SUBOCCIPITAL TRIANGLE

SUBOCCIPITAL TRIANGLE: These are a pair of muscular triangles situated on each side of the midline in the suboccipital region. BOUNDARIES: Supero-medially : Rectus capitis posterior major Supero-laterally : Obliquus capitis superior Inferiorly : Obliquus capitis inferior

Roof: Medially : Dense fibrous tissue covered by the semispinalis capitis Laterally : By the longissimus capitis and occassionally the splenius capitis Splenius capitis Semispinalis capitis Longissimus capitis

FLOOR: Formed by the posterior arch of atlas and posterior atlanto-occipital membrane Posterior arch of atlas Posterior atlanto-occipital membrane

Contents: - First cervical nerve (suboccipital nerve) - Third part of vertebral artery - First cervical nerve (suboccipital nerve) - Suboccipital plexus of veins Third part of vertebral artery First cervical nerve(C1)

Clinical importance: Cisternal puncture is done when lumbar puncture fails to collect the Cerebro spinal fluid. (C.S.F)

SIDE OF THE NECK

Side of the neck is roughly quadrilateral in outline. It is bounded: Anteriorly : By the Anterior midline Posteriorly : By the anterior border of Trapezius Superiorly : By the base of the mandible and line joining the angle of the mandible to the mastoid process and superior nuchal line Inferiorly : By the clavicle. This quadrilateral space is divided obliquely by the sternocleidomastoid muscle into the Anterior and Posterior traingle

The side of neck is covered from outside to inside by 1) Skin 2) Superficial fascia and 3) Deep fascia Skin: The skin of neck is supplied by the 2nd, 3rd and 4th cervical nerves. The anterolateral part of the skin is supplied by -- Anterior primary rami of anterior cutaneous, Great auricular Lesser occipital and Supraclavicular nerves

------ Investing layer ------ Prevertebral layer DEEP FASCIA: The deep fascia of neck is condensed to form the following layers: ------ Investing layer ------ Prevertebral layer ------ Pretracheal layer ------ Carotid sheath

Posterior Triangle of Neck

Situation: It is Situated just behind the Stenocleidomastoid muscle. Boundaries: Infront: Posterior border of Sternocleidomastoid Behind: Anterior border of Trapezius

Inferior/base : Middle 1/3rd of the clavicle. Apex : Superior nuchal line of occipital bone where sternocleidomastoid and trapezius meets.

Roof: It is formed from outside to inside by the 1) Skin 2) Superficial fascia: It contains MUSCLE VEIN ARTERIES NERVES Platysma External jugular vein Arteries derived from Occipital Transverse cervical Suprascapular Supraclavicular Lesser occipital Great auricular 3) Investing layer of deep cervical fascia

Floor: It is formed by the following muscles: Semispinalis capitis Splenius capitis Levator scapulae Scalenus posterior Scalenus medius Scalenus anterior (sometimes) and First digitation of the serratus anterior All these muscles are covered by prevertebral layer of deep cervical fascia,

Divisions of Posterior triangle: The triangle is subdivided by the inferior belly of the omohyoid into: The upper larger part called occipital triangle Lower smaller part called the supraclavicular triangle Occipital triangle Inferior belly of the omohyoid Supraclavicular triangle

Contents of occipital triangle: Spinal part of accessory nerve: It appears in the posterior triangle deep to mid point of the posterior border of the sternocleidomastoid and passes between roof and floor of the triangle resting on levator scapulae and disappears under cover of trapezius. Levator scapulae Spinal part of Accessory nerve

2) 3rd and 4th cervical nerves: It provides muscular branches to levator scapulae and trapezius muscle Accessory nerve 3rd cervical nerve 4th cervical nerve

3) Dorsal scapular nerve: Arises from the C5 root of brachial plexus and supplies rhomboideus muscles Dorsal scapualr nerve

4) Transverse cervical artery: Branch of Thyrocervical trunk of Subclavian artery Transverse cervical artery Thyrocervical trunk

5) Four cutaneous branches: a) Lesser occipital nerve (C2) b) Great auricular nerve (C2, C3) c) Transverse cervical nerve (C2, C3) d) Supraclavicular nerve (C3, C4) Transverse cervical nerve (C2, C3) Lesser occipital nerve (C2) Great auricular nerve (C2, C3) Supraclavicular nerve (C3, C4)

