Muscles Of The Neck

Question 1

What are the suprahyoid muscles

Answer 1

Mylohyoid, geniohyoid, digastric, stylohyoid

Question 2

What are the infrahyoid muscles

Answer 2

Omohyoid, sternohyoid, thyrohyoid, sternothryoid

Question 3

Stylohyoid

Answer 3

Anterior triangle of neck
Origin: base of styloid process
Insertion: lateral area of body of hyoid bone
Innervation: facial nerve CNVII
Function: pulls hyoid bone upward in posterosuperior direction

Question 4

Digastric

Answer 4

Anterior triangle of neck
Anterior belly:
Origin: digastric fossa on Lower inside mandible
Insertion: attachment of tendon between 2 bellies to body of hyoid bone
Innervation: mylohyoid nerve from inferior alveolar branch of mandibular nerve V3
Function: opens mouth by lowering mandible raises hyoid bone
Posterior belly:
Origin: mastoid notch on medial side of mastoid process of temporal bone
Insertion: same as anterior belly
Innervation: facial nerve CNVII
Function: pulls hyoid bone upward and back

Question 5

Mylohyoid

Answer 5

Anterior triangle of neck
Origin: mylohyoid line on mandible
Insertion: body of hyoid bone and fibres from muscle on opposite side
Innervation: mylohyoid nerve from inferior alveolar branch of mandibular nerve V3
Function: support and elevation of floor of oral cavity; elevation of hyoid bone

Question 6

Geniohyoid

Answer 6

Anterior triangle of neck
Origin: inferior mental spine on inner surface of mandible
Insertion: anterior surface of body of hyoid bone
Innervation: branch from anterior ramus of C1 (carried along Hypoglossal nerve CNXII)
Function: fixed mandible elevates and pulls hyoid bone forward; fixed hyoid bone pulls mandible downward and inward

Question 7

Sternohyoid

Answer 7

Anterior triangle of neck
Origin: posterior aspect of sternoclavicular joint and adjacent manubrium of sternum
Insertion: body of hyoid bone medial to attachment of omohyoid muscle
Innervation: anterior rami of C1 to C3 through the ansa cervicalis
Function: depresses hyoid bone after swallowing

Question 8

Omohyoid

Answer 8

Anterior triangle of neck and posterior triangle
Origin: superior border of scapula medial to suprascapular notch
Insertion: lower border of body of hyoid bone just lateral to attachment of sternohyoid
Innervation: anterior rami of C1 to C3 through the ansa cervicalis
Function: depresses and fixes the hyoid bone

Question 9

Thryohyoid

Answer 9

Anterior triangle of neck
Origin: oblique line on lamina of thyroid cartilage
Insertion: greater horn and adjacent aspect of body of hyoid bone
Innervation: fibres from anterior ramus of C1 carried along Hypoglossal nerve CNXII
Function: depresses hyoid bone but when hyoid bone is fixed raises larynx

Question 10

Sternothyroid

Answer 10

Anterior triangle of neck
Origin: posterior surface of manubrium of sternum
Insertion: oblique line on lamina of thyroid cartilage
Innervation: anterior rami of C1 to C3 through the ansa cervicalis
Function: draws larynx (thyroid cartilage) downward

Question 11

Sternocleidomastoid

Answer 11

Posterior triangle of neck
Origin:
Sternal head- upper part of anterior surface of manubrium of sternum
Clavicular head- superior surface of medial one third of clavicle
Insertion:
Sternal head- lateral one half of superior nuchal line
Clavicular head- lateral surface of mastoid process
Innervation: accessory nerve CNXI and branches from anterior rami of C2 to C3 (C4)
Function: individually it tilts the head toward shoulder on same side rotating head to turn face to opposite side; together it draws head forward, flexion

Question 12

Trapezius

Answer 12

Posterior triangle of neck
Origin: superior nuchal line; external occipital protuberance; ligamentum nuchae; spinous processes of C7 to T12
Insertion: lateral 1/3 clavicle, acromion, spine of scapula
Innervation: motor- accessory nerve CNXI, proprioception- C3 and C4
Function: assists in rotation scapula during abduction of humerus above horizontal; upper fibres elevate, middle fibres adduct, lower fibres depress scapula

Question 13

Splenius capitis

Answer 13

Posterior triangle of neck
Origin: lower half of ligamentum nuchae, spinous processes of vertebrae C7 to T4
Insertion: mastoid process, skull below lateral 1/3 of superior nuchal line
Innervation: posterior rami of middle cervical nerves
Function: together draws head backward, individually draw and rotate head to one side

Question 14

Levator scapulae

Answer 14

Posterior triangle of neck
Origin: transverse processes of C1 to C4
Insertion: upper part of medial border of scapula
Innervation: C3, C4 and dorsal scapular nerve C4 C5
Function: elevates scapula

Question 15

Posterior scalene

Answer 15

Posterior triangle of neck
Origin: posterior tubercles of transverse processes of C4 to C6
Insertion: upper surface of rib 2
Innervation: anterior rami of C5 to C7
Function : elevation rib 2

Question 16

Middle scalene

Answer 16

Posterior triangle of neck
Origin: transverse processes of C2 to C7
Insertion: upper surface rib 1 posterior to groove for subclavian artery
Innervation: anterior rami of C3 to C7
Function: elevation rib 1

Question 17

Anterior scalene

Answer 17

Posterior triangle of neck
Origin: anterior tubercles of the transverse processes of C3 to C6
Insertion: scalene tubercle and upper surface rib 1
Innervation: anterior rami of C4 to C7
Function: elevates rib 1