Anatomy

1. Muscular triangles of the neck
Dr. Mohammad Mahmoud Mosaed

2. Lateral side of the neck
• The lateral side of the neck is
bounded by;
• Anteriorly: the midline of the
neck
• Posteriorly: the anterior
border of the trapizuis muscle
• Superiorly: the mandible
• Inferiorly: the clavicle

3. • The lateral side of the
neck is divided by
sternocleidomastoid
muscle into 2 triangles:
• Anterior triangle
• Posterior triangle

4. The posterior trangle
• Boundaries:
• Posteriorly: by the trapezius muscle
• Anteriorly: by the sternocleidomastoid muscle
• Inferiorly: by the clavicle.
• Floor: prevertebral muscles "semispinalis capitis,
splenius capitis, levator scapulae and scalenus
medius”
• Roof: skin, superficial fascia and platysma
• The posterior triangle of the neck is further subdivided by
the inferior belly of the omohyoid muscle into a large
occipital triangle above and a small supraclavicular triangle
below.

7. Structures in Posterior Triangle
• The brachial plexus and
subclavian artery pass
between the scalenus
anterior and medius
muscles.
• The subclavian vein
passes anterior to the
scalenus anterior
muscle.

9. Anterior triangle of the neck:
Boundaries:
• Superior: the lower border of the mandible.
• Lateral: the posterior border of the sternomastoid muscle.
• Medially: the midline.
• Roof: The skin, platysma muscle, superficial veins and
nerves, deep fascia.
Subdivisions of anterior triangle
• Digastric triangle
• Submental triangle
• Carotid triangle
• Muscular triangle

11. The muscular triangle:
• Boundaries:
• Laterally the posterior border of the sternomastoid,
• Superiorly the superior belly of the omohyoid muscle
• Anteriorly the midline.
• Contents:
• Superior belly of omohyoid
• Sternohyoid
• Sternothyroid
• Thyrohyoid
• Thyroid gland
• Parathyroid gland
• Cervical part of trachea and esophagus

13. The digastric triangle
• Boundaries: the lower border of the mandible above
and the two bellies of the digastric muscles on each side.
• Floor: the myelohyoid muscle in front and the hyoglossus
behind.
• Contents:
• The submandibular salivary gland with its duct,
• The submandibular lymph nodes,
• The facial artery.
• The lingual nerve and submandibular ganglion
• The hypoglossal nerve

14. Boundaries
mastoid & mandible above
anterior belly of digastric
posterior belly of digastric

15. The submental triangle:
• Boundaries:
• Anteriorly: the midline.
• Laterally: the anterior
belly of digastric
• Inferiorly: the hyoid bone
• Floor: The myelohyoid
muscle
• Contents:
• Submental vessels, nerve
and lymph nodes.

17. The carotid triangle
Boundaries:
• Laterally the posterior border of sternomastoid
• Above and medially the posterior belly of digastric muscle
inferiorly and medially the superior belly of omohyoid
muscle
• Floor: the middle constrictor of the pharynx.
Contents:
• Vessels; the external carotid artery with its superior thyroid,
ascending pharyngeal, lingual and facial branches, the carotid
sheath containing the internal carotid artery, internal jugular
vein and vagus nerve,
• Nerves; the ansa cervicalis overlying the carotid sheath, the
sympathetic trunk deep to the sheath and the hypoglossal nerve
crosses both the internal and external carotids. The accessory
nerve runs on the lateral side of the vessels for a short distanc
• Lymph Nodes; deep cervical lymph nodes

18. The boundaries of the carotid triangle
• posterior belly of digastric
muscle (pbd)
• superior belly of the
omohyoid muscle (so)
• anterior border of
sternomastoid muscle (st)