Lesson 4 of 14 · Yoga & anatomy

Bones, limbs & girdles

Make sense of the 206-bone map.

Axial and appendicular skeletons, bone functions, hands, feet, limb counts and the shoulder and pelvic girdles.

Notes: Daniel Fewtrell · Edited 14 September 2026
Educational study material · No named teacher review recorded

01 · Study

Two divisions, one skeleton

80Axial bones

126Appendicular bones

206Conventional adult total

Osteology is the study of bones. The axial skeleton forms the central framework: skull and associated bones, vertebral column and rib cage. The appendicular skeleton consists of the limbs and their attachment girdles.

Labeled whole-skeleton views identifying major bones and distinguishing the axial skeleton from the appendicular skeleton. — **The human skeleton**The human skeleton — OpenStax, Anatomy and Physiology, CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction Source · CC BY 4.0Select the image for a full-size view.

Further reading: OpenStax · Skeletal divisions ↗

02 · Study

Why children have a different count

The notes say a child has 340 bones and suggest fusion finishes at ages 20–22. Those should not be used as universal facts. The number depends on age and what is being counted; separate developing parts fuse over time, and different bones mature at different ages.

206 is the conventional adult teaching count. Individual anatomical variation means it is not an exact count for every adult.

Further reading: OpenStax · Skeletal divisions ↗

03 · Study

What bones do

The first three functions come directly from the notes. The remaining three complete the usual introductory explanation. Bone is living tissue, not an inert framework.

Function	Example
Support	A framework for the body
Movement and locomotion	Levers acted on by muscles
Protection	The skull around the brain
Mineral storage	Calcium and phosphate
Blood-cell production	Red bone marrow
Energy storage	Fat in yellow marrow

Further reading: OpenStax · Functions of the skeletal system ↗

04 · Study

Upper limb: 30 bones on each side

The 27 bones of one hand, including its wrist, are 8 + 5 + 14. Adding the humerus, radius and ulna gives the 30-bone upper limb. The shoulder girdle is counted separately.

Bone or group	One side	Where
Humerus	1	Upper arm
Radius + ulna	2	Forearm
Carpals	8	Wrist
Metacarpals	5	Palm
Phalanges	14	Fingers and thumb
Total	30	60 across both upper limbs

Labeled hand and wrist diagram showing the carpals, metacarpals and finger phalanges. — **Bones of the hand and wrist**Bones of the hand and wrist — OpenStax, Anatomy and Physiology, CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction Source · CC BY 4.0Select the image for a full-size view.

Further reading: OpenStax · Bones of the upper limb ↗

05 · Study

Lower limb: 30 bones on each side

One foot contains 7 + 5 + 14 = 26 bones in the conventional count. Add femur, patella, tibia and fibula to reach 30 for the limb.

Bone or group	One side	Where
Femur	1	Thigh
Patella	1	Kneecap
Tibia + fibula	2	Leg below the knee
Tarsals	7	Ankle and rear/midfoot
Metatarsals	5	Forefoot
Phalanges	14	Toes
Total	30	60 across both lower limbs

Labeled foot diagrams showing the tarsals, metatarsals and toe phalanges. — **Bones of the foot**Bones of the foot — OpenStax, Anatomy and Physiology, CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction Source · CC BY 4.0Select the image for a full-size view.

Further reading: OpenStax · Bones of the lower limb ↗

06 · Study

The girdles connect the limbs

Each adult hip bone forms from the ilium, ischium and pubis. The bony pelvis also includes the sacrum and coccyx; these belong to the axial skeleton, not the two-bone pelvic-girdle count.

Girdle	Adult bones	Both sides
Pectoral / shoulder girdle	One clavicle and one scapula per side	4
Pelvic girdle	One hip bone per side	2

Further reading: OpenStax · Skeletal divisions ↗ · OpenStax · Pelvic girdle and pelvis ↗

07 · Study

Use the map without forcing the shape

Knowing the names helps you follow instructions and locate a question. It does not tell you how far a particular person should fold, turn out a foot or move a shoulder. Joint shape and movement capacity vary. Bring the map into conversation with sensation and a teacher’s guidance.

08 · Study

Axial skeleton: reconciling the 80-bone count

IMG_1589 uses “skull = 29” by including the ear ossicles and hyoid. That is a broader head-associated grouping, not 29 bones in the skull proper. The notation can be understood without losing the standard anatomical distinction.

Group	Conventional adult count	Clarification
Skull proper	22	8 cranial + 14 facial bones
Auditory ossicles	6	3 per middle ear
Hyoid	1	Separate from the skull proper
Vertebral column	26	24 separate vertebrae + sacrum + coccyx
Ribs	24	12 pairs
Sternum	1	Breastbone
Total	80	22 + 6 + 1 + 26 + 24 + 1

Further reading: OpenStax · Skeletal divisions ↗

09 · Study

Five spinal regions, two ways of counting

The notebook’s “26 vertebrae” should be read as 26 adult bones in the column, rather than 26 separate mobile vertebrae. The sacrum and coccyx contain fused segments. A typical developmental count is 33 vertebral segments; anatomical variation occurs. Fusion is a developmental process, not a single event at one birthday.

Region	Label	Adult count
Cervical	C1–C7	7
Thoracic	T1–T12	12
Lumbar	L1–L5	5
Sacrum	5 fused sacral segments	1 bone
Coccyx	Usually 4 fused segments; variable	1 bone

Labeled views of the vertebral column showing cervical, thoracic, lumbar, sacral and coccygeal regions and the spinal curves. — **The vertebral column**The vertebral column — OpenStax, Anatomy and Physiology, CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction Source · CC BY 4.0Select the image for a full-size view.

Further reading: OpenStax · Vertebral column ↗

10 · Study

Ribs and girdles: useful refinements

Rib pairs 1–7 are true ribs, connected to the sternum through their own costal cartilages.
Pairs 8–10 connect indirectly through the cartilage above.
Pairs 11–12 are floating ribs with no anterior sternal attachment. They are also a subset of false ribs in standard classification.
The shoulder girdles contain two clavicles and two scapulae in total.
Ilium, ischium and pubis fuse into each adult hip bone. “Iliac” and “pubic” are descriptive forms; ilium and pubis are the bone names.

Labeled pelvic-girdle diagram showing the hip bones, sacrum, coccyx and major bony landmarks. — **The bony pelvis**The bony pelvis — OpenStax, Anatomy and Physiology, CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction Source · CC BY 4.0Select the image for a full-size view.

Further reading: OpenStax · Thoracic cage ↗

From notebook to page

Drawn from the anatomy, upper-limb and blurred lower-limb pages, plus the hand-and-foot calculation. The lower-limb table is a standard anatomical reconstruction, not a claim that every word in the blurred photograph is legible. The hip-girdle heading has been completed with explanatory material.

Spelling has been standardised and explanations added. Traditional teaching cues, anatomical facts and uncertain handwriting are distinguished in the text. These pages support learning alongside appropriate teaching.