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Questions and Answers
Which bones articulate directly with the axial skeleton?
Which bones articulate directly with the axial skeleton?
Which joint is strengthened by the coracoclavicular ligament?
Which joint is strengthened by the coracoclavicular ligament?
Which bone is the longest and largest in the upper limb?
Which bone is the longest and largest in the upper limb?
Which group of bones is more mobile in the upper limb?
Which group of bones is more mobile in the upper limb?
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Which bone does not articulate directly with the axial skeleton?
Which bone does not articulate directly with the axial skeleton?
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Which ligament prevents excessive lateral and medial movements at a specific joint?
Which ligament prevents excessive lateral and medial movements at a specific joint?
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What is the anatomical neck of the humerus referred to as due to its common tendency to fracture?
What is the anatomical neck of the humerus referred to as due to its common tendency to fracture?
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Which part of the humerus forms the shoulder joint by interacting with the shoulder blade (scapula)?
Which part of the humerus forms the shoulder joint by interacting with the shoulder blade (scapula)?
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What are the two processes found in the lower extremity of the humerus?
What are the two processes found in the lower extremity of the humerus?
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Which bone in the lower arm is the main distal part of the elbow joint?
Which bone in the lower arm is the main distal part of the elbow joint?
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What type of portion does the humerus have in its lower extremity?
What type of portion does the humerus have in its lower extremity?
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Which bone contributes to the overall function and stability of the upper limb besides the humerus, radius, and ulna?
Which bone contributes to the overall function and stability of the upper limb besides the humerus, radius, and ulna?
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Study Notes
The bones of the upper limb, also known as the superior appendicular skeleton, provide the essential framework for both gross and fine motor functions of the upper limb in humans. These bones can be classified into two main groups based on their anatomical relationship with the axial skeleton: the pectoral girdle and the bones of the free part of the upper limb.
The Pectoral Girdle
The pectoral girdle, also known as the shoulder girdle, is a group of bones that directly articulate with the axial skeleton and are less mobile. It is composed of the clavicle and the scapula, which connect the upper limb to the axial skeleton through the sternoclavicular joint. The acromioclavicular joint, located between the acromion process on the scapula and the clavicle, is also strengthened by strong ligaments, especially the coracoclavicular ligament, which prevents excessive lateral and medial movements.
The Bones of the Free Part of the Upper Limb
The bones of the free part of the upper limb, which do not articulate directly with the axial skeleton, are more mobile. The majority of these bones are long bones, such as the humerus, radius, and ulna, which increase in number but decrease in size from proximal to distal. The upper limb also consists of flat, short, and sesamoid bones, such as the scapula, scaphoid, and pisiform bones, respectively.
The Humerus
The longest and largest bone of the upper limb is the humerus. It is a long bone that runs from the shoulder to the elbow and connects the scapula and the lower arm (consisting of the radius and ulna). The humerus is made up of the following parts:
- Head: A rounded area of the proximal humerus that interacts with the shoulder blade (scapula) to form the shoulder joint.
- Neck: A narrow part that connects the head to the body of the humerus.
- Body or shaft: A long, middle portion of the humerus.
- Distal: The lower area of the humerus that is closest to the elbow.
The humerus has a cylindrical upper portion and a more prismatic lower portion. Its lower extremity consists of two epicondyles, two processes (trochlea and capitulum), and three fossae (radial fossa, coronoid fossa, and olecranon fossa). The true anatomical neck and the constriction below the greater and lesser tubercles of the humerus are referred to as the surgical neck due to their tendency to commonly get fractured.
The Radius and Ulna
The radius and ulna are the two bones of the lower arm. The ulna is the main distal part of the elbow joint, while the radius composes the main proximal part of the wrist joint. Both bones have an essential role in providing a wide range of movements for the upper limb.
In conclusion, the bones of the upper limb, including the pectoral girdle and the bones of the free part of the upper limb, work together to provide the skeletal framework for both gross and fine motor functions. The humerus, radius, and ulna are the main long bones that support the upper limb, while the scapula, scaphoid, and pisiform bones contribute to the overall function and stability of the upper limb.
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Description
Test your knowledge of the bones of the upper limb, including the pectoral girdle, humerus, radius, and ulna. Learn about the anatomical structures and functions of these essential skeletal components.
