.
Reflex – inflamed cervical lymph nodes irritating accessory nerve.
Congenital – birth injury → intravascular clotting → fibrosis of muscle.
Triangular space behind sternocleidomastoid on each side of neck.
Roof formed by investing layer of deep cervical fascia.
Floor formed by prevertebral fascia covering deeper muscles.
Anterior: Posterior border of sternocleidomastoid.
Posterior: Anterior border of trapezius.
Inferior (base): Middle one-third of clavicle.
Apex: Union of SCM and trapezius near superior nuchal line.
Roof: Investing layer of deep cervical fascia.
Floor: Splenius capitis, levator scapulae, scalenes (ant., med., post.).
Divided by inferior belly of omohyoid into:
Occipital triangle (above).
Supraclavicular / subclavian triangle (below).
Arteries:
Third part of subclavian artery
Transverse cervical and suprascapular arteries
Branches of occipital artery
Veins:
External jugular vein
Transverse cervical vein
Nerves:
Accessory nerve (XI)
Branches of cervical plexus (C2–C4)
Roots and trunks of brachial plexus
Phrenic nerve (on scalenus anterior)
Ansa cervicalis
Lymph nodes:
Superficial and deep cervical nodes.
Reflect investing fascia along posterior border of SCM.
Identify external jugular vein, cutaneous nerves (great auricular, transverse cervical).
Accessory nerve crosses triangle from SCM → trapezius.
Locate inferior belly of omohyoid, transverse cervical, and suprascapular vessels.
Accessory nerve injury: during lymph-node biopsy → paralysis of trapezius → drooping shoulder.
External jugular vein: fixed to fascia → risk of air embolism if injured.
Infections: may spread via fascial planes into axilla or mediastinum.
Pulsating mass in supraclavicular fossa → aneurysm of subclavian artery.
Supraclavicular lymph nodes: enlarged in abdominal or thoracic malignancies (Virchow’s node).
The posterior triangle contains important vascular, neural, and lymphatic structures, divided according to their plane of depth.
Third part of subclavian artery — major artery of the lower triangle; gives off:
Transverse cervical artery
Suprascapular artery
Occipital artery — small branches crossing the upper part of the triangle.
External jugular vein (EJV) — lies superficially in roof; drains into subclavian vein.
Transverse cervical and suprascapular veins — accompany respective arteries and drain into EJV or subclavian vein.
Subclavian vein — lies anterior to scalenus anterior (usually outside the triangle).
Occipital vein — drains into EJV.
(A) Cranial nerve:
Spinal accessory nerve (XI):
Emerges from posterior border of sternocleidomastoid at its middle.
Crosses the posterior triangle superficially and enters trapezius.
Lies about 1–2 cm above Erb’s point (where cervical cutaneous nerves emerge).
(B) Cervical plexus (C2–C4):
Appears at posterior border of SCM at the midpoint (Erb’s point).
Its branches include:
Lesser occipital nerve (C2) — behind ear.
Great auricular nerve (C2, C3) — to parotid region and ear.
Transverse cervical nerve (C2, C3) — across neck.
Supraclavicular nerves (C3, C4) — to skin over clavicle and upper chest.
(C) Brachial plexus:
Roots and trunks of the plexus lie between scalenus anterior and medius muscles.
Suprascapular nerve (C5, C6) — passes laterally across triangle.
Nerve to subclavius (C5, C6) — small branch to subclavius muscle.
(D) Phrenic nerve:
Descends obliquely across scalenus anterior, deep to prevertebral fascia.
Lies in front of subclavian artery and behind subclavian vein.
Superficial cervical lymph nodes — along the external jugular vein.
Deep cervical lymph nodes — along the internal jugular vein (deep to SCM, continuous above and below).
From above downward:
Splenius capitis
Levator scapulae
Scalenus medius
Scalenus posterior (sometimes)
Inferior belly of omohyoid — divides the triangle into:
Upper occipital triangle
Lower supraclavicular (subclavian) triangle
Prevertebral fascia — forms the floor of both triangles.
Accessory nerve injury — during lymph-node biopsy or neck dissection → trapezius paralysis → shoulder droop.
External jugular vein injury — risk of air embolism due to its fixation to deep fascia.
