Scalenus Anterior Muscles
The scalenus anterior is an impt muscle of the lower part of the neck
because of its relations with the impt structures in that region
Origin
from the ant tubercles of the tnvs processes of CV3, 4, 5 & 6
Insertion
The fibres are inserted into
1. scalene tubercle on inner border of 1st rib
2. ridge on upper surface of 1st rib
Innervation
from ventral rami of C4, 5 & 6
Action
1. assists elevating 1st rib
2. when acting from below, it laterally flexes & rotates cervical part of vertebral column
Relations
Anteriorly | Posteriorly | Medially | Laterally |
1. prevertebral layer of deep cervical fascia 2. phrenic n 3. supf cervical & suprascapular art 4. IJV & subclavian vein | 1. subclavian art 2. brachial plexus 3. cervical dome of pleura | 1. vertebral art & v 2. inf thyroid art 3. thyrocervical trunk 4. symp trunk 5. on the left side, thoracic duct | 1. roots of brachial plexus 2. subclavian art 3. roots of phrenic n |