3 2 1 Contents of supraclavicular triangle: Third part of subclavian artery and vein Suprascapular artery and vein Transverse cervical artery and vein Terminal part of external jugular vein 3 2 1

a d b 5) Trunks of brachial plexus : a) Dorsal scapular nerve b) Long thoracic nerve c) Nerve to subclavius d) Suprascapular nerve a d b

ANTERIOR TRIANGLE OF THE NECK

Boundaries of triangle: Anteriorly : Median plane Posteriorly : By the sternocleidomastoid muscle Superiorly : By the base of the mandible, and by the line joining the angle of the mandible to the mastoid process Apex : It lies above the manubrium sterni Sternocleidomastoid Median plane

The triangle encloses four Suprahyoid and four Infrahyoid muscles A) Suprahyoid muscles : Digastric Stylohyoid Mylohyoid Geniohyoid

B) Infrahyoid muscles: 3) Thyrohyoid 1) Sternohyoid 2) omohyoid 4) Sternothyroid

Subdivisions of the triangle: The triangle is subdivided by the Digastric muscle and the superior belly of omohyoid into: 1) Submental triangle 2) Digastric triangle 3) Carotid triangle 4) Muscular triangle 2 1 4 3

Submental triangle: It is a median triangle Boundaries of the triangle: On each side: Anterior belly of corresponding digastric muscle Base : Body of hyoid bone Apex : Lies at the chin Floor : Formed by right and left Mylohyoid muscles and the median raphe uniting them. Anterior belly of digastric Mylohyoid Hyoid bone

Contents: 2-4 small submental lymph nodes situated in the superficial fascia between the anterior bellies of the digastric muscles. Small submental veins join to form the anterior jugular vein.

Anterior belly of digastric 2) Digastric triangle: Boundaries of digastric triangle: Above: Lower border of the body of the mandible and a line extending fro the angle of mandible to the mastoid process Below and behind: Posterior belly of digastric and stylohyoid muscles. Below and Infront: Anterior belly of digastric Posterior belly of digastric Anterior belly of digastric Stylohyoid

Cervical branch of facial nerve Transverse cutaneous nerve of neck Roof: 1) Skin 2) Superficial fascia containing: The platysma, Cervical branch of facial nerve, The ascending branch of the transverse cutaneous nerve of the neck. Cervical branch of facial nerve Transverse cutaneous nerve of neck Platysma

Middle constrictor muscle 3) Deep fascia : It splits to enclose the submandibular salivary gland Floor: Anteriorly: It is formed by the Mylohyoid muscle Posteriorly: By the Hyoglossus muscle A part of middle constrictor muscle also appears in the floor Middle constrictor muscle Mylohyoid muscle Hyoglossus muscle

Submandibular salivary gland Submandibular lymph node Contents: 1) Anterior part of the triangle: Superficial part of the submandibular salivary gland. The facial vein and submandibular lymph nodes, superficial to the gland and facial artery lies deep to gland Submental artery Mylohyoid vessels and nerve And part of hypoglossal nerve. Submandibular salivary gland Facial vein Submandibular lymph node Facial artery

2) Posterior part of the triangle: a) Lower part of the parotid gland. b) External carotid artery before it enters the parotid gland. c) Carotid sheath containing internal carotid artery, internal jugular vein and vagus nerve. Internal Carotid Artery External carotid artery Internal jugular vein

Posterior belly of digastric Superior belly of omohyoid 3) Carotid triangle: It contains all the large vessels and nerves of the neck Boundaries: Superiorly: Posterior belly of digastric and Stylohyoid muscle Infront and below: Superior belly of omohyoid Posteriorly: Anterior border of the sternocleidomastoid muscle Posterior belly of digastric Carotid triangle Superior belly of omohyoid Sternocleidomastoid

Cervical branch of facial nerve Transverse cutaneous nerve of neck Roof: 1) Skin 2) Superficial fascia containing: It contains a) Platysma b) Cervical branch of facial nerve c) The transverse cutaneous nerve of neck Cervical branch of facial nerve Transverse cutaneous nerve of neck Platysma

