Head & Neck Surgery Course

Dr Pierfrancesco PELLICCIA

Pr Benjamin LALLEMANT

Service ORL et CMF

CHU de Nîmes

CH de Arles

Surgical anatomy of the neck: muscles

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Summary (anterior & lateral view)

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Platysma

Origin

– fascia overlying the pectoralis

major and deltoid

Insertion

– depression muscles of the corner of the mouth

– the mandible

– the SMAS layer of the face

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Platysma

Surgical considerations

– Increases blood supply to

skin flaps

– Absent in the midline of

the neck

– Fibers run in an opposite

direction to the SCM

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Sternocleidomastoid Muscle (SCM)

Origin • Medial 1/3 of the clavicle

• manubrium

Insertion • mastoid process

Nerve supply • spinal accessory nerve (XI)

Blood supply • occipital a. or direct from ECA

• superior thyroid a.

• transverse cervical a.

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Function

– turns head toward opposite side and tilts head toward the ipsilateral shoulder

Surgical considerations

– Leave overlying fascia (superficial layer of deep cervical fascia down)

– Lateral retraction exposes the submuscular recess

Sternocleidomastoid Muscle (SCM)

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Trapezius Origin

– medial 1/3 of the sup. Nuchal line

– external occipital protuberance

– ligamentum nuchae

– spinous process of C7+T1-T12

Insertion

• lateral 1/3 of the clavicle

• acromion process

• spine of the scapula

Function

• elevate and rotate the scapula and stabilize the shoulder

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Trapezius

Surgical considerations

– Posterior limit of Level V neck

dissection

– Denervation results in shoulder

drop and winged scapula www.orl-nimes.fr

Infrahyoid muscles

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Omohyoid

Origin – upper border of the scapula

Insertion – hyoid bone lateral to the

sternohyoid muscle

Blood supply – Inferior thyroid a.

Function – depress the hyoid

– tense the deep cervical fascia

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Omohyoid

Surgical considerations

– Absent in 10% of individuals

– Surgical landmark demarcating level III from IV

– Inferior belly lies superficial to

• The brachial plexus

• Phrenic nerve

• Transverse cervical vessels

– Superior belly lies superficial to

• IJV

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Suprahyoid muscles

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Suprahyioid muscles and extrinsic tongue muscles in Level I

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Digastric

Origin – digastric fossa of the mandible (at

the symphyseal border)

Insertion – hyoid bone via the intermediate

tendon

– mastoid process

Function – elevate the hyoid bone

– depress the mandible (assists lateral pterygoid)

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Digastric

Surgical considerations

– Posterior belly is superficial to:

• ECA

• ICA

• IJV

• Hypoglossal & spinal nerves

– Anterior belly

• Landmark for identification of mylohyoid for dissection of level Ib

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Muscles of the floor of posterior triangle of the neck

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1: SCM

4: splenius cervicis

5: levator scapulae

1: splenius capitis

2: splenius cervicis (SCM resected)

Muscles of the floor of posterior triangle of the neck

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