Cervical Triangles Flashcards
Platysma OIAN
Origin: deep fascia covering the pectoralis major and deltoid muscles
Insertion: lower margin of the body of mandible blending with the muscle at the angle of the mouth
Nerve supply: cervical branch of facial nerve
Action: depresses the mandible and draws the lower lip and angle of the mouth
Posterior Triangle Boundries
- Anteriorly: the SCM
- Posteriorly: the trapezius muscle
- Inferiorly: the middle third of clavicle
Posterior Triangle Contents
Arteries: subclavian, superficial
(transverse) cervical, suprascapular,
occipital artery–>Branch of the external Carotid aa.
Veins: external jugular and its tributaries, subclavian vein
• Nerves: brachial plexus, spinal accessory (SCM & Upper Trap.), branches of cervical plexus
Posterior Triangle Divisions
- the inferior belly of the omohyoid muscle divides the posterior triangle into two smaller
triangles ( Occipital Triangle and Supraclavicular Triangle)
Supraclavicular triangle
is the smaller triangle between inferior part
of SCM, inferior belly of omohyoid
and middle third of clavicle.
(subclavian triangle b/c subclavian aa. vv. go through it)
Occipital triangle
between SCM, trapezius and inferior belly of
omohyoid.
Omohyoid OIAN
Origin: scapular notch
Insertion: Later Hyoid Bone
Action: Depress Hyoid bone
Nerve:
Posterior Triangle Floor
Floor • prevertebral fascia • splenius capitis • levator scapulae • middle scalene • posterior scalene • anterior scalene, occasionally
Anterior Scalene OIAN
- Origin: Anterior tubercles of TPs of C3-C6
- Insertion: First rib
- Nerve supply: Ventral rami of C4-C6
• Action: Bilaterally, it elevates first
rib. Unilaterally, it laterally flexes
and rotates the neck.
Anterior Scalene Relations
- Anteriorly:
- Subclavian vein
- Transverse cervical and suprascapular arteries
- Phrenic nerve
- Posteriorly:
- Subclavian artery
- Brachial plexus
- Medially:
- Vertebral artery & vein
- Thyrocervical trunk
- Laterally:
- Roots of brachial plexus
Middle Scalene OIAN
- Origin: Posterior tubercles of TPs of C2-C7
- Insertion: Upper surface of first rib behind groove for subclavianartery
- Nerve supply: Ventral rami of C3 to C8
- Action: Bilaterally, it elevates first rib. Unilaterally, it laterally flexes the neck
Posterior Scalene OIAN
- Origin: Posterior tubercles of TPs of C4-C6 or C5-C7
- Insertion: Outer surface of second rib
- Nerve supply: Ventral rami of C6 to C8
- Action: Bilaterally, it elevates second rib. Unilaterally, it laterally flexes the neck
Anterior Triangle Boundries
Anterior: midline of the neck
Posterior: anterior border of SCM
Superior: lower margin of mandible
Submental Triangle Boundries
- Medial: midline of the neck
- Lateral: anterior belly of digastric muscle
- Inferior: body of hyoid bone
Submental Triangle Contents
Contents
• Lymph nodes
• Beginning of anterior jugular v.
Digastric Triangle Boundries
- Medial: anterior belly of digastric
- Lateral: posterior belly of digastric
- Superior:lower border of mandible
Digastric Triangle Contents
Contents • Submandibular gland • Facial a. & v. • Lymph nodes • Hypoglossal n. • Mylohyoid nerve • Carotid a., IJV, vagus • Stylohyoid • Glossopharyngeal n. • Lower part of parotid gland
Carotid Triangle Boundries
- Medial: superior belly of omohyoid
- Lateral: anterior border of SCM
- Superior: posterior belly of digastric
Carotid Triangle Contents
Contents • CCA, ECA, & ICA • Branches of ECA • IJV & tributaries • Internal & external laryngeal nerves • IX, X, & XII cranial nerves • Deep cervical lymph nodes
Muscular Triangle Boundries
- Medial: midline of the neck
- Inferior: anterior border of SCM
- Superior: superior belly of omohyoid
Muscular Triangle Contents
Contents: • Sternohyoid • Sternothyroid • Thyroid gland • Larynx • Trachea • Esophagus • Recurrent laryngeal nerve
Digastric Muscle OIAN
The muscle has anterior and posterior bellies connected by an intermediate tendon.
Origin: By posterior belly from medial surface of mastoid process
Insertion: By anterior belly into the digastric fossa of the mandible
Nerve supply:
• Posterior belly by facial nerve
• Anterior belly by nerve to mylohyoid
Action: Depresses the mandible or elevates the hyoid bone.
Stylohyoid Muscle OIAN
Origin: styloid process of temporal bone
Insertion: The muscle passes downward and forward along the upper border of the posterior belly of digastric muscle and inserts into the
hyoid bone at the junction of the body and greater cornu. It is pierced near its insertion by the intermediate tendon of digastric muscle.
Nerve supply: Facial nerve
Action: Elevates the hyoid bone.
Mylohyoid Muscle OIAN
Origin: Mylohyoid line of the mandible
Insertion: The posterior fibers inert into the body of the hyoid bone. The anterior fibers insert into a fibrous raphe, which extends from the symphysis menti to the body of the hyoid bone.
Nerve supply: Mylohyoid nerve, a branch of inferior alveolar, a branch of the mandibular nerve.
Action: Elevates the hyoid bone when the mandible is fixed and depresses the mandible when the hyoid bone is fixed.