Infection spread:
Through fascial planes → posterior mediastinum or axilla.
From tonsil or parotid → parapharyngeal space → posterior triangle.
Subclavian artery aneurysm — produces pulsatile swelling in lower triangle.
Enlarged supraclavicular lymph node (Virchow’s node):
Left-sided enlargement = sign of abdominal malignancy (especially gastric carcinoma).
Cervical rib or scalenus anticus syndrome:
Compression of subclavian artery or brachial plexus → pain, numbness in upper limb.
Mnemonic — “Stop Thinking Inside Art”
S → Sternocleidomastoid (anterior boundary)
T → Trapezius (posterior boundary)
I → Inferior — clavicle (base)
A → Apex — union of SCM and trapezius
Mnemonic — “I Prefer Smooth Layers”
I → Investing layer of deep cervical fascia (roof)
P → Platysma (in fascia)
S → Splenius capitis
L → Levator scapulae
(plus scalenus medius and sometimes posterior)
Mnemonic — “Never Ever Let A Surgeon Hurry”
N → Nerves (Accessory, cervical, brachial plexus)
E → External jugular vein
L → Lymph nodes (superficial and deep)
A → Arteries (Transverse cervical, Suprascapular, Subclavian)
S → Scalenes (floor muscles)
H → Head of omohyoid (dividing belly)
Mnemonic — “LGT Super” (appear at Erb’s point)
L → Lesser occipital nerve (C2)
G → Great auricular nerve (C2, C3)
T → Transverse cervical nerve (C2, C3)
Super → Supraclavicular nerves (C3, C4)
Mnemonic — “Some Lovely Scalenes”
S → Splenius capitis
L → Levator scapulae
S → Scalenus medius / posterior
Mnemonic — “Only Sun Shines”
O → Occipital triangle (upper)
S → Subclavian (supraclavicular) triangle (lower)
S → Separated by omohyoid (inferior belly)
Mnemonic — “Two Tiny Soldiers”
T → Transverse cervical artery
T → Thyrocervical trunk (branch)
S → Suprascapular artery
Posterior triangle lies between sternocleidomastoid and trapezius.
It is divided into occipital and supraclavicular triangles by the inferior belly of omohyoid.
Roof: Investing layer of deep cervical fascia.
Floor: Prevertebral fascia covering splenius capitis, levator scapulae, and scalene muscles.
Spinal accessory nerve (XI) is the most important nerve of this triangle.
Cervical plexus cutaneous branches emerge at the midpoint of posterior border of SCM (Erb’s point).
External jugular vein crosses the triangle superficially; drains into subclavian vein.
Brachial plexus roots and trunks occupy the floor of lower part of the triangle.
Phrenic nerve descends obliquely on scalenus anterior, deep to prevertebral fascia.
Lymph nodes:
Superficial nodes → along external jugular vein.
Deep nodes → along internal jugular vein.
Subclavian artery (3rd part) and suprascapular artery are key vessels in lower triangle.
Accessory nerve injury causes paralysis of trapezius → shoulder droop.
External jugular vein injury can cause air embolism due to its fixed opening in fascia.
Infections in the triangle can spread via fascial planes to axilla or mediastinum.
Left supraclavicular lymph node enlargement (Virchow’s node) suggests abdominal or thoracic malignancy.
Cervical rib may compress subclavian artery or brachial plexus, producing thoracic outlet syndrome.
Prevertebral fascia forms axillary sheath around subclavian vessels and brachial plexus.
Platysma lies superficial to investing fascia and must be sutured separately during neck surgery.
SCM acts bilaterally to flex the neck and unilaterally to turn the face to the opposite side.
Omohyoid acts as a landmark, not a functional divider, during neck dissections.
Explanation:
The spinal accessory nerve (cranial nerve XI) is vulnerable during posterior triangle surgery or lymph-node removal.
It supplies the trapezius and sternocleidomastoid.
Injury causes:
Weakness of shoulder elevation (trapezius paralysis).
Difficulty in abduction above 90° (loss of scapular rotation).
Shoulder droop and winging of scapula (trapezius type).
Clinical correlation: Common after radical neck dissection or biopsy of posterior cervical lymph nodes.
