Pulsatile masses are mostly suggestive of vascular lesions or closely related to blood vessels. Imaging examinations such as angiography and blood flow ultrasound can clearly localize, quantify and qualify the diagnosis, and provide detailed information about the blood supply and its relationship with the surrounding great vessels. A pulsating mass on the clavicle is the clinical manifestation of peripheral aneurysm. Peripheral aneurysms are aneurysms that occur in each main artery, such as the carotid artery and the extremity arteries. The former is usually caused by atherosclerosis, and its aneurysm wall contains the three-layer structure of the arterial wall, and may be multiple or coexist with aortic aneurysm; the latter is often secondary to arterial trauma (e.g. stabbing injury, arterial puncture), and its aneurysm wall is fibrous tissue, and is mostly solitary. Various infectious factors (such as infectious emboli shed during bacterial endocarditis) can also destroy the arterial wall and form so-called infected aneurysms. The following diseases may also cause pulsatile masses: 1. subclavian-axillary aneurysm Aneurysm of the distal part of the subclavian artery often involves the first segment of the axillary artery and is called subclavian-axillary aneurysm. The most common cause is thoracic outlet syndrome due to cervical rib and fibrous cords, mostly seen in young women, with the right side being the most common. 2, goiter with normal thyroid function The thyroid gland has a strong ability to concentrate iodine, and the human thyroid gland needs 60 – 80ug of iodine per day to produce physiologically active thyroid hormones. In the body, there is a feedback relationship between thyroid hormone secreted by the thyroid gland and thyrotropic hormone (TSH) secreted by the pituitary gland, which is interdependent and mutually restrictive. , causing hypertrophy and hyperplasia of the thyroid gland. 3, abdominal abscess Abdominal abscess refers to a gap or part of the abdominal cavity due to tissue necrosis liquefaction, wrapped by intestinal curvature, viscera, abdominal wall, omentum or mesentery, etc., forming a limited accumulation of pus. This includes subphrenic abscesses, pelvic abscesses and inter-intestinal abscesses. Various diseases causing secondary peritonitis, abdominal surgery and after trauma can cause this disease. 4, hair cysts Hair cysts (trichilemmal cysts) are also known as hair sheath cysts (trichilemmal cysts). Trichilemmal cysts are autosomal dominant and originate in the isthmus of anagen hairs or in the follicles surrounding degenerating and resting hairs. Hair cysts are easily excised and appear as firm, smooth white cysts. It can be diagnosed according to clinical manifestations and histopathology. 5.Acute abscess Acute abscess (Acute abscess) is caused by bacterial infection, including Staphylococcus aureus, Streptococcus spp. etc., which causes local redness, swelling, pain and pressure pain, followed by fluctuating sensation with pus formation.