The clavicle

Question 1

Bones of the Clavicle

Answer 1

• Structure: The clavicle is an elongated bone that connects the arm to the body. It has two ends:
• Sternal End: The medial end that articulates with the sternum at the sternoclavicular joint.
• Acromial End: The lateral end that articulates with the acromion of the scapula at the acromioclavicular joint.
• Diaphysis: The central shaft of the clavicle, which is slightly curved and provides strength and flexibility.

Question 2

Muscles Associated with the Clavicle

Answer 2

Several muscles attach to the clavicle, facilitating various movements of the shoulder and arm:
- Pectoralis Major: Attaches to the anterior surface of the sternal end, contributing to shoulder flexion, adduction, and internal rotation.
- Sternocleidomastoid: Originates from the sternal end and helps in neck rotation and flexion.
- Deltoid: Attaches to the acromial end and is responsible for shoulder abduction, flexion, and extension.
- Subclavius: A small muscle that stabilizes the clavicle and is located beneath it.
- Trapezius: Attaches to the acromial end and helps in shoulder elevation and retraction.

Question 3

Joints Involving the Clavicle

Answer 3

The clavicle forms two primary joints:
1. Sternoclavicular Joint:
- Type: Saddle joint.
- Articular Surfaces: The sternal end of the clavicle articulates with the sternum at the clavicular notch.
- Movements: Allows elevation, depression, protraction, retraction, and some rotation.

2. Acromioclavicular Joint:
   - Type: Plane joint.
   - Articular Surfaces: The acromial end of the clavicle articulates with the acromion of the scapula.
   - Movements: Allows for gliding movements that assist in shoulder mobility.

Question 4

Ligaments Associated with the Clavicle

Answer 4

Several ligaments stabilize the joints involving the clavicle:
- Sternoclavicular Ligament: Reinforces the sternoclavicular joint capsule.
- Interclavicular Ligament: Connects the two clavicles and stabilizes the sternoclavicular joint.
- Costoclavicular Ligament: Connects the clavicle to the first rib, limiting excessive movement of the clavicle.
- Acromioclavicular Ligament: Reinforces the acromioclavicular joint.
- Coracoclavicular Ligament: Composed of two parts (trapezoid and conoid ligaments), it connects the clavicle to the coracoid process of the scapula and provides stability to the acromioclavicular joint

Question 5

Nerves Related to the Clavicle

Answer 5

The clavicle is innervated by several nerves:
- Medial and Lateral Pectoral Nerves: Innervate the pectoralis major and minor muscles, which are attached to the clavicle.
- Suprascapular Nerve: Innervates the supraspinatus and infraspinatus muscles, which are involved in shoulder movement.
- Axillary Nerve: Innervates the deltoid muscle, which also attaches to the clavicle