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shoulder

Primary Information
Secondary Information

Definition

A shoulder is the articulation between the arm and the trunk. It is a ball-and-socket joint, which means that the humerus (upper arm bone) fits into a socket in the scapula (shoulder blade). This allows for a wide range of motion, including flexion, extension, abduction, adduction, internal rotation, and external rotation.

The shoulder joint is stabilized by a number of ligaments, including the coracohumeral ligament, the glenohumeral ligament, and the acromioclavicular ligament. The muscles that control the shoulder joint include the deltoid, the supraspinatus, the infraspinatus, the teres minor, and the subscapularis.

The shoulder is a very mobile joint, but it is also prone to injury. Common shoulder injuries include rotator cuff tears, shoulder impingement syndrome, and shoulder instability.

How can the word be used?

The soldier braced his shoulder against the door.

shoulder

Different forms of the word

Noun:

  • the part of the body between the neck and the arm.
  • a sloping ridge or projection.
  • a responsibility or burden.

Verb:

  • to take on a responsibility or burden.
  • to support or help someone.
  • to push or shove someone.

Etymology

The word "shoulder" comes from the Old English word "sculdor", which also means "shoulder".

The first recorded use of the word "shoulder" in English was in the 8th century.

The word "shoulder" is an Old English word, and it is related to the German word "Schulter" and the Dutch word "schouder".

Question

What three bones make up your shoulder?

AQA Science Exam Question and Answer

Question:

Explain the structure and function of the shoulder joint, highlighting its unique range of motion and the importance of its anatomical components in facilitating various arm movements.

Answer:

The shoulder joint is a complex and highly mobile ball-and-socket joint that enables a wide range of arm movements. It consists of the head of the humerus (upper arm bone) and the shallow socket of the scapula (shoulder blade), which together create the glenohumeral joint.

The shoulder's unique range of motion allows actions like flexion, extension, abduction, adduction, internal and external rotation, and circumduction. This versatility is due to the joint's relatively shallow socket, which provides flexibility but also makes it susceptible to instability and dislocation.

The shoulder joint is reinforced by ligaments, tendons, and muscles. The rotator cuff muscles, including the supraspinatus, infraspinatus, teres minor, and subscapularis, play a crucial role in stabilising the joint and controlling its movements. Ligaments like the coracoclavicular ligaments and the acromioclavicular joint provide additional support.

Despite its remarkable range of motion, the shoulder joint is prone to injuries and conditions like dislocations, rotator cuff tears, and impingements. Proper care, strengthening exercises, and maintaining good posture are essential for preventing and managing such issues.