Bones of the Lower Limbs and Pelvic Girdle

Bones of the Lower Limbs

• The lower limb consists of the femur (thigh), tibia and fibula (leg), tarsals (ankle), metatarsals (foot), and phalanges (toes)

Pelvic Girdle

• Composed of two hip bones, sacrum, and coccyx
• Hip bones unite anteriorly with each other at symphysis pubis
• Articulates posteriorly with the sacrum
• Formed by hip bones, sacrum, and coccyx
• Divided into two regions: true (lesser) pelvis and false (greater) pelvis

Hip Bone

• Composed of ilium, ischium, and pubis
• Acetabulum is a deep hemispherical socket on the lateral pelvic surface

Sex Difference of the Pelvis

• Pelvic inlet is oval in female and heart-shaped in male
• Ischial spines don't project medially in the pelvis in female
• Pubic angle is 80-90 in female and 50-60 in male

The Lower Limb

• Carries the entire weight of the erect body
• Bones of the lower limb are thicker and stronger than those of the upper limb
• Divided into three segments: thigh, leg, and foot

Femur

• Is the largest and strongest bone of the body

Appendicular Skeleton

• The primary function is movement
• Includes bones of the upper and lower limbs
• Girdles attach the limbs to the axial skeleton

Skeleton of the Upper Limb

• Consists of the shoulder girdle, arm, forearm, and bones of the hand

Pectoral Girdle

• Consists of two clavicles and two scapulae
• Provides attachment for many muscles that move the upper limb
• Girdle is very light and upper limbs are mobile
• Only clavicle articulates with the axial skeleton
• Socket of the shoulder joint (glenoid cavity) is shallow

Clavicle

• Provides attachment for muscles
• Holds the scapulae and arms laterally
• Transmits compression forces from the upper limbs to the axial skeleton

Scapula

• Has three surfaces: costal, dorsal, and spinous
• Dorsal surface is divided by the spine into supra-spinatus and infra-spinatus fossa
• Angles of the scapula include superior, lateral, and inferior angles

Humerus

• Is the largest bone in the upper limb
• Articulates superiorly with the scapula and inferiorly with the radius and ulna
• Has upper and lower ends and a shaft

Patella

• Triangular sesamoid bone
• Imbedded in the tendon that secures the quadriceps muscles
• Protects the knee anteriorly

Leg

• Refers to the region of the lower limb between the knee and the ankle
• Composed of the tibia and fibula
• Tibia articulates with the femur at the superior end and forms the knee joint
• Tibia articulates with the talus at the inferior end and forms the ankle joint
• Fibula does not contribute to the knee joint but stabilizes the ankle joint

Fibula

• The fibula has upper and lower ends and a shaft
• The upper end has a styloid process, head, neck, and tibial notch

Bones of the Foot

• Consist of tarsals, metatarsals, and phalanges
• There are 7 tarsal bones, 5 metatarsal bones, and 14 phalanges
• First metatarsal supports body weight