13. Occipital triangle
Floor
1. Semispinalis capitis (vertically disposed)
2. Splenius capitis
3. Levator scapulae
4. Scalenus medius and posterior
All these muscles are covered with prevertebral fascia which forms the
floor of the triangle
14.
15. Contents of the triangle
1. Nerves
2. Blood vessels
3. Lymph nodes
16. Nerves in the triangle lie in 3 groups:
• Superficial
• Intermediate
• deep
17. Superficial nerves in the occipital triangle (are cutaneous branches of
cervical plexus). All emerge from the middle of the posterior border of
the sternocleidomastoid
• Great auricular nerve(C2,C3)
• Lesser occipital nerve (C2)
• Transverse cervical cutaneous nerve (C2,C3)
• Supraclavicular nerves (C3, C4) which divide into medial, intermediate
and lateral nerves, pass downwards, and cross the clavicle to supply
the anterior chest wall upto the 2nd costal cartilage
18.
19.
20.
21. Intermediately placed nerve in the occipital triangle:
Spinal accessory nerve-(C1-C6)
• This emerges from the skull along with the cranial accessory nerve through
the jugular foramen
• It separates from its cranial counterpart
• It pierces the sternocleidomastoid and supplies it
• It emerges from the middle of the posterior border of the muscle
• It passes downwards and backwards (plastered to the fascial roof of the
triangle) lying on levator scapulae
• It pierces the trapezius 5cms above the clavicle and supplies it
22.
23.
24. Nerves placed deep to the fascial floor of the occipital triangle:
1. C3, C4- accompany the spinal accessory nerve and supply
proprioceptive fibers to the trapezius
2. Upper trunk of brachial plexus (which emerges between the scaleni
anterior and medius and has a root value of C5, C6)
3. Dorsal scapular nerve- C5-is a branch of the brachial plexus
25.
26.
27.
28. Blood vessels in the occipital triangle
• Superficial cervical artery (branch of the thyro cervical branch of the
subclavian artery-crosses the floor of the triangle and disappears
deep to the trapezius
• Occipital artery –branch of external carotid artery-crosses the apex of
the triangle
29.
30. Branches of subclavian artery
VIT C D
V=vertebral artery
I=internal thoracic artery
T=thyrocervical trunk (which branches into SIS= superficial cervical
artery, inferior thyroid artery, supra scapular artery)
C = Costo cervical trunk (gives branches superior intercostal artery and
deep cervical artery)
D=Dorsal scapular artery
31.
32.
33.
34.
35. Applied Anatomy
• Since the external jugular vein pierces the investing layer of deep
cervical fascia and is adherent to it, a cut vein would be unable to
retract and air could be sucked into the vein causing an air embolism
• Cancer of the stomach and abdominal organs might spread to the left
sided supra clavicular lymph node (Virchow’s node) along the thoracic
duct.
• The upper trunk of the brachial plexus could be injured in the
occipital triangle leading to Erb’s paralysis
42. Floor
• Outer border of the first rib
• Scalenus medius and scalenus anterior
• First digitation of serratus anterior
43.
44.
45.
46. Contents
• 3rd part of subclavian artery-which extends beyond the scalenus
anterior muscle upto the outer border of the first rib. It continues as
the axillary artery
• Suprascapular artery and superficial cervical arteries (branches of the
thyro cervical branch of the subclavian artery)
• Dorsal scapular artery (branch of the third part of the subclavian
artery)
47.
48. Contents
• Subclavian vein-which is a continuation of the axillary vein. It unites
with the internal jugular vein to form the brachiocephalic vein
• Terminal part of the external jugular vein-it pierces the investing layer
of deep cervical fascia and drains into the subclavian vein
49.
50. Contents
• Branches of the brachial plexus (nerve to serratus anterior, dorsal
scapular nerve, supra scapular nerve, nerve to subclavius muscle)
51. Applied anatomy
• Subclavian steal syndrome-
• In case of an obstruction of the subclavian artery proximal to the
origin of the vertebral artery, there is hypotension in the ipsilateral
vertebral artery which will cause a retrograde flow of blood in the
vertebral artery resulting in ischemic injury to the brain tissue
