Bones of the Lower Limbs

Bones of the lower limbs Pelvic girdle → pelvic bones - There’s only one bone in the pelvic girdle (3 bones which fuse together during adulthood) - Ilium connects to the axial skeleton at the sacroiliac joint - Allows more stability and brings lower limbs closer to the middle of the body - Pelvic bone = flat bone (shape of the ilium) or irregular (can't be classified into the other bone shapes) - The sacrum is posterior and the cartilage is anterior - Purpose of the pelvic bones - House the reproductive organs - House the growing foetus during pregnancy 3 parts of the pelvic bone → ilium, ischium (lateral), pubic bone (medial) Acetabulum = socket for the hip joint - Socket of the ball and socket joint - There's a Y shapes pattern where the 3 bones actually meet together (3 pieces that fuse) - Have a hyaline cartilage that grows between them - ossification - Ilium (2 large mickey mouse bones) On the medial articular surface - there's an auricular surface Locks into the auricular part of the sacrum = stable joint (where it says sacroiliac joint) Pubic bone - Most anterior part of the pelvis Joint between the public joints for shock absorption and distribution of the force that goes through the upper limbs Ischium - Sitting bones - Attachment point for the hamstrings - Point downwards Pelvic inlet - The circle which distinguishes between the abdominal and pelvic organs - True pelvis = everything below the pelvic inlet (inside the ischium and pubis) --> reproductive organs and urinary bladder False pelvis = above the pelvic inlet → digestive system, intestines Pelvic outlet - You're looking at it inferiorly up - Tip of the coccyx to the ischium tuberosity - This is where the pelvic floor is Femur ● Articulates with the acetabulum and the tibia & fibula Proximal epiphysis - Medially facing head (attaches to the ball and socket joint) - Medial and lateral condyles Neck Only anatomical (no surgical) Shaft Angled towards the midline Distal epiphysis Medial and lateral condyles - Bony markings Medial and lateral epicondyles (rougher than condyles which are covered with hyaline cartilage) - Bony part with no cartilage that forms attachment point for connective tissue e.g. ligaments and capsules - - Greater and lesser trochanter - Lesser trochanter is more visible from the posterior side (opposite for tubercules) Linea aspera - Lines on the posterior side of the femur (posterior side looks rougher) - Points of attachment for fleshy muscle groups Tibia and fibula Appearance and function TIBIA FIBULA Bigger and medial Looks like a T Thinner and lateral Weight Bearing Muscle attachment point, doesn’t bear weight Proximal epiphysis - - - Shaft Medial and lateral condyles of the top of the femur articulate with the condyles of the tibia (medial and lateral) at the knee joint This is an exception to only the femur/humerus having the medial and lateral condyles because this bone has it too This is called the tibial plateau (flat plane) YES Distal epiphysis - Important for connection at the ankle joint - Articular surface on the medial sides Bony markings - YES Articular surface Medial malleolus (knobbly part on the inside of the ankle) Tibial tuberosity (anterior side) - Proximal side Foot Tarsals ● 7 bones Head - Articular surface Lateral malleolus ● ● ● Need to know the talus (ankle joint) and calcaneus (heel bone) Talus ○ Most proximal ○ Articulates with the tibia (and fibula even though this ones more on the side lateral) --> ankle joint - this is where most of the weight bearing occurs Calcaneus ○ Larger ○ Absorbs and distributes the force from the body ○ Site of lots of ligament attachment to stabilise the ankle during movement Metatarsals ● 5 long bones Phalanges ● 3 phalanges in each digit ● But the big toe has 2 digits only ● Big toe is named digit 1