sacrum
C2Technical / Medical / Academic
Definition
Meaning
The large, triangular bone at the base of the spine, formed from fused vertebrae and situated between the two hip bones of the pelvis.
In a broader anatomical or zoological context, the sacrum is a key structural element in the vertebrate pelvic girdle, crucial for weight-bearing and stability. In some religious or historical contexts, it can be associated with the sacred (from its Latin root), but this usage is rare and archaic.
Linguistics
Semantic Notes
The term is almost exclusively used in anatomical, medical, osteopathic, chiropractic, and biological contexts. It is a countable noun (plural: sacra or sacrums). Its meaning is highly specific and does not have common figurative uses.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Pronunciation differs slightly (see IPA). Spelling is identical.
Connotations
Identical technical connotations in both varieties.
Frequency
Equally low-frequency in both dialects, confined to specialist fields.
Vocabulary
Collocations
Grammar
Valency Patterns
The sacrum [verb of state: articulates with, supports, is fused]A [adjective: fractured, fused, misaligned] sacrumVocabulary
Synonyms
Neutral
Weak
Usage
Context Usage
Business
Not used.
Academic
Used in medical, biological, anatomical, and physical therapy papers and textbooks.
Everyday
Virtually never used in everyday conversation unless discussing a specific injury or anatomy.
Technical
The primary register. Used in medical diagnoses, surgical reports, chiropractic assessments, osteopathy, and comparative anatomy.
Examples
By Part of Speech
adjective
British English
- The sacral nerves exit through openings in the bone.
- She had a sacral stress fracture.
American English
- The sacral nerves exit through openings in the bone.
- She was diagnosed with a sacral stress fracture.
Examples
By CEFR Level
- The doctor said the pain might be coming from his sacrum.
- The sacrum is a bone in your lower back.
- A fall onto the buttocks can result in a fractured sacrum.
- The sacrum connects the spine to the hip bones.
- The patient's MRI revealed a slight misalignment of the sacrum within the pelvic girdle.
- In humans, the five sacral vertebrae fuse into a single sacrum by early adulthood.
Learning
Memory Aids
Mnemonic
Think: 'The SACRUM is at the SACRED core of your structure,' linking to its Latin root 'sacer' (sacred) and its central, foundational role in the pelvis.
Conceptual Metaphor
FOUNDATION / KEYSTONE: The sacrum is metaphorically the 'keystone' of the pelvic arch, locking the hip bones together and bearing the weight of the upper body.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'крестец' (krestets), which is the correct translation. Avoid false cognates like 'сакральный' (sacral, meaning sacred/ritual), which shares an etymological root but has a completely different modern meaning in Russian.
Common Mistakes
- Mispronouncing it as /səˈkruːm/ or /ˈsæk.rʊm/.
- Using it as a general term for 'lower back'.
- Confusing it with the coccyx (tailbone).
- Incorrect plural: 'sacra' is technically correct, but 'sacrums' is also accepted in non-technical contexts.
Practice
Quiz
What is the primary function of the sacrum?
FAQ
Frequently Asked Questions
Yes, etymologically. It comes from Latin 'os sacrum', meaning 'holy bone'. This was perhaps due to its role in sacrificial animals or its perceived importance.
The sacrum is the large, triangular bone above the coccyx (tailbone). The coccyx is a smaller, remnant structure of 3-5 fused vertebrae at the very bottom of the vertebral column.
Yes, a sacral fracture is a serious injury, often caused by high-impact trauma like a fall or accident, and can affect stability and nerve function.
In technical anatomical writing, 'sacra' is the traditional Latin plural. However, 'sacrums' is commonly used and understood, especially in less formal medical contexts.
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