To MBBS 2nd yearDr. Laxman Khanal

Assistant professor, department of Anatomy, BPKIHSDate:07-02-2017

Anterior Triangles of

Neck

Q. Which side of SCM muscle is in action ?a. Rightb. Leftc. Both

Q. Identify the muscle.

SternoCleido

Mastoid

Compartments of neck region

1. Visceral 2. Vertebral3. Neurovascular

Cut throat wounds normally escape the injury to vesselsbecause they become pushed back in deeper plane involuntary extension of neck.

Subcutaneous structures of neck

•Triangular gap betweenthe two heads of SCMis called lessersupraclavicularfossa.•It contains the terminalpart of the IJV, which canbe entered at this site by aneedle or catheter.

Nerve supplySpinal accessory nerve Branch from C2 and C3

Function of right SCM• Same side lateral flexion• Opposite head rotation

Function of Bilateral SCM

Anterior triangle of neck

Division of anterior triangle

1.Digastric triangle2.Carotid triangle3.Muscular triangle4.Submental triangle

Fascial sling (investing layer)

Roof

Floor

Room

Investing layer of deep cervical fascia

Muscles

1. Submental2. Digastric3. Muscular4. Carotid

• What forms the walls?• Who resides in the room?

+Bones (H +M)Midline of neck

Contents

Submental triangle•Boundaries•Floor •Contents-Submental LN -Submental vein-Ant jugular vein

Triangle mostly occupied by lymph node.

Boundaries Contents-Infrahyoid muscles1. Sternohyod and

Omohyoid2. Sternothyroid and

Thyrodyoid- Thyroid gland- Trachea- Esophagus

Muscular triangleWith no named vessels.

Attachment of infra-hyoid musclesOmo-Hyoid/Sterno-HyoidThyro-Hyoid/Sterno-Thyroid

# TOSS

• All except T are supplied by Ansa Cervicalis (C1 to C3).

• T supplied by C1 through hypoglossal nerve.

Ansa Cervicalis lies in carotid trianglebut supplies muscular triangle.

Suprahyoid muscles1. Geniohyoid2. Mylohyoid3. Digastric4. Stylohyoid

Location-digastric and submental (suprahyoid region).

Muscle of anterior neckSuprahyoid-submental and digastric Infrahyoid- muscular

Carotid triangleBoundariesFloor-Middle constrictor-Thyrohyoid membrane-Inferior constrictorContents

CCAICA &ECAfive branches of ECA

Vagus nerveSup laryngeal branch

Spinal accessory nerveHypoglossal nerveIJVCommon facial veinLingual veinAscending pharyngeal veinCCA, IJV, 10 /11 /12 CN

ContentsCCAICAECALower five branchesVagus nerveSup laryngeal branchSpinal accessory nerveHypoglossal nerveIJVCommon facial veinLingual veinAscending pharyngeal vein

1. Carotid sheath2. External CA3. 11th CN4. 12th CN

Artery- Carotid systemVein- IJVNerve- 10/11/12 nerve

1. Ascending pharyngeal artery2. Sup thyroid artery3. Lingual artery4. Facial artery5. Occipital artery6. Posterior auricular artery7. Maxillary artery8. Superficial temporal artery

Ext carotid artery

Sup belly of omohyoid

Post belly of digastic

SCM

1. Anterior2. Posterior3. Medial4. Terminal

Carotid sinus Syndrome

NTS

Sudden rotation of headTight collar

IXth CNXth CN

• Decrease BP• Bradycardia• Vasodilation

Pressure

Sympathetic

Heart Vessels

Rare cause of Syncope or sudden death

Artery- Carotid systemVein- IJVNerve- 10/11/12 nerve

T O S S

Digastric triangleBoundariesFloor-Mylohyoid-Hyoglosus-Midle constrictorContentsAnterior part1. Superficial to mylohyoid2. Superficial to hyoglossusPosterior parts

ContentsAnterior part1. Superficial to mylohyoid2. Superficial to hyoglossusPosterior parts

Imp QnsWhat are the strs superficial to mylohyoid ?What are the strs superficial to hyoglossus ?

Posterior part of Digastric triangle

Lower part of parotidECAICAIJVVagus nerve

Superficial to mylohyoid1. Superficial part of submandibular gland

(facial artery and vein)1. Submental artery2. Mylohyoid Nerve3. Mylohyoid vessels

Relationship of Hyoglossusmuscle

• Deep part of SM gland• Duct of SM gland• SM ganglion• Lingual nerve• Hypoglossal nerve• Vena comitantes

• Stylohyoid ligament• IX th nerve• Lingual artery

Superficial to Hyoglossus• Deep part of submandibular gland • Submandibular duct• Hypoglossal and Lingual nerve• Submandimular ganglion• Styloglossus muscle

?????

• Anterior neck contains two groups of muscles.

1. Supra hyoid

2. Infra hyoid

• Carotid system, IJV and CN (X, XI & XII) pass through carotid triangle.

• Ansa cervicalis lies anterior to carotid sheath and supplies infrahyoid muscles except Thyrohyoid.