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Scalene muscles أبريل 2019, https://www.ncbi.nlm.nih.gov/books/NBK519058/…
Scalene muscles
أبريل 2019
Def.
Scalene muscles are a group of 3 paired muscles located in the lateral aspect of the neck region.
They are named scalenus anterior, scalenus medius, and scalenus posterior.
They originate from the transverse processes of the cervical vertebrae and insert onto the first two ribs.
Topographic anatomy
Scalene muscles are located in the lateral aspect of the neck, deep to the platysma muscle and superficial to the brachial plexus and subclavian artery.
Scalene muscles are situated deep in the neck, anterior to the levator scapulae and posterior to the sternocleidomastoid muscle.
They are triangular in shape, with the apex directed superiorly and the base attached to the ribs.
Inferior thyroid artery supplies anterior scalene muscle.
ِِِِAscending or superficial cervical artery, directs the blood flow to medium scalene and posterior scalene.
The venous trunk responsible for draining blood from the scalene muscles is the brachiocephalic venous trunk. The latter derives from a branch known as the vertebral vein.
The drained lymph arrives in the jugular lymphatic trunks found both right and left.
Further, the right lymph will flow into the right lymphatic duct, while the lymph collected in the left portion will end in the thoracic duct.
Nerve supply
Anterior branches of the cervical spinal nerves from C3 to C8.
Scalene muscles involve the cervical plexus and the brachial plexus; the collaboration between the two complexes is fundamental for the different functions of these muscles.
Emberyological anatomy
They arise from the fourth to the eighth cervical somites which are transient segments of mesodermal tissue
Receive innervation from the cervical spinal nerves
The sclerotomes of the cervical somites give rise to the vertebral bodies, while the myotomes develop into the skeletal muscles of the neck, including the scalene muscles.
Applied anatomy
Scalene muscles can be involved in various clinical conditions such as thoracic outlet syndrome, in which compression of the brachial plexus and subclavian artery can occur between the scalene muscles.
This can lead to symptoms such as pain, numbness, tingling, and weakness in the upper limb.
Histological anatomy
Histologically, the scalene muscles consist of skeletal muscle tissue. They are composed of bundles of muscle fibers with associated connective tissue, blood vessels, and nerves.
Surgical anatomy
Scalene muscles are relevant in surgical procedures involving the neck and thoracic outlet.
In surgeries for thoracic outlet syndrome or cervical rib resection, the scalene muscles may need to be identified and carefully dissected to access and decompress the structures being compressed.
Physiological anatomy
The scalene muscles play a role in respiration and neck movement. They assist in elevating the ribs during forced inhalation and help in flexing and rotating the neck.
Anatomical complications
They include compression of nearby structures, nerve entrapment syndromes, lead to symptoms like pain, numbness, and weakness in the upper limb, or abnormal muscle insertions that can impact the function of the neck and upper limb and potentially contribute to musculoskeletal disorders.
https://www.ncbi.nlm.nih.gov/books/NBK519058/