ANHB1101__Bones__Joint___Movement_

Introduction to the Skeletal System

• The skeletal system provides the framework for the body.

• Knowledge of individual bones aids in locating other anatomical features.

• Example: Radial artery and ulna nerve are named for their proximity to the radius and ulna, respectively.

• Understanding bone names helps in studying comparative anatomy and evolutionary relationships.

Types of Bones

• Classification by Shape:

  • Long Bones: Greater length than width; variable in size.

  • Short Bones: Cube-shaped; nearly equal in length and width.

  • Flat Bones: Thin bones providing protection and muscle attachment.

  • Irregular Bones: Complex shapes.

  • Sesamoid Bones: Develop in tendons subjected to friction, tension, and stress.

Divisions of the Skeletal System

• Axial Skeleton:

  • Primary function: Protection of internal organs.

• Appendicular Skeleton:

  • Primary function: Movement.

• Musculoskeletal System: Bones, muscles, and joints work together for movement.

Key Terms and Word Roots

• Common Terms:

  • appendic: to hang onto

  • sesamoid: like a sesame seed

  • mand: to chew

  • tempor: temple

  • ab/ad: away/towards

  • duc: to lead/carry

  • circum: around

  • flex/extens: to bend/draw out

  • pro/re: forward/back

  • tract: to pull in/inward

  • e/vert: outward/to turn

  • pecto/pelvis: chest/basin

  • arthrosis: articulation of bones (joint)

  • planto: sole of the foot

Movements at Joints

• Joints allow for specific movements that occur in particular planes of motion:

  • Flexion: Movement towards the ventral; decreases joint angle.

  • Extension: Movement towards the dorsal; increases joint angle.

  • Hyperextension: Movement past the anatomical position.

  • Abduction: Movement away from the midsagittal plane.

  • Adduction: Movement towards the midsagittal plane.

  • Rotation: Bone spins on its longitudinal axis.

  • Circumduction: Distal end describes a circle while proximal end remains stationary.

  • Pronation/Supination: Forearm movements turning palm up or down respectively.

  • Dorsiflexion/Plantarflexion: Foot movements with toes up or down.

  • Elevation/Depression: Raising or lowering body parts.

  • Eversion/Inversion: Foot movements raising medial or lateral sides.

  • Protraction/Retraction: Movement anteriorly or posteriorly.

Axial Skeleton

• Consists of bones around the body's longitudinal axis, including:

  • Skull: Cranium and facial bones.

    • Frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones.

    • Functions in protection of the brain and support of facial structure.

  • Vertebral Column: Composed of cervical (7), thoracic (12), lumbar (5), sacral (5), and coccygeal (4) vertebrae.

    • Functions:

      • Support head and trunk.

      • Protect spinal cord.

      • Attachment point for muscles and ribs.

Appendicular Skeleton

• Includes bones of upper and lower limbs and girdles attaching them to axial skeleton:

  • Pectoral Girdles: Connect upper limbs, composed of clavicle and scapula.

  • Pelvic Girdle: Connects lower limbs, formed by two fused coxal bones and sacrum.

• Functions primarily in movement and mobility.

Evolutionary Relationships

• Comparative anatomy suggests shared ancestral traits among primates.

• Features such as a vestigial coccyx in apes indicate evolutionary links.

• Differences in skull and jaw positioning provide insights into human evolution and development.

Career Pathways in Anatomy

• Potential outcomes for studying anatomy:

  • Careers in teaching, research, anatomy, physiotherapy, medicine, nursing, paramedicine, occupational therapy, and occupational health and safety.

• Level 2 units to consider for further study include Human Structure and Development, Human Organs and Systems, Human Neurobiology, Animal Form and Function, and Biomechanics in Sports and Exercise.

Axial Skeleton

Consists of bones around the body's longitudinal axis, including:

• Skull: Composed of cranial and facial bones.

  • Cranial Bones: Protect the brain and support the structure of the head. Includes:

    • Frontal Bone: Forehead region, forms the upper part of the eye sockets.

    • Parietal Bones (2): Located on the sides and roof of the skull.

    • Temporal Bones (2): Located below the parietal bones; involved in hearing and balance.

    • Occipital Bone: Forms the lower back part of the skull; contains the foramen magnum for spinal cord passage.

    • Sphenoid Bone: Located in the middle of the skull; helps form the eye sockets and temple.

    • Ethmoid Bone: Located between the nasal cavity and the orbits; contributes to the nasal septum and eye sockets.

  • Facial Bones: Support facial structure and house organs of sight, taste, and smell. Includes:

    • Maxilla (2): Upper jawbone; forms the hard palate.

    • Mandible: Lower jawbone; the only movable skull bone.

    • Zygomatic Bones (2): Cheekbones; form the sides of the eye sockets.

    • Nasal Bones (2): Small bones forming the bridge of the nose.

    • Lacrimal Bones (2): Smallest bones in the face; form part of the eye socket.

    • Palatine Bones (2): Form the back part of the hard palate.

    • Inferior Nasal Concha (2): Form part of the lateral wall of the nasal cavity.

    • Vomer: Forms the lower part of the nasal septum.

• Vertebral Column: Composed of cervical (7), thoracic (12), lumbar (5), sacral (5), and coccygeal (4) vertebrae. Functions:

  • Support head and trunk.

  • Protect spinal cord.

  • Attachment point for muscles and ribs.

Appendicular Skeleton

Includes bones of upper and lower limbs and girdles attaching them to axial skeleton:

• Pectoral Girdles: Connect upper limbs, composed of:

  • Clavicle: Collarbone; connects the arm to the body.

  • Scapula: Shoulder blade; connects with the humerus and provides muscle attachment.

• Upper Limbs: Include:

  • Humerus: Long bone of the upper arm.

  • Radius: Lateral bone of the forearm, located on the thumb side.

  • Ulna: Medial bone of the forearm, located on the pinky side.

  • Carpals (8): Wrist bones.

  • Metacarpals (5): Bones of the hand.

  • Phalanges (14): Finger bones (3 for each finger, 2 for thumb).

• Pelvic Girdle: Connects lower limbs, formed by:

  • Coxal Bones (2): Each made up of the ilium, ischium, and pubis; supports the weight of the body and protects pelvic organs.

  • Sacrum: Forms back part of the pelvic girdle.

• Lower Limbs: Include:

  • Femur: Thigh bone; longest bone in the body.

  • Patella: Kneecap.

  • Tibia: Medial bone of the lower leg; supports the weight of the body.

  • Fibula: Lateral bone of the lower leg; provides stability.

  • Tarsals (7): Ankle bones.

  • Metatarsals (5): Bones of the foot.

  • Phalanges (14): Toe bones (3 for each toe, 2 for big toe).

Functions primarily in movement and mobility.