Pelvic Girdle and Related Bones

Study Notes

Pelvic Girdle

Responsible for attaching the lower limbs to the axial skeleton
Transfers weight from the upper body to the lower limbs
Supports organs in the pelvic cavity
Connected via the strongest ligaments in the body
Forms the acetabulum, a deep hemisphere socket that articulates with the thigh bone (femur)
Acetabulum: is formed when the 3 bones of the pelvic girdle fuse

Os Coxae

Consists of three bones: ilium, ischium, and pubis
Ilium: Thickened superior margins called iliac crests. Spines act as attachment points for muscles in the trunk, hip, and thigh.
Ischium:
Pubis: Two bones joining at the pubic symphysis. Narrower in males, broader in females.

Femur

The largest, thickest, and strongest bone in the body
It has a ball-like head that attaches to the acetabulum
The proximal end articulates with the hip
The distal end (lateral and medial condyles) articulates with the tibia

Patella

A triangular, sesamoid bone that protects the kneecap
Assists with the quadriceps muscles in bending and straightening the leg
Susceptible to dislocation

Tibia

Referred to as the "shin bone"
Receives weight from the femur
Is the taller of the two bones in the lower leg
The medial malleolus connects with the ankle joint

Fibula

Referred to as the "calf bone"
Doesn't bear weight
Shorter than the tibia
The lateral malleolus connects with the ankle joint

Foot

Composed of three sections: Tarsus, Metatarsus, and Phalanges
Tarsus: Includes seven tarsal bones:
- Calcaneus: Forms the heel
- Talus: Articulates with the tibia and fibula
Metatarsus: Five small, long bones called metatarsals
Phalanges: 14 bones making up the toes
- Three bones per phalange, except for the hallux (big toe) which has only two.

Pectoral Girdle

Consists of two bones: the clavicle (anteriorly) and scapula (posteriorly)
Provides attachment points for muscles that connect the scapula to the thorax and vertebral column
Allows for the attachment of the upper limbs
Demonstrates light weight, high flexibility, and mobility, unlike other areas of the body.

Clavicle

Known as the "collar bone"
The medial, sternal end is cone-shaped and attaches to the manubrium
The lateral, acromial end is flattened and attaches to the acromion of the scapula.

Scapula

Referred to as the shoulder blades
Has three borders
The glenoid cavity articulates with the humerus
The acromion articulates with the clavicle
Serves as an attachment point for numerous muscles, contributing to the formation of the shoulder joint
Secures the upper limbs to the trunk

Humerus

The proximal end has a hemispherical head that fits into the glenoid cavity
The distal end has two condyles:
- Medial trochlea: Shaped like a pulley
- Lateral capitulum: Ball-shaped, articulates with the radius (proximal end)
Lies laterally (thumb side) in anatomical position

Radius

Lies laterally (thumb side) in anatomical position
The proximal end articulates with the humerus
The distal end articulates with the carpal bones
Articulates with the ulna at the radio-ulnar joint

Ulna

Lies medially (pinky side) in anatomical position
Forms a joint with the humerus at the distal ends
The distal ends form joints with the wrist

Carpus

Referred to as the wrist
Composed of eight small, short bones called carpals

Metacarpus

Referred to as the palm
Composed of five long bones, numbered 1-5 (thumb to little finger)

Phalanges

Referred to as the fingers
Composed of long bones, numbered 1-5 (thumb to little finger)
Each finger has three phalanges, except for the thumb (pollex), which only has two.

Description

This quiz covers key anatomical features of the pelvic girdle, including the os coxae structure and the relationship with the femur and patella. Test your knowledge on the components and functions of this critical part of the human skeleton. Understand the importance of weight transfer and muscle attachment in locomotion.