1. Muscles and regional anatomy of the head and neck and the back
Lecturer: Dr. M. Samsam
University of Central Florida, Orlando,
Pictures from Platzer atlas and textbook
of human anatomy and K. Moore anatomy
And Tortora principles of anatomy, 10th edition

2. Skull: 2 parts: Neurocranium Facial skeleton Neurocranium: 8 bones
Frontal X1
Parietal X2
Temporal X2
Occipital X1
Sphenoid X1
Ethmoid X1
Facial Skeleton:
14 bones
Maxilla X2
Nasal X2
Zygomatic X2
Lacrimal X2
Palatine X2
Inferior Nasal Conchae X2
Mandible X1
Vomer X1

3. Skull continued
**Fontanels in the skull are the unossified remnants of the membranes in newborns.
Major fontanels are: anterior (ossified within months), posterior,
mastoid and sphenoid which are ossified within 6 month or more

7. Lveolar
rocess
Mental
Foramen

9. Foraminae of the skull
and their contents:

10. Muscles of the head These are mimetic muscle: radiate into the skin
of the face and the head, and their contraction
causes displacement of the skin.
4 groups:
A- Muscles of the Scalp
B- Muscles in the region of eyelid
C- Muscles in the Nasal region
D- Muscle of the Mouth region
A- Muscles of the Scalp:
Epicranius Muscle: (Occipitofrontalis)
Has 2 bellies: Frontal (3), Occipital (2), and in
between, the Galea Aponeurotica (1).
Temporoparietalis M. (5)
Epicranius Function:
produces wrinkles in forehead and gives facial
expression of Astonishment.
Innervation: All mimetic muscles by Facial
nerve (cranial nerve CNVII) .

11. Muscles in the region of eyelid or palpebral fissure:
Orbicularis Oculi muscle:
Has 3 parts: Orbital (1), Palpebral (2) and
Lacrimal (3).
Function: produces folds in lateral angle of the
eye, expression of Worry and concern (C).
Corrugator supercilli (7):
Pulls the skin and eyebrow down and medially.
Produces vertical folds. Protects against light.
Pathetic pain muscle.
Thinker’s brow expression (D)
Innervation:
All mimetic muscles by Facial (CNVII) N.

12. Mimetic muscles in the region of the mouth 1- Orbicularis Oris M.:
Function: its contraction closes the mouth.
Strong contraction gives a sucking shape.
Expression of reserve (D).
2- Buccinator M.: Quadrilateral in shape.
Origin: mandible at 1st or 2nd molar region.
Forms the pterygomandibular raphe (3).
Extends to angle of the mouth and forms the
lateral wall of its vestibule.
Function: enables air to be blown out of the
mouth. Pulls angle of the mouth laterally.
Keeps the mucous membrane of the cheek
free of folds.
Contraction gives expression of satisfaction (E).

13. Mimetic muscles in the region of the mouth 4- Zygomaticus Major:
Origin: zygomatic bone.
Insertion: angle of mouth.
Function: lifts the corner of the mouth upward,
giving expression of laughter or pleasure (F).
5- Zygomaticus Minor:
Origin: zygomatic bone
Insertion: nasolabial groove.
6- Risorius: (laughing muscle)
Function: together woth zygomatic major it
produces the nasolabial folds.
Its contraction gives expression of Action (G).
7- Levator labii superioris:
Origin: Infraorbital margin to skin of upper lip.

14. Mimetic muscles in the region of the mouth 8- Lavator anguli oris:
It lifts the angle of the mouth,
Giving expression of self confidence (8).
9- Depressor anguli oris:
Function: pulls the angle of the mouth
downwards and produces expression of
sadness (I).
10- Depressor labii inferioris:
It pulls the lower lid down, giving expression
of perseverance (K).
11- Mentalis:
Produces: chin-lip furrow, giving expression of
doubt and indecision (L).
12- Platysma
All mimetic muscles are innervated
by facial N. (CNVII)

15. Muscles of Mastication:
Masseter (1), temporalis (2),
Lateral (3) and medial pterygoid (4)
***All Innervated by Mandibular nerve (CNV/3).
***Develop from 1st branchial arch.
CNV= cranial nerve 5 (trigeminal nerve).
It has 3 branches: ophthalmic, maxillary
and mandibular
1- Masseter M:
Origin: Zygomatic arch (5)
Insertion: masseteric tuberosity of mandible (6)
Has 2 parts:
7- Superficial part (oblique fibers)
8- Deep part (vertical fibers)
Function: powerfully closes the jaw by elevating
the mandible. NN: Masseteric N CNV/3.
2- Temporalis M:
Origin: temporal fossa (9) as far as inf temp line.
Insertion: by a strong tendon to coronoid
process of mandible and mandibular ramus (11).
Function: strongest elevator of lower jaw.
NN: deep temporal N CNV/3.

