Objectives and Overview

Introduction to the Human Skeleton

The human skeleton is a dynamic structure that provides support, protection, and facilitates movement. Bones act as levers, store minerals, and protect vital organs. This guide focuses on the anatomy of the lower and upper appendicular skeleton, including bone identification and movement types.

• Identify the general gross anatomy of long bones.

• Recognize skeletal divisions and specific bones.

• Distinguish between right and left sides of bones.

• Compare male and female pelvic structures.

Bones of the Lower Extremities: Appendicular Skeleton

Pelvic Girdle

The pelvic girdle supports the weight of the upper body and connects the axial skeleton to the lower limbs. It consists of the coxal bones, which are subdivided into three regions.

• Coxal bone (hip bone):

  • Ilium (regional division)

  • Ischium (regional division)

  • Pubis (regional division)

• Pelvis: Differences exist between male and female pelvises, primarily in shape and size to accommodate childbirth in females.

Lower Limb Bones

• Femur: The longest and strongest bone in the body, forming the thigh.

• Tibia: The medial and larger bone of the lower leg.

• Fibula: The lateral and smaller bone of the lower leg.

• Patella: A sesamoid bone located in the knee, also known as the kneecap.

• Metatarsals (1-5): Long bones of the foot, numbered from medial (big toe) to lateral (little toe).

Tarsal Bones

• Calcaneus: Heel bone.

• Talus: Articulates with the tibia and fibula.

• Navicular

• Cuboid

• Cuneiforms: Medial, Intermediate, Lateral

Phalanges (1-5)

• Proximal

• Middle (except for hallux, the big toe)

• Distal

Bones of the Upper Extremities: Appendicular Skeleton

Shoulder (Pectoral) Girdle

The shoulder girdle connects the upper limb to the trunk and allows for a wide range of motion.

• Clavicle: Collarbone, acts as a strut between the scapula and sternum.

• Scapula: Shoulder blade, provides attachment for muscles.

Upper Limb Bones

• Humerus: Upper arm bone.

• Radius: Lateral bone of the forearm (thumb side).

• Ulna: Medial bone of the forearm (pinky side).

Hand Bones

• Metacarpals (1-5):

  • Proximal

  • Middle (except for pollex, the thumb)

  • Distal

• Carpals (wrist bones):

  • Scaphoid

  • Lunate

  • Triquetrum (Triquetral bone)

  • Pisiform

  • Hamate

  • Capitate

  • Trapezoid

  • Trapezium

• Phalanges (1-5):

  • Proximal

  • Middle (except for pollex, the thumb)

  • Distal

Movements of the Appendicular Skeleton

Movements in the Sagittal Plane

Movements in the sagittal plane occur forward and backward relative to the body.

• Flexion: Decreasing the angle between two bones (e.g., bending the elbow).

• Extension: Increasing the angle between two bones (e.g., straightening the knee).

• Plantar flexion: Pointing the toes downward.

• Dorsiflexion: Raising the toes upward.

Movements in the Frontal Plane

• Abduction: Moving a limb away from the midline.

• Adduction: Moving a limb toward the midline.

• Inversion: Turning the sole of the foot inward.

• Eversion: Turning the sole of the foot outward.

Movements in the Transverse Plane

• Rotation: Turning a bone around its own axis.

• Supination: Rotating the forearm so the palm faces upward.

• Pronation: Rotating the forearm so the palm faces downward.

• Horizontal Abduction: Moving a limb away from the midline in the horizontal plane.

• Horizontal Adduction: Moving a limb toward the midline in the horizontal plane.

Multiplanar Movements

• Protraction: Moving a body part forward (e.g., scapula).

• Retraction: Moving a body part backward.

• Elevation: Lifting a body part upward.

• Depression: Lowering a body part downward.

• Opposition: Movement of the thumb to touch the fingertips.

• Circumduction: Circular movement combining flexion, extension, abduction, and adduction.

Table: Comparison of Male and Female Pelvis

The following table summarizes the key differences between male and female pelvises, which are important for anatomical and clinical considerations.

Key Terms and Definitions

• Appendicular Skeleton: The portion of the skeleton that includes the limbs and girdles.

• Long Bone: Bones that are longer than they are wide, such as the femur and humerus.

• Sesamoid Bone: A bone embedded within a tendon, such as the patella.

• Phalanges: The bones of the fingers and toes.

• Flexion/Extension: Movements that decrease/increase the angle between bones.

Example: Identifying Bones in the Lab

When examining a skeletal model, students should be able to identify each bone, its side (right or left), and its anatomical features. For example, the femur can be distinguished by its head, which articulates with the pelvis, and its greater trochanter.

Additional info: Academic context and definitions have been expanded for clarity and completeness.