Anatomy of Pelvis, Lower Limb Bones, and Muscles
Pelvic Girdle Anatomy
Bones of the Pelvic Girdle
The pelvic girdle bones are the innominate (or iliac) bones, the sacrum, and the coccyx.
Pelvic Girdle Joints
The joint connecting the two pelvic bones is called the symphysis pubis.
Features of the Ilium
The iliac or innominate bone is formed from the fusion of three bones: the ilium, pubis, and ischium.
Iliac Crest Function
The iliac crest serves as an insertion point for the abdominal muscles.
Lower Limb Bone Anatomy
The Femur
Femur Articulations
The femoral head articulates with the hip bone at the acetabulum.
The condyles and trochlea of the femur articulate with the tibia.
The condyles and trochlea of the femur articulate with the facet joints (tibial plateaus) on the tibia.
Femur Muscle Attachments
The greater trochanter and lesser trochanter of the femur serve as insertion points for muscles of the thigh and buttocks.
Thigh muscles are inserted along the linea aspera of the femur.
The Tibia
Tibia Location and Palpation
In the leg, the tibia is located towards the medial (interior) side.
The crest of the tibia can be palpated externally (anteriorly) along the leg.
Tibia Articulations
The articulation of the tibia and femur is facilitated by the concave shape of the tibial plateaus (the top surface of the tibia’s condyles).
The distal epiphysis of the tibia articulates with the talus bone of the tarsus.
The Fibula
Fibula Articulations
The fibula articulates superiorly (upward) with the tibia and inferiorly (downward) with both the tibia and the talus bone of the tarsus.
Lateral Malleolus
The outer ankle is also known as the lateral malleolus (part of the fibula).
Foot Bones
Tarsal Bones
The tarsal bones are located in the posterior part of the foot. They consist of the calcaneus, talus, cuboid, navicular, and the three cuneiform bones.
Metatarsals and Phalanges
In the foot, the metatarsal bones articulate with the cuneiform and cuboid bones at their base and with the proximal phalanges through their distal heads.
The phalanges of the toes are named as follows: proximal phalanx, middle phalanx (or intermediate phalanx), and distal phalanx.
Muscle Anatomy and Function
Myology: The Study of Muscles
Myology is the science that deals with the study of muscles.
Muscle Blood Supply
Muscles require a rich blood supply because they need a significant amount of oxygen and nutrients (food) for energy and function.
Muscle Connective Tissues
Muscles are covered and organized by connective tissue membranes:
- Endomysium: Protects the individual muscle fiber.
- Perimysium: Protects a bundle of muscle fibers (fascicle or primary bundle).
- Epimysium: Protects the entire muscle (secondary bundle).
Muscle Coloration
Muscles appear red because they contain a pigment called myoglobin, which stores oxygen.
Muscle Innervation
Muscles have nerve endings because the central nervous system transmits signals (including motor commands and sensory information) to and from them.
Main Muscle Groups
The three main types of muscle tissue are:
- Skeletal muscle (striated)
- Cardiac muscle (striated)
- Smooth muscle (non-striated)
Similarities and Differences
Similarities and differences between skeletal and cardiac muscles (details not provided in original text).
Differences from Smooth Muscle
Reasons why smooth muscles are different from skeletal and cardiac muscles (details not provided in original text).
Muscle Protein Filaments
The main proteins that make up the myofilaments are:
- Thin myofilaments: Actin, tropomyosin, and troponin.
- Thick myofilaments: Myosin.
Myofilaments are responsible for muscle contraction and movement.
Aponeurosis and Fascia
Aponeurosis (or fascia) is a very strong and resistant type of connective tissue membrane.
Aponeurosis plays several roles, including:
- Wrapping and compartmentalizing individual muscles or groups of muscles.
- Serving as insertion points for muscle fibers.
- Connecting muscles to bones or other structures.