[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) › First rib [Skeletal system](https://durgical.com/en/anatomy/system/skeletal-system/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # First rib The first rib is the shortest, most curved rib, at the base of the neck; the nerves and vessels to the arm cross over it. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=rib_1&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The short, curved top rib under the collarbone. ## What it does The brachial plexus and subclavian vessels cross it on their way to the arm. ## Key points - The broadest, shortest and most curved rib; the scalene tubercle (scalenus anterior) separates the [subclavian vein](https://durgical.com/en/anatomy/subclavian-veins/) in front from the subclavian artery and lower trunk of the brachial plexus behind - Floor of the interscalene triangle and of the costoclavicular space, two of the three sites of thoracic outlet compression (the third lies under the [pectoralis minor](https://durgical.com/en/anatomy/pectoralis-minor-muscle/)) - A first rib fracture signals high-energy trauma: injuries of the subclavian vessels and brachial plexus are looked for ## Key facts **Joints with** [T1 vertebra](https://durgical.com/en/anatomy/t1/) (head and tubercle), manubrium (via its cartilage) **Landmarks** Scalene tubercle; grooves for the subclavian vein (in front) and artery (behind) ## Relations **Above** [Scalenes](https://durgical.com/en/anatomy/scalenus-anterior-muscle/): scalenus anterior on the tubercle and scalenus medius behind the groove for the [subclavian artery](https://durgical.com/en/anatomy/right-subclavian-artery/) and the lower trunk of the [brachial plexus](https://durgical.com/en/anatomy/roots-of-brachial-plexus/) **In front** [Costoclavicular ligament](https://durgical.com/en/anatomy/costoclavicular-ligament/) and [subclavius](https://durgical.com/en/anatomy/subclavius/) tie it to the [clavicle](https://durgical.com/en/anatomy/clavicle/); its cartilage joins the [manubrium](https://durgical.com/en/anatomy/manubrium-of-sternum/) below the sternoclavicular joint **Behind** Head and tubercle against T1; crossing the front of its neck, from medial to lateral: [sympathetic trunk](https://durgical.com/en/anatomy/sympathetic-trunk/), superior intercostal artery and the ventral ramus of T1 rising to join the plexus **Medial** Inner border with the suprapleural membrane over the dome of the [pleura](https://durgical.com/en/anatomy/pleura/) and the lung apex ## How to find it Hard to feel: it lies behind the clavicle, and only its cartilage is felt just below the sternoclavicular joint at the side of the manubrium. On a [chest](https://durgical.com/en/anatomy/region/chest/) X-ray it is traced from its posterior end at T1. ## On imaging On a chest or cervical [spine](https://durgical.com/en/anatomy/region/spine/) X-ray, a cervical rib is told from a T1 rib by its vertebra: C7 transverse processes slope downward, T1 transverse processes slope upward. CT angiography with the arms raised shows vascular thoracic outlet compression. ## Clinical notes - Effort thrombosis of the subclavian vein (Paget–Schroetter syndrome) happens in the costoclavicular space between the first rib and the clavicle, in people who use the arms overhead - Resection of the first rib is one of the operations for thoracic outlet syndrome - Stress fractures occur in throwers and rowers; tumours of the lung apex (Pancoast tumour) can invade it with the lower brachial plexus ## Anatomical variants - Cervical rib, usually from C7 and in under 1% of people, on one or both sides; complete or fibrous bands can narrow the thoracic outlet ## Development [Ribs](https://durgical.com/en/anatomy/ribs/) start as the costal part of each vertebra's cartilage model, separate from it in the embryo and then ossify, except at the front, where cartilage stays as the [costal cartilage](https://durgical.com/en/anatomy/costal-cartilage/). A cervical rib is a costal element of C7 that keeps growing instead of staying small. ## Related conditions - [Thoracic outlet syndrome](https://durgical.com/en/conditions/thoracic-outlet-syndrome/) ## Test yourself Think of the answer, then tap the question to see it. ## On the first rib, what does the scalene tubercle separate? The subclavian vein in front from the subclavian artery and lower trunk of the brachial plexus behind; the scalenus anterior inserts on it. ## What does a first rib fracture signal? High-energy trauma: injuries of the subclavian vessels and brachial plexus are looked for. ## Where does effort thrombosis of the subclavian vein (Paget–Schroetter syndrome) occur? In the costoclavicular space between the first rib and the clavicle, in people who use the arms overhead. ## On X-ray, how is a cervical rib told apart from a first rib? By its vertebra: C7 transverse processes slope downward, T1 transverse processes slope upward. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/first-rib/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** costa prima TA2 1107 **Official Spanish (DeCS)** Primera costilla **English (TA2)** First rib **Also called** rib 1 ## Related - [Subclavian artery](https://durgical.com/en/anatomy/right-subclavian-artery/) - [Subclavian vein](https://durgical.com/en/anatomy/subclavian-veins/) - [Costoclavicular ligament](https://durgical.com/en/anatomy/costoclavicular-ligament/) - [Scalenes](https://durgical.com/en/anatomy/scalenus-anterior-muscle/) - [Subclavius](https://durgical.com/en/anatomy/subclavius/) Sources: Terminologia Anatomica (TA2); [Anatomy, Thorax, Wall](https://www.ncbi.nlm.nih.gov/books/NBK535414/); [Anatomy, Thorax, Cervical Rib](https://www.ncbi.nlm.nih.gov/books/NBK541001/); [7.5 Embryonic Development of the Axial Skeleton](https://openstax.org/books/anatomy-and-physiology-2e/pages/7-5-embryonic-development-of-the-axial-skeleton) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/first-rib/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/first-rib/