Which is the lowest bone in the human body?

September 22, 2025 •

2 min read

An adult human has 206 bones, each with a specific location and function. Among these many components, the question of which is the lowest bone in the human body might seem simple, but the answer highlights some fascinating aspects of human anatomy.

Quick Summary

The lowest bone in the human body is the coccyx, also known as the tailbone, which forms the terminal end of the vertebral column.

Key Points

The Coccyx (Tailbone) is the lowest bone: It is the terminal segment of the vertebral column, positioned below the sacrum.
The Coccyx is a fused bone: It is typically formed by the fusion of three to five small vertebrae, a process that usually completes by age 30.
The Coccyx aids in weight distribution: It works with the pelvis to support body weight when a person is sitting down.
The Coccyx serves as an anchor point: Important pelvic floor muscles and ligaments attach to the coccyx, providing stability and support for the pelvis and its contents.
Injury to the coccyx can cause significant pain: A condition known as coccydynia, or tailbone pain, can be caused by falls, repetitive strain, or childbirth.

Understanding the Coccyx: The Tailbone

The coccyx, or tailbone, is the lowest bone in the human body. Located at the bottom of the spine, below the sacrum, this small, triangular bone is typically made of three to five small vertebrae that fuse by around age 30. It provides stability and supports weight while sitting.

The Anatomy of the Coccyx

The coccyx is a vestigial bone that was part of a tail in ancestors. Its shape varies, and it attaches to the sacrum. It serves as an anchor for muscles and ligaments like the gluteus maximus and pelvic floor muscles.

Function and Purpose

Although small, the coccyx is vital for body mechanics.

Weight Distribution: It helps distribute body weight when sitting, working with the pelvis for balance and stability.
Muscle and Ligament Anchor: It's an attachment point for pelvic floor muscles and ligaments, crucial for bowel control and organ support.
Shock Absorber: The coccyx absorbs shock and pressure when sitting.

The Lower Extremities: A Comparative Look

While the coccyx is the lowest part of the axial skeleton, the appendicular skeleton includes limb bones. Bones in the foot are often considered, but the coccyx is the lowest relative to the body's midline.

Tarsal Bones

These seven bones form the ankle and upper foot, including the calcaneus (heel bone). The calcaneus is the largest foot bone and forms the heel. However, the coccyx is the most inferior bone relative to the central skeletal structure, especially when seated.

Phalanges

Toe bones (phalanges) are the most distal appendicular bones but are lateral and anterior to the coccyx, not directly below it.

Comparison of Coccyx vs. Foot Bones


Feature	Coccyx (Tailbone)	Calcaneus ( Heel Bone)
Skeletal Group	Axial Skeleton	Appendicular Skeleton
Location	Terminal end of the vertebral column	Largest of the tarsal bones in the foot
Primary Function	Weight-bearing support while seated, pelvic floor muscle attachment	Forms the heel, weight-bearing while standing, propulsion during gait
"Lowest" Claim	Most inferior bone relative to the body's central axis	Furthest distal bone, but not lowest on the axial plane

Potential Issues and Injuries

Coccydynia, or tailbone pain, can result from falls, prolonged sitting, or childbirth. This pain can significantly affect daily activities. Treatment often involves conservative measures, but persistent pain requires medical attention.

Conclusion: The Lowest Bone in Context

The coccyx is the lowest bone in the human body along the central axis. This small, fused bone at the base of the spine is crucial for weight-bearing, muscle attachment, and pelvic support. Its position and evolutionary history make it unique. While foot bones are at the body's farthest points, the coccyx holds the title of the lowest bone in the core skeletal structure.

For more information on the intricate anatomy of the human skeletal system, consider visiting the official website of the National Institutes of Health: https://www.ncbi.nlm.nih.gov/.

Frequently Asked Questions

The coccyx is the lowest bone because it is the most inferior bone of the axial skeleton, the body's central core. While bones in the feet, such as the calcaneus, are physically lower when standing, the coccyx occupies the lowest position along the body's vertical axis.

Despite its small size, the coccyx is an important anchor for muscles and ligaments of the pelvic floor, and it helps support your weight and balance while you're sitting.

Yes, the coccyx is susceptible to injury, most commonly from falls where a person lands directly on their tailbone. This can cause a bruise or fracture, leading to coccydynia, or tailbone pain.

In medical terms, the coccyx is often referred to as a single bone, but it is actually a structure formed from the fusion of three to five small vertebrae that begins in the 20s and is often complete by the age of 30.

The sacrum is a larger, triangular bone located at the base of the lumbar vertebrae, right above the coccyx. The coccyx is the final, smaller bone at the very end of the spinal column.

Yes, while considered a vestigial remnant, the coccyx is important for anchoring the muscles and ligaments that form the pelvic floor, which are critical for controlling bowel function and providing pelvic stability.

Treatment for tailbone pain often involves conservative approaches, such as pain medication, physical therapy, using a specialized coccyx cushion while sitting, and avoiding activities that worsen the pain.