Explanation:
The external jugular vein is fixed to the investing layer of deep cervical fascia, keeping its lumen open.
If injured, negative intrathoracic pressure during inspiration sucks in air → air embolism.
Air travels to the right atrium, causing cardiac arrest.
Preventive measure:
Apply immediate pressure and lower patient’s head to raise venous pressure before ligation.
Explanation:
The third part of the subclavian artery lies in the lower (supraclavicular) triangle.
A subclavian aneurysm presents as a pulsatile mass here.
May compress brachial plexus → pain, paresthesia, or weakness in upper limb.
Diagnostic clue:
Pulse disappears on pressure above clavicle.
May produce bruit on auscultation.
Explanation:
Caused by fibrosis of sternocleidomastoid due to birth trauma or intrauterine malposition.
Results in:
Head tilted to affected side.
Chin rotated to opposite side.
Chronic cases → asymmetrical face and skull (plagiocephaly).
Treatment:
Physiotherapy or surgical release of SCM if fibrosis persists.
Explanation:
Left supraclavicular node (Virchow’s node) drains via thoracic duct, which collects lymph from most of the body below the diaphragm.
Enlargement indicates secondary metastasis from abdominal or thoracic malignancies (often stomach or pancreas).
Clinical sign:
Painless, firm swelling in left supraclavicular fossa — Troisier’s sign.
Explanation:
A cervical rib arises from C7 vertebra.
Compresses the subclavian artery and lower trunk of brachial plexus.
Symptoms:
Tingling/numbness in ulnar aspect of hand.
Weakness in grip.
Reduced radial pulse on arm elevation.
Condition: Thoracic outlet (scalenus anticus) syndrome.
Explanation:
The prevertebral fascia extends laterally as the axillary sheath.
Pus or infection beneath prevertebral fascia may track into the axilla, leading to deep abscesses around brachial plexus and axillary vessels.
Explanation:
Mastoiditis (infection of mastoid air cells) → pus spreads along upper fibers of sternocleidomastoid or occipital triangle.
May cause deep neck abscess or secondary thrombophlebitis of veins in the triangle.
Explanation:
Deep cervical fascia divides neck into compartments and potential spaces.
Infection may spread along these planes:
Pretracheal fascia → anterior mediastinum.
Prevertebral fascia → posterior mediastinum.
Carotid sheath → base of skull or mediastinum.
Determines direction, depth, and severity of deep neck infections.
It is the triangular area on the lateral side of the neck bounded by the sternocleidomastoid anteriorly, trapezius posteriorly, and clavicle inferiorly.
Because it lies posterior to the sternocleidomastoid, whereas the area anterior to it forms the anterior triangle.
Anterior: Posterior border of sternocleidomastoid
Posterior: Anterior border of trapezius
Base: Middle third of clavicle
Apex: Union of SCM and trapezius near superior nuchal line
Roof: Investing layer of deep cervical fascia and platysma
Floor: Prevertebral fascia covering splenius capitis, levator scapulae, and scalene muscles
The inferior belly of omohyoid, dividing it into:
Occipital triangle (upper)
Supraclavicular / subclavian triangle (lower)
Third part of subclavian artery
Transverse cervical artery
Suprascapular artery
Occipital artery branches
External jugular vein
Transverse cervical vein
Suprascapular vein
The spinal accessory nerve (cranial XI) — crosses the triangle superficially from SCM to trapezius.
The midpoint of the posterior border of the sternocleidomastoid, where four cutaneous branches of the cervical plexus emerge:
Lesser occipital (C2)
Great auricular (C2, C3)
Transverse cervical (C2, C3)
Supraclavicular (C3, C4)
Accessory nerve
Occipital artery and vein
Cervical plexus branches
Lymph nodes
Third part of subclavian artery
Subclavian vein (lower, anterior part)
Suprascapular and transverse cervical vessels
Brachial plexus trunks
Supraclavicular lymph nodes
From above downward:
Splenius capitis
Levator scapulae
Scalenus medius
Sometimes scalenus posterior
The investing layer of deep cervical fascia.
Superficial cervical nodes along external jugular vein
Deep cervical nodes along internal jugular vein (deep to SCM)
Paralysis of trapezius
Drooping of shoulder
Weakness of arm elevation beyond 90°
Wasting of upper back muscles
May cause air embolism, because the vein is tethered to fascia and remains open when cut.
