Upper and Lower Limb Bones

• The session is about the major bones of the upper and lower limbs, presented by Dr. Ro Nogueira, Assistant Professor of Anatomy at Bond University.

Session Learning Objectives

• Understand the major bones of the pectoral and pelvic girdles.
• Describe the bones of the upper and lower limbs and their main anatomical landmarks.
• Identify bony attachments with the axial skeleton.
• Describe factors contributing to movement and stability of the glenohumeral, hip, knee, and ankle joints.

Five Types of Bones

• Long bones.
• Short bones.
• Flat bones.
• Irregular bones.
• Sesamoid bones.

Functions of Bones

• Provide shape and support.
• Serve as sites for attachments.
• Facilitate movement.
• Protect internal organs.
• Act as storage sites for minerals.
• Support the development and storage of blood cells.

Skeletal System Numbers:

• Skull: 22 bones
• Vertebral Column: 33 bones
• Shoulder Girdle and Upper Limbs: 64 bones
• Thoracic Cage: 25 bones
• Pelvic Girdle and Lower Limbs: 62 bones
• Axial and Appendicular Skeleton: 206 bones in adults, approximately 300 in children

Appendicular Skeleton Functions:

• Facilitates movement
• Provides sites for attachments via bony projections and landmarks
• Provides articulations/joints that connect bones together via ligaments
• Hyaline cartilage prevents cortical bone erosion, bone on bone

Pectoral Girdle and Upper Limb

• A girdle is an arrangement of bones that connect the limbs (arm and leg bones) to the axial skeleton
• The pectoral girdle includes the clavicle and scapula, including associated joints like the acromioclavicular joint
• Pectoral Girdle Function: Connect upper limbs and attach the upper limb to the sternum, provides a passageway for vessels and nerves to reach the limbs

Upper Limb Bones

• Arm: Humerus
• Forearm: Radius and Ulna
• Hand: Carpal Bones, Metacarpals & Phalanges
• Function: Supports the upper limb's attachment and functions, allows body movement

Clavicle (Latin – little key)

• Horizontal, S-shaped shaft
• Functions include structural support, muscle attachment, force transmission to the axial skeleton, and strut function
• Orientation features medial end articulation with the manubrium, lateral end articulation with acromion, a smooth superior surface, and an inferior surface roughened for ligamentous attachments
• Variations in thickness and curves that can be used as a criterion for sex identification
• Development facts: 1st bone to ossify, long bone without medullary cavity

Anterior Dislocation Complications

• Shoulder instability due to damage to the inferior glenohumeral ligament (IGHL)
• Damage to the brachial plexus, commonly the axillary artery

Scapula (Latin - shoulder blade)

• Functions include structural support and arm stabilization
• Orientation: Lies over ribs 2 to 7
• Features: irregular / flat bone
• Glenoid fossa is lateral with 1/3 diameter of humeral head

Bone Markings

• Trochanter: A very large bump for muscle attachment, word means runner
• Tuberosity: An oblong, raised bump for muscle attachment and the word means bump or lump
• Tubercle: Small tuberosity

Humerus

• Head = Medial & proximal
• Olecranon fossa = posterior & distal
• Distal humerus: Olecranon fossa (posterior), Capitulum (small, lateral), Trochlea (medial) shaped like a pulley, Medial epicondyle (flexors of wrist), and Lateral epicondyle (extensors of wrist)

Glenohumeral Joint

• Synovial, multi-axial ball and socket joint. Location: head of the humerus and glenoid fossa of the scapula
• Stability: Fibrous Capsule = GLENOID LABRUM deepens joint

Lateral ligaments of the Pectoral Girdle

• Acromioclavicular ligament resists AP displacement of AC joint
• Coracoacromial ligament restricts upward displacement of the humeral head
• Coracoclavicular ligament resists rotation and vertical translation of AC joint
• Coracohumeral Ligament tightness
• Glenohumeral ligaments strengthen capsule

Forearm Bones: Ulna & Radius

• Radius: To work with the ulna at the elbow to produce pronation and supination.
• Ulna: To articulate with the humerus to form the elbow joint.

Ulna Features

• Medial forearm bone that runs parallel to the radius and contributes to the elbow joint
• Landmarks: Olecranon process, coronoid process, trochlear notch, and radial notch
• Distal End: Head of ulna, styloid process
• *Elbow extension - olecranon process rolls into the olecranon fossa of humerus.

Radius Features

• Lateral forearm bone that is curved and contributes to the elbow, proximal ulnar-radial and wrist joints
• Landmarks: Radial head and radial tuberosity
• Distal End: Styloid process, ulnar notch
• *Radial head functions to rotate against the proximal ulna = pivot joint

Elbow Joint and Ligament

• Type is synovial, hinge
• Main ligaments: Radial collateral, Ulnar collateral, and Annular ligament

Wrist and Carpal Bones

• Major bones: carpals, radius, ulna, metacarpals, phalanges
• Composed of 8 short bones located in the wrist or carpus area
• Arranged in two rows (proximal and distal), with 4 bones each
• Highly flexible due to gliding joints
• Articulation: Scaphoid and lunate articulate with radius, no bones articulate with the ulna

Carpus Bones

• Proximal row: Scaphoid, Lunate, Triquetrum, and Pisiform
• Distal row: Trapezium, Trapezoid, Capitate, and Hamate
• Mnemonic: So Long To Pinky, Here Comes The Thumb (Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium)

Metacarpals I-V (Radial to Ulnar)

