Subclavius Muscle
Description
Name
- Subclavius
- Muscle under the clavicle
- Second pectoral muscle
- Musculus subclavius
General
- Small triangular muscle between the clavicle and first rib
- Contributes to the anterior wall of the axilla
Origin
- Rib 1 (costal cartilage and sternal half of rib)
Insertion
- Anteroinferior surface of Clavicle (middle 1/3)
Actions
- Depression and Stabilization of Clavicle
Vascular Supply
- Thoracoacromial Artery (Clavicular Branch)
- Suprascapular Artery
Innervation
- Subclavian Nerve (C5-C6)
Subclavius Posticus
- Rare accessory muscle variant that extends from the first rib or costal cartilage to the superior border of the scapula[3]
- Traverses the thoracic outlet and lies in close proximity to the brachial plexus and subclavian vessels
- May cause neurovascular compression and has been implicated in both neurogenic and vascular thoracic outlet syndrome
- Most cases are asymptomatic and discovered incidentally on imaging or during surgery
- Recognition of this variant is important when evaluating unexplained thoracic outlet symptoms
Clinical Significance
- Thoracic Outlet Syndrome
- Costoclavicular Syndrome
- Clavicle Fracture
- Subclavius Muscle Strain
- Sternoclavicular joint dysfunction
- Subclavius posticus syndrome
See Also
References
- ↑ Image courtesy of catalyst university
- ↑ Maślanka, Krystian, et al. "Congenital, acquired, and trauma-related risk factors for thoracic outlet syndrome—review of the literature." Journal of Clinical Medicine 12.21 (2023): 6811.
- ↑ Subclavius posticus muscle. Akita K, Ibukuro K, Yamaguchi K, Heima S, Sato T. The subclavius posticus muscle: a possible cause of thoracic outlet syndrome. Surg Radiol Anat. 2000;22(2):111-116.