Roots and trunks of brachial plexus lie between scalenus anterior and medius muscles.
The phrenic nerve (C3, C4, C5).
The spinal accessory nerve and external jugular vein.
Left supraclavicular lymph node in the posterior triangle.
Enlargement suggests secondary metastasis from abdominal malignancy, especially gastric carcinoma.
Because the prevertebral fascia continues laterally as the axillary sheath, providing a path for pus or infection.
It can be compressed against the first rib to control hemorrhage.
May be the site of aneurysm causing pulsatile supraclavicular swelling.
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular nerves
Acts as a landmark, dividing it into two triangles; its inferior belly lies within the posterior triangle.
The prevertebral fascia.
1. The posterior triangle of the neck is bounded anteriorly by:
a) Trapezius
b) Midline of neck
✅ c) Posterior border of sternocleidomastoid
d) Clavicle
2. The posterior boundary of the posterior triangle is formed by:
✅ a) Trapezius
b) Levator scapulae
c) Scalenus medius
d) Omohyoid
3. The base of the posterior triangle is formed by:
✅ a) Middle one-third of clavicle
b) Inferior belly of omohyoid
c) Subclavius muscle
d) Sternum
4. The roof of the posterior triangle is formed by:
✅ a) Investing layer of deep cervical fascia
b) Pretracheal fascia
c) Buccopharyngeal fascia
d) Pharyngobasilar fascia
5. The floor of the posterior triangle is formed by:
✅ a) Prevertebral fascia covering muscles
b) Pretracheal fascia
c) Investing fascia
d) Buccopharyngeal fascia
6. The posterior triangle is divided into two by:
✅ a) Inferior belly of omohyoid
b) Superior belly of omohyoid
c) Sternohyoid
d) Scalenus medius
7. The upper division of the posterior triangle is called:
✅ a) Occipital triangle
b) Supraclavicular triangle
c) Submandibular triangle
d) Carotid triangle
8. The lower division of the posterior triangle is called:
✅ a) Supraclavicular (subclavian) triangle
b) Occipital triangle
c) Muscular triangle
d) Carotid triangle
9. The spinal accessory nerve crosses which triangle?
✅ a) Posterior triangle
b) Submental triangle
c) Carotid triangle
d) Digastric triangle
10. The spinal accessory nerve supplies:
✅ a) Sternocleidomastoid and trapezius
b) Omohyoid and levator scapulae
c) Platysma and scalenus anterior
d) Sternohyoid and thyrohyoid
11. The external jugular vein pierces which fascia?
✅ a) Investing layer of deep cervical fascia
b) Prevertebral fascia
c) Pretracheal fascia
d) Buccopharyngeal fascia
12. Erb’s point (nerve point of neck) is located at:
✅ a) Middle of posterior border of SCM
b) Apex of posterior triangle
c) Upper part of SCM
d) Near the clavicle
13. The nerves emerging from Erb’s point are branches of:
✅ a) Cervical plexus (C2–C4)
