Coccyx

Os coccygis

The coccyx is a small triangular bone at the inferior end of the vertebral column. It articulates superiorly with the sacrum at the sacrococcygeal joint. The coccygeal cornua project superiorly to articulate with the sacral cornua.

Tipo Bone
Sistema corporal Skeletal
Região corporal Pelvis
Estrutura pai bone of dorsum
Nome latino Os coccygis
FMA ID 20229

Função

The vestigial tailbone formed by fusion of 3-5 coccygeal vertebrae. Provides attachment for ligaments and muscles of the pelvic floor. Serves as a weight-bearing structure when sitting.

Significado clínico

Coccydynia (tailbone pain) results from falls or prolonged sitting on hard surfaces. Coccygeal fractures and dislocations can occur during childbirth. Rarely, pilonidal cysts develop in the sacrococcygeal region.

Perguntas frequentes

What is the coccyx and how does it form?
The coccyx, commonly called the tailbone, is the terminal segment of the vertebral column. It forms through the fusion of three to five small coccygeal vertebrae and is considered a vestigial structure—an evolutionary remnant of the tail present in our primate ancestors. Its Latin name, Os coccygis, derives from the Greek word for cuckoo, whose beak it was thought to resemble.
What functional roles does the coccyx serve?
Despite being vestigial, the coccyx is not entirely without function. It serves as an attachment point for several ligaments and muscles of the pelvic floor, including the gluteus maximus, the coccygeus muscle, and the anococcygeal ligament. It also acts as a weight-bearing structure when a person is seated, distributing force along with the ischial tuberosities.
What is coccydynia and what causes it?
Coccydynia is pain localized to the coccyx region. It most commonly results from a direct fall onto the tailbone, prolonged sitting on hard surfaces, repetitive strain, or childbirth trauma. The pain typically worsens when sitting or transitioning from sitting to standing, and may be accompanied by tenderness on palpation of the coccyx.
Can the coccyx be fractured during childbirth?
Yes. Coccygeal fractures and dislocations can occur during vaginal delivery, particularly when the baby's head exerts significant pressure during descent. The coccyx normally flexes backward to enlarge the pelvic outlet, but excessive force can cause fracture or subluxation, resulting in postpartum coccydynia.
What is a pilonidal cyst and how is it related to the coccyx?
A pilonidal cyst is a cyst or abscess that develops in the skin of the sacrococcygeal region, just above the cleft of the buttocks. It is thought to arise from ingrown hairs or hair follicles that become embedded under the skin. Though not arising from the coccyx itself, its location in this region links it anatomically to the coccyx and may require surgical drainage or excision.

Estruturas relacionadas

articulation joint nutrient foramen conduit outer fibrous layer of periosteum capsular layer of periosteum periosteum pre-cartilage condensation pre-chondrogenic condensation postcranial axial skeleton axial skeleton radial element actinost cavity of bone organ bone organ cavity

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Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.