• numbered from lateral to medial or thumb side
• Composed of a base, shaft & head (knuckles)
• Base articulates with distal row of carpals
• Head articulates with proximal phalanges

Phalanges I-V (Radial to Ulnar)

• Miniature long bones (fingers)
• Pollux - proximal & distal only
• II-V: consists of 3 bones proximal, middle, distal
• Each base articulates with head of proximal bone

Pelvic Girdle:

• Consists of the coxal bones (os coxae or innominate), sacrum, and coccyx.
• Contains the intestines, urinary, and reproductive organs
• Attaches the lower limb to the axial skeleton
• Provides restricted mobility and stabilizes locomotion
• Transfers body weight and attachment

Lower Limb Bones:

• Femur (thigh), patella, tibia and fibula (leg/crural), and the tarsals, metatarsals, and phalanges (foot)
• Enables humans to perform basic functions such as locomotion
• Protection, mineral storage, and production of blood cells and platelets

Pelvic Girdle & Lower Limb Function

• Load Distribution: Distributes load from the spine to the sacrum, splitting it across the sacroiliac (SI) joints and passing it to the femurs.

Pelvis Bones

• Ilium
• Ischium
• Pubis
• Sacrum
• Femur
• Coccyx

Ossification Centres:

• The ilium, ischium, and pubis attain adult size at 7-9 years
• Acetabulum fusion occurs at 20-25 years.

Pelvis bone landmarks

• Ilium - largest and most superior bone that forms the superior aspect
• Ischium - postero-inferior region
• Pubis - antero-inferior

Landmarks of the Pelvic Bone:

• Iliac crest
• Posterior superior iliac spine
• Pelvic inlet
• Sacrum
• Sacroiliac joint
• Ilium
• Ischial spine
• Acetabulum
• Pubis
• Ischium
• Pubic tubercle
• Obturator foramen
• Pubic symphysis
• Subpubic angle

Femur Orientation:

• Height is approximately four times the femoral length
• Curvature can indicate race
• The head of femur is medial
• Patellar surface is anterior

Proximal and Distal Femur

• Proximal: Head - rounded and articulates with acetabulum
• Greater & lesser trochanters: Sites for muscle attachment
• Gluteal tuberosity: Site of muscle attachment -Linea aspera: Vertical ridge on the posterior shaft
• Distal: Lateral & medial condyles - articulate with tibia and Patellar surface - articulates with patella

Stability of the Hip

• Iliofemoral Ligament: Y-shaped (anterior) – resists hyperextension.
• Pubofemoral Ligament: Triangular shaped - resists abduction.
• Ischiofemoral Ligament: Posterior - resists hyperflexion.

Patella

• Trianglular sesamoid bone
• Enclosed in quadriceps tendon that attaches thigh muscles to the tibia and improves the effective extension capacity of the quadriceps femoris

Leg Bones: Tibia and FIbula

• Medial bone of the leg that receives the weight of the body

Tibia (shin bone) features include:

• Medial & lateral condyles: Articulate with the condyles of the femur to form the tibiofemoral joint (knee!)
• Tibial tuberosity: Attachment site for anterior thigh muscles
• Medial malleolus: Bulge of ankle that articulates with the talus distally
• Lateral bone of the leg that provides muscle attachment to stabilize the ankle

Fibula features include:

• Head: Articulates with proximal aspect of tibia
• Interosseous membrane: Links fibula to tibia
• Lateral malleolus: Articulates with talus bone of foot & forms lateral bulge of ankle

Knee Ligaments

• Type of joint: synovial, hinge. Main ligaments: -Anterior cruciate ligament (ACL): resists anterior displacement of the tibia on the femur
  • Posterior cruciate ligament (PCL): resists posterior translation of the tibia on the femur.
  • Medial (Tibial) collateral ligament (MCL): resists valgus forces through all degrees of knee flexion. -Lateral (Fibular) collateral ligament (LCL): resists excess varus stress and posterior-lateral rotation of the knee
• Meniscus: a c-shaped fibrocartilaginous pad - stabilises and absorbs shock. Each knee has 2 - medial & lateral menisci

Ankle & Foot Major Bones

• Distal fibula and tibia, Tarsals, Metatarsals, and Phalanges.

Facts

• 33 joints involved in shock absorption, flexibility, and balance of body
• Ankle Joints
  • Fibula
  • Tibia
  • Malleolus
  • Tarsal
  • Calcaneus

Tarus Bones

• Composed of 7 Tarsal bones, 5 Metatarsal bones and 14 Phalanges (same arrangement as bones of the hand)

The Tarus Bones

• 7 bones on posterior half of foot which body weight is primarily carried by talus and Calcaneus
• Calcaneus forms heel of foot, point of attachment point for Calcaneal (Achilles) tendon

Metatarsals

• Five small long ones radiating from tarsus (1-5)
• Distal heads artículate with proximal phalanges

Phalanges

• 14 individual bones and the toe is assigned roman numerals (1-5)
• Function is to provide balance stability stability

Arches of the Foot:

• Lateral longitudinal and medial longitudinal arch

Lateral Longitudinal Arch

• Keystone: Cuboid
• Bony components: Calcaneus and Cuboid and Metatarsals 4-5

Medial Longitudinal Arch

• Keystone:
• Bony components: Calcaneus; Talus and Navicular
• MEDIAL ARCH is HIGHER than LATERAL ARCH

Ankle and Foot Joints

• The key joints in the Ankle and Foot are: Talocrural, Subtalar and Mldtarsal

Ankle Ligaments

• Lateral = Weaker than medial is prevents inversion
• Meda Ligaments prevent Eversión