b) Brachial plexus
c) Vagus nerve
d) Hypoglossal nerve
14. The cutaneous branches of cervical plexus appearing at Erb’s point are:
✅ a) Lesser occipital, great auricular, transverse cervical, supraclavicular
b) Facial, auriculotemporal, occipital, vagus
c) Accessory, hypoglossal, auricular, phrenic
d) None of the above
15. The phrenic nerve descends on which muscle?
✅ a) Scalenus anterior
b) Scalenus medius
c) Longus colli
d) Sternohyoid
16. The brachial plexus roots and trunks are located:
✅ a) Between scalenus anterior and medius
b) In front of scalenus anterior
c) Behind scalenus medius
d) Between longus colli and sternohyoid
17. Which artery lies in the lower part of posterior triangle?
✅ a) Third part of subclavian artery
b) Common carotid artery
c) Vertebral artery
d) Inferior thyroid artery
18. Which vein is superficial in the posterior triangle?
✅ a) External jugular vein
b) Internal jugular vein
c) Subclavian vein
d) Facial vein
19. Injury to the spinal accessory nerve produces:
✅ a) Drooping of shoulder due to trapezius paralysis
b) Winging of scapula due to serratus anterior paralysis
c) Loss of sensation on shoulder due to supraclavicular nerve damage
d) None of the above
20. A pulsating swelling in the supraclavicular fossa suggests:
✅ a) Subclavian artery aneurysm
b) Enlarged lymph node
c) Lipoma
d) Cystic hygroma
21. Which lymph node, when enlarged, indicates abdominal malignancy?
✅ a) Left supraclavicular (Virchow’s node)
b) Deep cervical node
c) Submental node
d) Parotid node
22. The fascia forming the axillary sheath is a continuation of:
✅ a) Prevertebral fascia
b) Investing fascia
c) Pretracheal fascia
d) Buccopharyngeal fascia
23. The prevertebral fascia extends laterally as:
✅ a) Axillary sheath
b) Carotid sheath
c) Pharyngobasilar fascia
d) Buccopharyngeal fascia
24. Which nerve may be injured during posterior cervical lymph node biopsy?
✅ a) Spinal accessory nerve
b) Hypoglossal nerve
c) Phrenic nerve
d) Suprascapular nerve
25. The external jugular vein is a tributary of:
✅ a) Subclavian vein
b) Internal jugular vein
c) Brachiocephalic vein
d) Facial vein
A triangular space on the lateral side of the neck, bounded by the sternocleidomastoid, trapezius, and clavicle.
Because it lies posterior to the sternocleidomastoid, as opposed to the anterior triangle in front of it.
Anterior: Posterior border of sternocleidomastoid
Posterior: Anterior border of trapezius
Inferior (base): Middle third of clavicle
Apex: Union of SCM and trapezius at superior nuchal line
Roof: Investing layer of deep cervical fascia + platysma
Floor: Prevertebral fascia covering splenius capitis, levator scapulae, and scalene muscles
The inferior belly of omohyoid:
Upper part: Occipital triangle
Lower part: Supraclavicular (subclavian) triangle
From above downward:
Splenius capitis
Levator scapulae
Scalenus medius
(Sometimes) Scalenus posterior
The investing layer of deep cervical fascia.
The spinal accessory nerve (cranial nerve XI).
Accessory nerve
Branches of cervical plexus
Occipital artery and vein
Lymph nodes
Third part of subclavian artery
Suprascapular artery
Branches and trunks of brachial plexus
Supraclavicular lymph nodes
The external jugular vein.
Into the subclavian vein.
Because the vein is fixed to the investing fascia, it may remain open when cut, leading to air embolism.
The midpoint of the posterior border of the sternocleidomastoid, where the cutaneous branches of cervical plexus emerge.
Lesser occipital (C2)
Great auricular (C2, C3)
Transverse cervical (C2, C3)
Supraclavicular (C3, C4)
Cutaneous branches (as above)
Phrenic nerve (on scalenus anterior)
Ansa cervicalis (loop in carotid sheath)
Roots and trunks of brachial plexus
Suprascapular nerve (C5, C6)
Nerve to subclavius (C5, C6)
Emerges from SCM’s posterior border (middle third)
Crosses the triangle obliquely
Enters trapezius near its anterior border
Paralysis of trapezius → shoulder droop
Difficulty in raising arm above horizontal
Wasting of upper back muscles
The sternocleidomastoid muscle.
Common site for lymph node biopsies
Contains vessels for venous access or ligation
Pathway for spread of infections
Location of subclavian artery aneurysm
Superficial cervical nodes (along EJV)
Deep cervical nodes (along internal jugular vein)
The left supraclavicular lymph node,
Enlargement suggests abdominal malignancy, commonly stomach cancer (Troisier’s sign).
Because the prevertebral fascia continues laterally as the axillary sheath, enclosing axillary vessels and brachial plexus.
The phrenic nerve descends obliquely on the anterior surface of scalenus anterior, deep to the prevertebral fascia.
Sternocleidomastoid
Trapezius
The third part of the subclavian artery.
The prevertebral fascia.
The investing layer of deep cervical fascia — it fixes the external jugular vein, making it prone to air embolism if cut.
It acts as a landmark, dividing the triangle, and maintains venous patency by tensing cervical fascia.
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