16. Muscles of Mastication:
Masseter (1), temporalis (2),
Lateral (3) and medial pterygoid (4)
Lateral pterygoid M (3):
Has 2 parts (12 and 14)
Function: mandibular movements (guiding muscle).
NN: lateral pterygoid N CNV/3.
Medial Pterygoid M (4):
Runs at right angles to the lateral pterygoid M.
Has 2 parts
Angle of mandible is between this muscle and
the masseter M.
Function: elevates mandible and
pushes it forward. Rotational movement.
NN; Medial pterygoid N CNV/3.

17. Anterior Facial Regions:
First of all, the blood supply of the face is
mostly by ext. carotid and partly by int. carotid.
Facial artery (2) from ext. carotid passes
it anastomose with dorsal nasal A. (4) coming
from Ophthalmic A.
Forehead is supplied by supratrochlear A. (8)
and supraorbital (9) A., both from ophthalmic A.
Facial vein (10) anastomoses via Angular
vein (11) With dorsal nasal vein.
***This anastomoses is extremely important
since this allows a direct connection to
Cavernous sinus, through which, infections
eg: from a furuncle on the lip, may get into skull.
All mimetic muscles are innervated by branches
of facial N: 13- temporal branch, 14- zygomatic
15- buccal branch and 16- marginal mandibular.

18. Anterior Facial Regions:
Sensory innervation to the face:
Is derived from branches of
Trigeminal (V) nerve: Ophthalmic (V/1),
Maxillary (V/2) and mandibular (V/3) nerves.
Ophthalmic nerve: supplies the forehead:
Supratrochlear N (17) and supraorbital (18).
Maxillary nerve: supplies lower eyelid,
Cheek, lateral nasal, upper lip and anterior
Temporal regions by Infraorbital N. (22).
Mandibular N: lower lip over mandible
(not angle) and chin by mental N (23).
Auriculotemporal N (24) supplies skin on
Mandible ramus, concha of auricle and
Most part of ext. layer of tympanic memb.
Sensitivity of the 3 branches of trigeminal N
can be tested by pressing nerves 18, 22 and 23.
This is a vertical line, 2-3 cm lateral to midline.
***Trigeminal Neuralgia.

19. Trigeminal neuralgia (Tic Douloureux)
A disorder of unknown etiology (cause) associated with intractable pain along the 3
branches of trigeminal nerve but especially along maxillary and mandibular
nerves. A simple trigger such as touch, cold or hot can start the pain.
Therapy: Carbamazepine, radiofrequency destruction of the
branches involved.
Alcohol or Glycerin injection around the trigeminal ganglion.
Transection of the sensory root.
Vascular decompression of the trigeminal ganglion.

20. Hyoid bone: Is in the neck, but, may be included with the bony
skeleton of the skull.
PARTS:
Body (anterior)
Greater horns (laterally)
Lesser horns (upwards)
Stylohyoid ligament

21. Muscles of the neck: Platysma: Is the only cutaneous
muscle in human body
(under the skin)
Attachments: superiorly: inf. border
of mandible and skin, and is attached
to superficial fascia covering pectoralis
major and deltoid muscles inferiorly.
*Action: brings down corners of the
mouth, expressing sadness.
*Innervation: Facial N. (VII)
(cervical branch)
*Injury to this nerve leads to
paralysis of platysma (skin falls
away from the neck by folds).
*Careful sutures of the skin should be
made in surgery of the neck region.

22. Cranial muscle inserted on the Shoulder girdle:
1- Trapezius M: Repetition: 2- Descending part
3- Transverse part, 4- Ascending part
Descending:
Origin: from external occipital protuberance
Superior nuchal line, and Ligamentum nuchae
Insertion: lateral third of clavicle
Transverse part: from C7-T3 spinous process
Inserted to: clavicle and scapula (acromion)
Ascending: from T3-T12 spinous process
Insertion: spine of the scapula
*Function: elevation, retraction and
rotation of scapula.
Helps in adduction and slight elevation of arm
*Innervation: spinal root of Accessory nerve
(CNXI) and C3-C4 (propioception)
14- Sternocleidomastoid M
Origin: sternum (15) and clavicle (16)
Insertion: Mastoid process and sup. nuchal line
Function: unilateral contraction turns the head
to opposite side and bends it ipsilaterally.
Bilateral contraction: lifts the head.
Also functions in respiration.
Innervation: Accessory nerve (CNXI) and C2-C3

23. **Accessory nerve Examination

24. **Congenital and Spasmodic Torticollis (Wry neck)
Congenital Torticollis:
Most common type of Torticollis.
Fibromatosis (fibrous tissue tumor)
of Sternocleidomastoid M.
Head turns to the side and face away
from the affected side.
Leads to stifness of the neck due to fibrosis
and shortening of the sternocleidomastoid.
Injury during delivery may also result in Torticollis.
(muscle tear and hematoma leads to fibrosis)
Therapy: division of the muscle below XI nerve
or from its distal attachment.