3) Investing layer of deep cervical fascia Floor : It is formed by a) Thyrohyoid muscle b) Hyoglossus c) Middle and inferior constrictors of the pharynx Hyoglossus Middle constrictor Inferior constrictor Thyrohyoid muscle

Contents: A) Arteries: 1) Common carotid artery and its divisions. 2) External carotid artery and its branches. Internal carotid artery External carotid artery Common carotid artery

B) Veins: 1) Internal jugular vein 2) Common facial vein 3) Pharyngeal vein 4) Lingual vein Internal jugular vein Common facial / Internal jugular vein Common facial vein Lingual vein Internal jugular vein

s v H C) Nerves: 1) Vagus running vertically downwards 2) Superior laryngeal Internal and External laryngeal nerve 3) Spinal accessory 4) Hypoglossal nerve 5) Sympathetic chain H s v

Internal & External laryngeal branches of Superior laryngeal Vagus

D) Carotid sheath with its contents E) Lymph nodes: Jugulo-digastric and Jugulo-omohyoid lymph nodes Jugulo-digastric Jugulo-omohyoid

D) Muscular triangle: Boundaries: Infront: Anterior median line of the neck from the hyoid bone to sternum. Behind and above: Superior belly of omohyoid muscle Behind and below: Anterior border of sternocleidomastoid. Superior belly of omohyoid Sternocleidomastoid Muscular triangle

Supplied by Ventral rami of spinal nerves C1, C2, C3. Contents: Infrahyoid muscles are chief contents of the triangle Sternohyoid Sternothyroid Thyrohyoid Omohyoid Supplied by Ventral rami of spinal nerves C1, C2, C3.

FACE

Extent of the face: Superiorly : It extends upto hair line Inferiorly : To the chin and the base of the mandible On each side: To the auricle

Skin: Superficial fascia: It is very vascular It is rich in sebaceous and sweat glands . Sebaceous glands keeps the face oily and sweat glands regulates the body temparature. It is very elastic and thick because facial muscles are inserted into it. Superficial fascia: It contains: 1) Facial muscles, all of which are inserted into the skin 2) The vessels and nerves 3) Variable amount of fat

Deep fascia: It is absent , except over parotid gland where it forms the parotid fascia, and over the buccinator where it forms the Buccopharyngeal fascia.

Facial muscles: The Facial muscles are the subcutaneous muscles and bring about differential facial expression.

Topographically, the muscles are grouped as follows: A) Muscles of scalp: Occipofrontalis Occipofrontalis

B) Muscles of auricle: Around the ear AURICULARIS SUPERIOR AURICULARIS ANTERIOR AURICULARIS POSTERIOR

C) Muscles of the eyelids: Orbicularis oculi Corrugator supercilli Levator palpebrae superioris 1 3 2

1 2 3 4 D) Muscles of nose: Procerus Compressor naris Dilator naris Depressor septi 1 2 3 4

4 1 E) Muscles around the mouth: Orbicularis oris Levator labii superioris alaequae nasi Levator labii superioris Levator anguli oris Zygomaticus minor Zygomaticus major 4 1

11 10 7 8 9 E) Muscles around the mouth: 7) Depressor anguli oris 8) Depressor labii inferioris 9) Mentalis 10) Risorius 11) Buccinator 11 10 7 8 9

F) Muscles of neck: Platysma Platysma

Name of the Muscle Expression Muscles producing facial expression : Name of the Muscle Expression Zygomatics Major Smiling & Laughing Levator Labii Superioris & Levator Anguli Oris Sadness Depressor Anguli Oris Grief Dilator Naris & Depressor Septi Anger Corrugator Supercilli & Procerus Frowning Frontalis Surprise Mentalis Doubt Risorius Grinning Zymaticus Minor Contempt

Blood supply: Arterial supply: Venous drianage: It is supplied by Facial artery and Transverse facial artery. Venous drianage: The veins accompany the arteries and drains into common facial and retromadibular vein.

Motor nerve supply of face comes from ‘terminal branches of facial nerve’ Sensory Nerve Supply: Sensory nerve supply of face comes from ‘trigeminal nerve’

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