Scalenus ms

1
Scalenus Anterior Origin From the transverse
processes of the 3rd 4th 5th and 6th cervical
vertebrae. Insertion Into the scalene tubercle
on the inner border of the 1st rib and into the
ridge on the upper surface of
the 1st rib. Nerve Supply From the anterior
rami of the 4th 5th and 6th cervical
nerves. Action It assists in elevation the 1st
rib. When acting from below, it laterally flexes
the cervical part of the
vertebral column.
2
Relation of scalenus anterior muscle Anteriorly
The prevertebral layer of deep cervical fascia,
which binds the phrenic nerve down to the
anterior surface of the muscle the superficial
cervical and suprascapular arteries which cross
the phrenic nerve and the internal jugular and
subclavian veins. Posteriorly The subcalvian
artery brachial plexus and the cervical dome of
the pleura. Medially The vertebral arteryvein
inferior thyroid artery thyrocervical trunk
sympathetic trunk and on the left side, thoracic
duct. Laterally The roots of the phrenic nerve
unite at the lateral border of the muscle at the
level of the cricoid cartilage. Then it descends
on its anterior surface. The roots of the
brachial plexus subclavian artery emerge from
behind the lateral border of it to enter the
posterior triangle of neck.
3
Scalenus Medius Origin From the transverse
processes of the upper six cervical
vertebrae. Insertion Into the upper surface of
the 1st rib behind the groove for the subclavian
artery. It lies behind the roots of the brachial
plexus and behind the subclavian artery. Nerve
Supply Branches from the anterior rami of the
cervical nerves. Action like scalenus anterior.
4
Scalenus Posterior Origin From the transverse
processes of the lower cervical
vertebrae. Insertion Into the outer surface of
the second rib. Nerve supply branches from the
anterior rami of the lower cervical
nerves. Action Elevates the 2nd rib. When
active from below, it laterally flexes the
cervical part of the vertebral
column.
5
3
4
2
1
Anterior vertebral ( prevertebral ) muscles 1-
Longus coli. 2- Longus capitis. 3- Rectus capitus
anterior. 4- Rectus capitus lateralis.
6
Longus Colli Muscle

• Origin
• Anterior tubercle of C1, bodies of C1 to C3 and
  transverse processes of C3 to C6 vertebrae
• Insertion
• Bodies of C5 to T3 vertebrae, transverse
  processes of C3 to C5 vertebrae
• Action
• Flexes neck with rotation to opposite side

7
Longus Capitis Muscle

• Origin
• Basilar part of occipital bone
• Insertion
• Anterior tubercles of C3 to C6 transverse
  processes
• Action
• Flexes the head

8
Rectus Capitis Anterior

• Origin
• Base of the skull, just anterior to the occipital
  condyle
• Insertion
• Anterior surface of lateral mass of atlas
• Action
• Flexes the head

9
Rectus Capitis Lateralis

• Origin
• Jugular process of occipital bone
• Insertion
• Transverse process of atlas
• Action
• Flexes head and helps stabilize it

10
Scaleno-vertebral triangleIts boundaries are
the Longus colli scalenus anterior and the
transverse process of 6th cervical vertebra.It
contains 1st part of subclavian artery
sympathetic chain vertebral artery and the
thoracic duct ( on left side ).
11
Cervical plexus It is formed by anterior rami
of 1, 2, 3 4 cervical nerves.
The rami are joined by connecting branches
forming a loops on the levator scapulae and
scalenus medius muscles.
It is covered by the prevertebral fascia.
It is related to the internal jugular vein
within the carotid sheath.
12

• Branches
• 1- Cutaneous
• lesser occipital greater
  auricular transverse cutaneous and
  supraclavicular nerves.
• 2- Phrenic nerve to the diaphragm
• 2- Muscular
• - Prevertebral muscles -
  Sternocleidomastoid (C2 C3 as
  proprioceptive ).
• - Levator scapule (C3C4motor
• - Trapezius ( C3 C4 as
  proprioceptive ).
• - A branch of C1 joins the
  hypoglossal nerve then it leaves
  it to supply the thyrohoid
  geniohyoid.
• - Some of C1 fibers
  (descending branch) unites with the
  descending cervical nerves of C2 C3 to form
  the ansa cervicalis which supplies
  omohyoid sternohyoid and
  sternothyroid muscles.

C2
13
Phrenic Nerve It arises from the 3rd 4th and
5th cervical nerves of cervical plexus.
It runs vertically downward
acrosses the front of the scalenus anterior from
its lateral to medial border behind the
prevertebral layer of deep cervical fascia.
It enters the thorax by passing in front of
the subclavian artery and behind the beginning of
the brachiocephalic vein.
14
Relations Anteriorly The prevertebral layer of
the deep fascia internal jugular vein
superficial cervical and suprascapular arteries
beginning of the brachiocephalic vein and on the
left side the thoracic duct. Posteriorly The
scalenus anterior subclavian artery and the
cervical dome of pleura.
15
Branches 1- It is the only motor nerve supply to
the diaphragm. 2- It contains sympathetic
fibers. 3- It contains proprioceptive sensory
fibers ( stimulation of the sensory nerve
ending in the muscles tendons and joints )
for the muscles of the diaphragm. 4- It contains
sensory fibers for the mediastinal pleura and the
pericardium. 5- It contains Sensory fibers for
the pleura peritoneum covering the upper and
lower surfaces of the central part of the
diaphragm.