25. **Spasmodic Torticollis (Wry neck)
Cranial dystonia (abnormal tonicity)
Between years of age. Unknown cause.
May involve bilateral neck muscles especially
the Sternocleidomastoid M.
Unilateral deviation of the head.
(turning, tilting, flexion or extension of the neck)
May involve other muscles in the body.
Therapy: myotomy or also section of the spinal
Accessory N. and upper cervical ant. roots

26. **Infrahyoid muscles:
Omohyoid, Sternohyoid,
Sternothyroid and Thyrohyoid
*2-4) Omohyoid muscle
Has an Inferior and a superior belly
Inf. Belly:
Origin: Upper border of scapula near
the scapular notch.
Sup. Belly: inserted to the lower border of
the body of the Hyoid bone.
A fascial sling connects it to the clavicle.
*Action: fascia tensor and dilates internal
Jugular vein lying beneath it.
(this aids to return of blood to the heart)
Opens the mouth and helps in lateral
flexion of the head.
*Innervation: Most Infrahyoid muscles are
innervated by cervical Ansa (C1-C3).

27. Infrahyoid muscles: Continued
1-3) Sternohyoid M.:
Origin: Post. Surface of manubrium and
Sterno-clavicular joint
Insertion: Body of hyoid bone (inner surface
and laterally).
4-6) Omohyoid M.
7-9) Sternothyroid: deeper to sternohyoid
Origin: post. Surface of manubrium
Insertion: oblique line of thyroid cartilage
It covers the thyroid gland.
10-11) Thyrohyoid M.:
Continuation of Sternothyroid M.
Origin: oblique line of thyroid cartilage
Insertion: inner surface of body (laterally)
and lower margin of greater horn.
Innervation: C1, before giving the branch to
cervical ansa.
*Action: All infrathyroid muscles work together
to approximate thyroid cartilage to hyoid bone.
When mouth is open, they stabilize
laryngeal cartilages and the hyoid bone.

28. Suprahyoid muscles: **Digastric M.: Origin: Insertion: Stylohyoid M.:
Digastric, Stylohyoid,
Myelohyoid and Geniohyoid MM.
**Digastric M.:
Origin:
Anterior belly: from mandible
Posterior belly:
Mastoid notch of temporal bone
Insertion:
intermediate tendon to body and
greater horn of hyoid bone.
Function: Raising hyoid and
stabilizing it in speaking and
swallowing,depressing the mandible.
**Innervation:
Ant. Belly: V/3, trigeminal N. (from nerve to
myelohyoid) and post. belly: VII, facial nerve.
Stylohyoid M.:
Origin: Styloid process of temporal bone
Insertion: body of hyoid
Function: elevates and retracts hyoid bone,
elongates floor of the mouth.
Innervation: VII, facial N. (cervical branch)

29. Suprahyoid muscles: *Myelohyoid M.: *Geniohyoid M.:
continued
Myelohyoid, Geniohyoid,
Stylohyoid and
Digastric muscles.
*Myelohyoid M.:
Origin: mandible,
Insertion: body of hyoid
Function:
Elevates hyoid and floor of the
mouth and tongue in swallowing
and speaking.
*Innervation:
V/3 (myelohyoid N. from
inf. Alveolar N.)
*Geniohyoid M.:
Origin: mandible, Insertion: body of hyoid
Function: pulls the hyoid anterosuperiorly,
shortens floor of the mouth and widens pharynx.
*Innervation: C1 via hypoglossal nerve

30. Atlas: Submandibular region:
Look at the relation between Hyoglossus and Myelohyoid Muscles,
the Lingual nerve, Submandibular gland, duct, and
ganglion and the Hypoglossal nerve

31. Atlas: 12- Geniohyoid M. 10- Myelohyoid M.
15- Ant. Belly of Digastric M.
14- Genioglossus (cut)

32. Atlas: 2- Hyoglossus 8- Geniohyoid 9- Myelohyoid
10- Ant. Belly of Digastric
5- Stylohyoideus
4- Styloglossus
1- Genioglossus

33. Paravertebral and Scalene muscles Paravertebrals:
Rectus Capitis Ant., Logus Capitis and
Longus Colli.
Rectus capitis: (1-3)
Helps to flex the head. NN: Cervical Plex.(C1)
Longus Capitis: (4-6)
Bend the head forward and unilateral action
turns the head sideways.
NN: Cervical Plexus(C1-4).
Longus Colli: (7, 8, 9)
Action: unilateral contraction bends and turns
cervical column to the side.
Also bend the cervical spine forwards.
NN: cervical and brachial Pl. (C2-C8)

34. Scalene muscles Most important muscles for quiet inspiration
They lift the first 2 pairs of ribs (sup part of thorax).
Unilateral contraction tilts cervical column to one
side.
Scalene Anterior (17):
Scalene Medius (20):
Scalene Posterior (23):
NN: Brachial plexus (C4-C8).
Scalenus minimus M. may be present in 30%.
26- Scalene opening:
brachial plexus and subclavian artery pass through.

