The appendicular skeleton is the part of the skeleton that is made up of the bones of the limbs, shoulder girdle, and pelvic girdle. It is distinguished from the axial skeleton, which is made up of the bones of the skull, vertebral column, and rib cage. The appendicular skeleton is critical to movement, as it provides the structural support for the muscles that control the limbs. In this article, we will explore the bones of the appendicular skeleton in detail.
Bones of the Upper Limbs
The upper limbs consist of the arm, forearm, wrist, and hand. There are 30 bones in total in the upper limb.
Arm
The arm is made up of a single bone, the humerus. The humerus is the longest and largest bone in the upper limb. At the distal end of the humerus are two projections, the medial and lateral epicondyles, which serve as anchor points for forearm muscles.
Forearm
The forearm is made up of two bones, the radius and the ulna. The radius is located on the lateral side of the forearm, while the ulna is on the medial side. The two bones articulate at both the elbow and wrist joints.
Wrist and Hand
The wrist consists of eight small bones, known as the carpal bones. The bones of the hand are divided into three groups – the metacarpals, or the bones of the palm, and the phalanges, which compose the fingers.
Bones of the Lower Limbs
The lower limbs consist of the thigh, leg, ankle, and foot. There are 30 bones in total in the lower limb.
Thigh
The thigh is made up of a single bone, the femur. The femur is the longest and strongest bone in the body. It articulates with the hip bone at the hip joint and with the tibia bone at the knee joint.
Leg
The leg is made up of two bones, the tibia and the fibula. The tibia is the larger of the two bones and is located on the medial side of the leg. The fibula is located on the lateral side of the leg and is much smaller than the tibia.
Ankle and Foot
The ankle joint is composed of three bones – the talus, the calcaneus, and the navicular – and is responsible for movement between the leg and foot. The foot is divided into three groups of bones – the tarsals, metatarsals, and phalanges, which compose the toes.
Bones of the Shoulder Girdle and Pelvic Girdle
Shoulder Girdle
The shoulder girdle consists of two bones, the scapula and the clavicle. The scapula, also known as the shoulder blade, is a large, flat bone on the back of the thorax. The clavicle, or collarbone, runs horizontally across the front of the thorax and connects the scapula to the sternum.
Pelvic Girdle
The pelvic girdle consists of two hip bones, which are also known as the os coxae. Each hip bone is composed of three bones – the ilium, the ischium, and the pubis. The hip bones are fused together at the midline to form the sacrum.
Functions of the Appendicular Skeleton
The appendicular skeleton has several important functions. Firstly, it provides a framework for the muscles that control limb movement. Secondly, it protects important organs such as the heart and lungs in the thorax and the reproductive organs in the pelvis. Lastly, it serves as a reservoir for calcium and phosphate ions, which are important for bone and muscle health.
Disorders of the Appendicular Skeleton
Like all parts of the body, the appendicular skeleton is susceptible to a range of disorders. Some of the most common disorders include fractures, which occur when a bone is broken, and arthritis, which is inflammation of the joints. Other disorders include osteoporosis, which is a weakening of the bones due to calcium loss, and osteogenesis imperfecta, which is a genetic disorder that causes brittle bones.
Conclusion
The appendicular skeleton is comprised of the bones of the limbs, shoulder girdle, and pelvic girdle. It is responsible for movement, protection of internal organs, and nutrient storage. Understanding the bones that make up the appendicular skeleton is important for maintaining overall body health.
Most Common Questions and Answers Related to ‘What Does the Appendicular Skeleton Consist of’
- Q: What is the appendicular skeleton?
- A: The appendicular skeleton is the part of the skeleton that is made up of the bones of the limbs, shoulder girdle, and pelvic girdle.
- Q: How many bones are there in the appendicular skeleton?
- A: There are 126 bones in the appendicular skeleton.
- Q: What is the function of the appendicular skeleton?
- A: The appendicular skeleton provides a framework for movement, protection of internal organs, and nutrient storage.
- Q: What are some common disorders of the appendicular skeleton?
- A: Some common disorders of the appendicular skeleton include fractures, arthritis, osteoporosis, and osteogenesis imperfecta.
References
1. Saladin, K. S. Anatomy & Physiology: The Unity of Form and Function. McGraw-Hill Education, 2018.
2. Tortora, G. J. and Derrickson, B. Principles of Anatomy and Physiology. John Wiley & Sons, 2017.
3. Netter, F. H. Atlas of Human Anatomy. Saunders, 2014.