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Questions and Answers
What is the number of phalanges present in one human hand?
What is the number of phalanges present in one human hand?
At what age does the secondary ossification center for the distal end of the metacarpals typically appear?
At what age does the secondary ossification center for the distal end of the metacarpals typically appear?
Which joint is found between the proximal and middle phalanges?
Which joint is found between the proximal and middle phalanges?
Which sesamoid bone is commonly found at the anterior surface of the metacarpophalangeal joint of the thumb?
Which sesamoid bone is commonly found at the anterior surface of the metacarpophalangeal joint of the thumb?
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What happens to the secondary ossification center for the thumb metacarpal around ages 2 to 3?
What happens to the secondary ossification center for the thumb metacarpal around ages 2 to 3?
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What is the most proximal part of the hand bone structure?
What is the most proximal part of the hand bone structure?
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Which carpal bone ossifies last?
Which carpal bone ossifies last?
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Which of the following bones are part of the proximal row of carpal bones?
Which of the following bones are part of the proximal row of carpal bones?
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At what age does the scaphoid bone typically start to ossify?
At what age does the scaphoid bone typically start to ossify?
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What type of joint is formed between the distal row of carpal bones and the proximal bases of the metacarpal bones?
What type of joint is formed between the distal row of carpal bones and the proximal bases of the metacarpal bones?
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Which bone articulates with the radius to form the wrist joint?
Which bone articulates with the radius to form the wrist joint?
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How many phalanges are there in one hand?
How many phalanges are there in one hand?
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What structure forms a tunnel for the flexor tendons and median nerve in the hand?
What structure forms a tunnel for the flexor tendons and median nerve in the hand?
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Study Notes
Hand Bones
- The hand bones are divided into three categories:
- Carpal bones (8 bones)
- Metacarpal bones (5 bones)
- Phalanges (14 bones)
Carpal Bones
- Arranged in two rows, each row containing four bones
- Proximal Row (lateral to medial): scaphoid, lunate, triquetrum, pisiform (on the anterior surface of the triquetrum).
- Distal Row (lateral to medial): trapezium, trapezoid, capitate, hamate (hamate bone has a projection on its palmar surface called the hook of hamate).
- The scaphoid and lunate articulate with the radius to form the wrist joint (radiocarpal joint).
- The distal row of carpal bones articulates with the metacarpals at the carpometacarpal joints.
- Intercarpal joints: between the carpal bones of the hand.
- Midcarpal joint: between the scaphoid, lunate, and triquetrum proximally, and the trapezium, trapezoid, capitate, and hamate distally.
Carpal Ossification
- Each carpal bone ossifies from a single center.
- Ossification order, excluding pisiform (clockwise direction):
- Capitate (4 months)
- Hamate (4 months)
- Triquetrum (3 years)
- Lunate (5 years)
- Scaphoid, trapezium, trapezoid (6 years)
- Pisiform ossifies at 11 years of age.
Metacarpals
- Five metacarpals numbered from lateral to medial.
- Each has a base that articulates with other metacarpals, except for the first metacarpal.
- Each metacarpal has a rounded head distally, which articulates with the proximal phalanx.
- Carpometacarpal (CMC) joints: between the distal row of carpal bones and the proximal bases of the five metacarpal bones.
- Intermetacarpal joints: between the bases of the second, third, fourth, and fifth metacarpal bones.
Phalanges
- 14 phalanges: three for each finger and two for the thumb.
- Each phalanx has a head, a shaft, and a base.
- The distal end of the distal phalanx is expanded as the tuft of the distal phalanx.
Phalangeal Articulations
- Metacarpophalangeal joint: between the metacarpals and proximal phalanges.
- Proximal interphalangeal joint: between the proximal and middle phalanges.
- Distal interphalangeal joint: between the middle and distal phalanges.
- Thumb has only a single interphalangeal joint.
Metacarpal and Phalange Ossification
- Ossify between the ninth and twelfth fetal weeks.
- Secondary ossification centers appear in the distal end of the metacarpals of the fingers at 2 years and fuse at 20 years of age.
- Thumb metacarpal and phalanges secondary centers appear at their proximal end between 2 and 3 years and fuse between 18 and 20 years of age.
Sesamoid Bones
- Small bones embedded in muscles or tendons near joint surfaces.
- Two sesamoid bones are found in the anterior surface of the metacarpophalangeal joint of the thumb in normal radiographs.
- A single sesamoid bone is present in the metacarpophalangeal joint of the little finger in 83% of radiographs.
- A single sesamoid bone is present in the interphalangeal joint of the thumb in 73% of radiographs.
- Occasionally found at other metacarpal and distal interphalangeal joints.
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Description
Test your knowledge on the anatomy of hand bones, including detailed information about carpal, metacarpal, and phalangeal bones. This quiz covers their structures, articulations, and ossification processes. Perfect for students of anatomy and biology.