35. Occipital (Omotrapezoid) triangle: Floor: Splenius Capitis (17),
Lavator Scapulae (16), Post. Scalene (15)
and Middle Scalene (14).
*Content: Cervical Plexus.
Accessory Nerve comes from behind the
Sternocleidomastoid M.
It divides the supraclavicular region to a
Care free and careful zone.
12- superficial cervical Artery
13- Anterior Scalene M.
***Scalene gap:
Formed between scalene Anterior and Middle
and 1st rib, in which run the Brachial plexus (18)
and Subclavian Artery (19).
21- Phrenic nerve Suprascapular N.
23- Long Thoracic N Dorsal Scapular N.
25- Cervical lymph node A A

36. Cervical Plexus: Atlas, only look 1- anterior rectus capitis
2- Lateral rectus capitis
3- Longus Colli
4- Ant. Scalene M.
5- Middle Scalene M.
6- Deep Ansa Cervicalis
7- Hypoglossal nerve
8- upper root of cervical ansa
9- Thyrohyoid muscle
10- Inf. root of cervical ansa
11- Omohyoid M.
12- Sternothyroid M.
13- Sternohyoid M.
15- Lesser Occipital N.
16- Greater auricular N.
17- Transverse Cervical N.
18- Supraclavicular nerves
19- Phrenic nerve.

37. Triangles of the Neck: Anterior Triangle: Posterior Triangle:
Submandibular T.
Carotid T.
Muscular T.
Submental T.
Borders:
Posterior (lateral) :
Sternocleidomastoid
Superior: mandible
Anterior: midline of the neck
Posterior Triangle:
Occipital T.
Omoclavicular T.

38. Carotid Triangle: Borders: Content: Super: Post. belly of Digastric
Med: Sup. Belly of Omohyoid
(2)
Lat: Sternocleidomastoid (1)
Skin innervat.: cervical plexus
Content:
External jugular vein and
Superficial cervical fascia
Internal jugular vein (9) and
Common facial vein (6)
Common carotid A. (10)
Carotid Sinus (11)
12- Internal carotid A.
13- External carotid A.
29- Vagus nerve (behind and in
between vessels)
24- descending branch of XII
(upper root of cervical ansa)
runs above the carotid sheath.
18- Hypoglossal N.

39. Big vessels in the neck:
Hypoglossal nerve
External Carotid A.
Common
Carotid A.
internal Jugular V.
Vagus N.
Subclavian A.
Brachial plexus
Common facial V.
Superior cervical
sympathetic ganglion

40. Internal jugular vein puncture:

41. Thyroid Gland: Body's largest endocrine gland
Is deep to sternothyroid and sternohyoid M
At C5-T1 level. It has a capsule
and externally covered by a sheath.
Consists of an isthmus (1), which
unites the lobes.
A right lobe (2) and a left lobe (3).
Pyramidal lobe:
A remnant of thyroglossal duct
may persist in the middle part
of thyroid (50%).
Ectopic Thyroid
****Function:
Produces Thyroxin which controls
the rate of metabolism of the body,
and Calcitonin controlling Ca++
metabolism.
Blood supply:
Superior (8) and inferior (9) thyroidal artery

42. Goiter: Enlargement of Thyroid gland (nonneoplastic
and noninflammatory). Usually not upward shift.
Endemic in areas deficient in Iodine in food.
Swelling in the neck which may disturb trachea,
esophagus and/or laryngeal nerves.
Exophthalmic goiter is due to excessive production
of thyroxin.
Thyroidectomy:
Removal of thyroid due to cancer.
Subtotal due to preservation of Parathyroid glands
and recurrent as well as superior laryngeal nerves.
Inadvertent removal of parathyroid glands lead to
tetany, severe convulsion and muscle spasm due to
decrease in serum Ca++ and may lead to immediate
respiratory failure.

43. Usually 4, one upper and one lower gland per each thyroid lobe.
Parathyroid glands:
Usually 4, one upper and one lower gland per each thyroid lobe.
They are external to thyroid capsule and internal to the connective tissue sheath.
Function: Produce parahormon, controlling the metabolism of P and Ca++.