Scalenus Minimus

Original Editor - Wendy Walker

Top Contributors - Ines Musabyemariya, Vanessa Rhule, Kim Jackson, Wendy Walker and Evan Thomas

Description

Scalenus Minimus is part of the Scalene group of lateral neck muscles, this muscle may be present or Absent. It is absent in a large percentage of the population. Cadaver studies report finding it on one side in between 7%^[1] and 46%^[2] of the population. This muscle is also named Albinus Muscle, Sibson Muscle^[3].

Origin

The Scalenus Minimus is a small muscle located in the neck, primarily arising from the transverse processes of the cervical vertebrae. Most commonly, it originates from either the sixth (C6) or seventh (C7) cervical vertebra^[4].

Insertion

The insertion of the scalenus minimus is typically at the first rib and supra-pleural fascia. It attaches to the outer surface of the first rib near the area where the anterior scalene muscle inserts^[4].

Nerve Supply

The nerve supply of the scalenus minimus muscle is typically provided by the lower cervical nerves, specifically the anterior rami of C5 and C6/C7&8^[4].

Blood Supply

The blood supply to the scalenus minimus muscle primarily comes from the branches of the subclavian artery. Specifically, it receives blood from the transverse cervical artery and the suprascapular artery, both of which are branches of the subclavian artery. Additionally, the scalene muscles may also receive some supply from the deep cervical artery, which branches from the costo-cervical trunk of the subclavian artery^[4].

Action

Acting from above, in conjuction with Anterior Scalene and Middle Scalene: elevation of 1st rib

Helps raise and tense the dome of the parietal pleura

Function

The scalenus minimus muscle, although not present in all individuals, serves a few important functions when it is present^[4]. Primarily, it assists in the following:

Respiration: The muscle can help elevate the first rib during inhalation, contributing to the expansion of the thoracic cavity.
Neck Flexion: It may play a role in flexing the neck laterally when acting together with other scalene muscles.
Stability : The scalenus minimus helps stabilize the cervical spine during head and neck movements.

References

↑ Natsis K, Totlis T, Didagelos M, Tsakotos G, Vlassis K, Skandalakis P. Scalenus Minimus Muscle: Overestimated or Not? An Anatomical Study. The American SurgeonTM. 2013;79(4):372-374.
↑ Patel NT, Smith HF. Clinically Relevant Anatomical Variations in the Brachial Plexus. Diagnostics (Basel). 2023 Feb 22;13(5):830.
↑ Fawcett E. What is Sibson's Muscle (Scalenus pleuralis)? J Anat Physiol. 1896 Apr;30(Pt 3):433-6.
↑ ^4.0 ^4.1 ^4.2 ^4.3 ^4.4 Bordoni B, Varacallo M. Anatomy, Head and Neck, Scalenus Muscle.Treasure Island (FL): StatPearls Publishing; 2024 Jan.

[1] Natsis K, Totlis T, Didagelos M, Tsakotos G, Vlassis K, Skandalakis P. Scalenus Minimus Muscle: Overestimated or Not? An Anatomical Study. The American SurgeonTM. 2013;79(4):372-374.

[2] Patel NT, Smith HF. Clinically Relevant Anatomical Variations in the Brachial Plexus. Diagnostics (Basel). 2023 Feb 22;13(5):830.

[3] Fawcett E. What is Sibson's Muscle (Scalenus pleuralis)? J Anat Physiol. 1896 Apr;30(Pt 3):433-6.

[:0-4] 4.0 ^4.1 ^4.2 ^4.3 ^4.4 Bordoni B, Varacallo M. Anatomy, Head and Neck, Scalenus Muscle.Treasure Island (FL): StatPearls Publishing; 2024 Jan.

[1]

[2]

[3]

[4]