7.2.7 Pelvic Girdle and Lower Limb

• Made up of three units:
• These form coxa.
• The two halves of the pelvic girdle are joined at the pubic symphysis.
• A cavity called acetabulum is also present.

• Femur — thighbone; long bone with head, which fits into the acetabulum.
• Patella — kneecap; embedded in a long tendon which runs over the knee joint.
• Tibia — shin bone; large bone in the leg.
• Fibula — outer bone; thin bone joins the tibia just below the knee joint and just above the ankle.
• Tarsal — made of seven bones which are tightly attached to form the ankle.
• Metatarsal — five bones which articulate with the tarsal and phalanges to form the sole of the foot.
• Phalanges — small bones which make up the toes.
• Each toe of the foot possesses three phalanges except big toe; which comprises of two phalanges.

Summary Table of Human Skeleton

Intermediate Level

Divisions of Human Skeleton

Head Bones

Vertebral Column

Rib Cage

Formula / Mathematical Form

Not applicable to this topic.

Solved Example

Not applicable to this topic (descriptive topic).

Important Points

• 1. Human skeleton consists of 206 bones.
• 2. Primarily divided into axial and appendicular skeleton.
• 3. Axial skeleton includes skull, vertebral column, rib cage.
• 4. Appendicular skeleton includes pectoral girdle, pelvic girdle, forelimbs, hind limbs.
• 5. Head contains 29 bones.
• 6. Cranial bones form cranium.
• 7. There are 8 cranial bones.
• 8. There are 14 facial bones.
• 9. There are 3 pairs of ear ossicles.
• 10. Hyoid bone is a single bone at the base of skull.
• 11. Vertebral column consists of 33 vertebrae.
• 12. There are 7 cervical vertebrae.
• 13. There are 12 thoracic vertebrae.
• 14. There are 5 lumbar vertebrae.
• 15. There are 5 sacral vertebrae.
• 16. There are 4 coccygeal vertebrae.
• 17. Rib cage consists of 12 pairs of ribs.
• 18. True ribs: 7 pairs.
• 19. False ribs: 3 pairs.
• 20. Floating ribs: 2 pairs.
• 21. Pectoral girdle consists of clavicles and scapulae.
• 22. Pelvic girdle consists of ileum, ischium, and pubis.
• 23. Forelimb consists of humerus, radius, ulna, carpals, metacarpals, phalanges.
• 24. Hind limb consists of femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.

Remember

• - 206 bones = total in human skeleton
• - Axial skeleton = central axis; skull, vertebral column, rib cage
• - Appendicular skeleton = appendages; pectoral girdle, pelvic girdle, forelimbs, hind limbs
• - **Skull** = 29 bones
• - **Cranial bones** = 8
• - **Facial bones** = 14
• - **Ear ossicles** = 3 pairs
• - **Hyoid bone** = 1
• - Vertebral column = 33 vertebrae
• - **Cervical** = 7
• - **Thoracic** = 12
• - **Lumbar** = 5
• - **Sacral** = 5
• - **Coccygeal** = 4
• - **Rib cage** = 12 pairs
• - True ribs = 7 pairs
• - False ribs = 3 pairs
• - Floating ribs = 2 pairs

Common Mistakes

• 1. Confusing axial and appendicular skeleton — Axial = central axis; appendicular = appendages.
• 2. Mixing up the number of bones — 206 total.
• 3. Forgetting the number of vertebrae — 33 total.
• 4. Mixing up the types of ribs — True, false, floating.
• 5. Confusing the number of cranial and facial bones — 8 cranial; 14 facial.
• 6. Forgetting the hyoid bone — Single bone at the base of skull.
• 7. Mixing up the bones of the forelimb — Humerus, radius, ulna, carpals, metacarpals, phalanges.
• 8. Mixing up the bones of the hind limb — Femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.
• 9. Forgetting the pectoral and pelvic girdles — Pectoral = clavicles and scapulae; pelvic = ileum, ischium, pubis.
• 10. Mixing up the number of phalanges — Each finger has three phalanges except thumb (two); each toe has three phalanges except big toe (two).

Quick Revision

Human skeletal system consists of 206 bones which are primarily divided into two division i.e., axial skeleton and appendicular skeleton. Axial skeleton includes those skeletal parts which are present along the central axis of the body, like skull, vertebral column and rib cage. Appendicular skeleton includes those skeletal parts which are present in appendages (arms and legs). These are pectoral girdle, pelvic girdle, forelimbs and hind limbs. Head contains 29 bones which are divided into four divisions i.e., cranial bones, facial bones, ear ossicles and hyoid bone. The vertebral column in human being consists of thirty-three vertebrae. The vertebrae may be divided into following five groups: (a) Cervical vertebrae - 7, (b) Thoracic vertebrae - 12 (c) Lumbar vertebrae - 5 (d) Sacral vertebrae - 5 (e) Coccygeal vertebrae - 4. The rib cage consists of twelve pairs of ribs. The seven pairs of ribs that attach directly to the sternum are called true ribs. The 8th, 9th and 10th are called false ribs, as these three pairs of ribs are attached to the sternum by means of common costal cartilage. 11th and 12th pairs of ribs are known as floating ribs, because they do not attach to the sternum. Pectoral girdle consists of a pair of clavicles and a pair of scapula. Upper limb or Forelimb consists of humerus, ulna, radius, carpals, metacarpals and phalanges. The pelvic girdle is made up of three units the ileum, ischium and pubis which form coxa. Lower limb or Hind limb consists of femur, patella, tibia, fibula, tarsal, metatarsal and phalanges.

60-Second Revision

• 206 bones = total in human skeleton
• Axial skeleton = central axis; skull, vertebral column, rib cage
• Appendicular skeleton = appendages; pectoral girdle, pelvic girdle, forelimbs, hind limbs
• Skull = 29 bones
• Cranial bones = 8
• Facial bones = 14
• Ear ossicles = 3 pairs
• Hyoid bone = 1
• Vertebral column = 33 vertebrae
• Cervical = 7
• Thoracic = 12
• Lumbar = 5
• Sacral = 5
• Coccygeal = 4
• Rib cage = 12 pairs
• True ribs = 7 pairs
• False ribs = 3 pairs
• Floating ribs = 2 pairs
• Warning: Axial skeleton = central axis; appendicular skeleton = appendages

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• 7. Support and Movement

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• 7.3 JOINTS

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