Posterior triangles of the neck Flashcards
Sternocleidomastoid muscle divides neck into
ant and post triangles
Posterior triangle
Mm sternocleidomast, trapezius
- Occipital Δ
- Supraclavicular Δ
Cross-section through the deep cervical fascia
deep cervical fascia consists of 3 layers
Superficial layer of the deep fascia (investing layer)
Prevertebral layer of the fascia
Pretracheal fascia
Deep cervical fascia also contains the carotid sheath
Vertical organization
Carotid sheath contains:
Common and internal carotid artery
Internal jugular vein
Vagus nerve
Deep cervical lymph nodes
Retropharyngeal space
Potential space
Between visceral part of pre- vertebral fascia and buccopharyngeal fascia
Sternocleidomastoid muscle nerve supply
Spinal accessory nerve (CNXI) + C3 and C4
Sternocleidomastoid muscle
Unilateral contraction
Laterally flexes neck
Rotates
Sternocleidomastoid muscl
Bilateral contraction
Extends neck AO joint
Flexes neck
Divides neck into anterior and lateral cervical regions
Sternocleidomastoid muscle
Lateral cervical regions
– where we find ant and post triangles of the neck
Sternocleidomastoid muscle has two heads:
Sternal head
Clavicular head
Sternal head
– Rounded tendon attaches to the manubrium
Clavicular head
- Thick fleshy – attaches to the surface of the medial third of the clavicle
The two heads of the sternocleidomastoid muscle are separated inferiorly by a space, visibly superficial as a small triangular depression
= lesser supraclavicular fossa
The heads of the sternocleidomastoid muscle join superiorly as they
pass obliquely upwards towards the cranium
Sternocleidomastoid muscle
Superior attachment:
Mastoid process of temporal bone and superior nuchal line of occipital bone
Investing layer of deep cervical fascia splits to form a sheath
= sternocleidomastoid muscle
