Quick viewing(Text Mode)

Skeleton & Joints

Skeleton & Joints

Skeleton & The Skeletal System • Overview of the skeleton • The • The vertebral column and thoracic cage • The pectoral girdle and • The pelvic girdle and lower limb • Adaptations to Bipedalism Overview of the Skeleton

• Regions of the skeleton – axial skeleton = central axis – appendicular skeleton = limbs and girdles

• Number of – 206 in typical adult skeleton Surface Features of Bones Axial and Appendicular Skeleton

• Axial skeleton

• Appendicular skeleton Major Skull Cavities The Skull

• 22 bones joined together by sutures • Cranial bones surround cranial cavity – 8 bones in contact with meninges

• Facial bones support teeth and form nasal cavity and orbit – 14 bones with no direct contact with brain or meninges – attachment of facial and jaw muscles Frontal

• Forms forehead

• Forms roof of the orbit

• Cranial roof and part of its lateral walls

• Temporal lines of temporalis muscle Temporal lines

• Lateral wall and part of floor of cranial cavity – squamous part

– tympanic part

– mastoid part

– petrous portion Petrous Portion of Temporal Bone

• Part of cranial floor

• Houses middle and inner ear cavities

• Rear and base of skull

• Foramen magnum

• Skull rests on atlas

• Body of the sphenoid

• Lesser wing

• Greater wing Maxillary Bones

• Forms upper jaw

• Forms inferomedial wall of orbit

• Forms anterior 2/3’s of hard palate Nasal Bones

• Forms bridge of nose and supports cartilages of nose • Only movable bone

• Holds the lower teeth

• Attachment of muscles of mastication

• Mandibular foramen

• Mental foramen Ramus, Angle and Body of Mandible The Vertebral Column Newborn Spinal Curvature

• Spine exhibits one continuous C- shaped curve Adult Spinal Curvatures

• S-shaped vertebral column with 4 curvatures

• Secondary curvatures develop after birth – Cervical curvature

– Lumbar curvature Abnormal Spinal Curvatures

• Scoliosis

• Kyphosis

• Lordosis Typical Cervical Vertebrae

• Small body and larger vertebral foramen

• Transverse process short with transverse foramen for protection of vertebral

• Bifid or forked spinous process in C2 to C6 Typical Thoracic Vertebrae

• Spinous processes pointed and angled downward

• Rib attachment Lumbar Vertebrae

• Thick, stout body and blunt, squarish spinous process Thoracic Cage

• Attachment site

• Protection

• Involved in respiration True and False Ribs

• True ribs (1 to 7)

• False ribs (8-12)

• 12 pairs of ribs in both sexes Pectoral Girdle

• Attaches upper extremity to the body

• Scapula and clavicle

• Clavicle attaches medially to the sternum and laterally to the scapula

• Scapula articulates with the humerus Clavicle

• S-shaped bone, flattened dorsoventrally Scapula

• Triangular plate overlies ribs 2 to 7 Upper Limb • 30 bones per limb

• Brachium

• Antebrachium

• Carpus

• Manus Brachium and Antebrachium Carpal Bones

• Form

• 2 rows (4 bones each) Metacarpals and Phalanges

• Phalanges are bones of the fingers

• Metacarpals are bones of the palm Sesamoid Bone Pelvic Girdle

• Girdle

• Pelvis

• Supports trunk on the legs and protects viscera Os Coxae (Hip Bone) • Acetabulum is hip socket

• Ilium

• Pubis

• Ischium Comparison of Male and Female

• Female lighter, shallower pubic arch( >100 degrees), and pubic inlet round or oval • Male heavier, upper pelvis nearly vertical, coccyx more vertical, and pelvic inlet heart-shaped Femur and Patella

• Tibia is thick, weight- bearing bone (medial)

• Broad superior head with 2 flat articular surfaces

• Slender lateral strut stabilizes

• Does not bear any body weight

• Joined to tibia by The Ankle and Foot

• Tarsal bones are shaped and arranged differently from carpal bones

• Talus

• Calcaneus

• Distal row of tarsal bones The Foot

• Remaining bones of foot are similar in name and arrangement to the

• Metatarsal I is proximal to the great toe (hallux)

• Phalanges – 2 in great toe – 3 in all other toes Bipedalism and Limb Adaptations Bipedalism and Upright Stance Bipedalism and Head Position The Skeletal System Summary

• Overview of the skeleton • The skull • The vertebral column and thoracic cage • The pectoral girdle and upper limb • The pelvic girdle and lower limb • Adaptations to Bipedalism Joints • Joints Classification – bony – fibrous – cartilaginous • Synovial joints • Types of Movement • of Some Joints – Humeroscapular – – Coxal – Knee • Joint Disease Joints Classification • Arthrology

• Kinesiology Joints Classification

• Classified by freedom of movement – diarthrosis – –

• Classified how adjacent bones are joined – fibrous, cartilaginous, bony or synovial Bony Joint

• Gap between two bones ossifies

• Can occur in either fibrous or Fibrous Joints

• fibers span the space between bones – sutures, gomphoses and syndesmoses -- Sutures

• Immovable fibrous joints

• Serrate - interlocking lines Fibrous Joint -- Sutures

• Lap - overlapping beveled edges

• Plane - straight, nonoverlapping edges Types of Sutures Fibrous Joint -- Gomphoses

• Attachment of a tooth to its socket

• Held in place by fibrous periodontal

• Some movement while chewing Fibrous Joint -- Syndesmosis

• Two bones bound by ligament only

• Most movable of fibrous joints Cartilaginous Joint

• Bones are joined by hyaline cartilage Cartilaginous Joint --

• 2 bones joined by fibrocartilage

• Only slight amount of movement is possible

• Joint in which two bones are separated by a space called a joint cavity General Anatomy

• Articular capsule encloses joint cavity

• = slippery fluid; feeds cartilages General Anatomy

• Articular cartilage = hyaline cartilage covering the joint surfaces

• Articular discs and menisci

• Tendon

• Ligament Tendon Sheaths and Bursae

• Bursa

• Tendon sheaths Components of a Lever • A lever is a rigid object that rotates around a fixed point called a fulcrum

• Rotation occurs when effort overcomes resistance Mechanical Advantage of a Lever

• Two kinds of levers – lever that helps increase output of force

– lever move object further and faster Mechanical Advantage

• Mechanical advantage is calculated from the length of the effort (Muscle moment) divided by the length of the resistance arm (Joint moment) First-Class Lever

• Has fulcrum in the middle between effort and resistance Second-Class Lever

• Resistance between fulcrum and effort Third-Class Lever

• Effort between the resistance and the fulcrum Range of Motion

• Degrees through which a joint can move

• Determined by – structure of the articular surfaces

– strength and tautness of , tendons and capsule

– action of the muscles and tendons Axes of Rotation

• joint has 3 degrees of freedom = multiaxial joint • Other joints – monoaxial or biaxial Types of Synovial Joints Types of Synovial Joints Ball-and-Socket Joints

• Smooth hemispherical head fits within a cuplike depression

• Multiaxial joint Condyloid (ellipsoid) Joints

• Oval convex surface on one bone fits into a similarly shaped depression on the next

• Biaxial joints Saddle Joints

• Each articular surface is shaped like a saddle, concave in one direction and convex in the other

• Biaxial joint Gliding Joints

• Flat articular surfaces in which bones slide over each other

• Limited monoaxial joint Hinge Joints

• One bone with convex surface that fits into a concave depression on other bone

• Monoaxial joint Pivot Joints

• One bone has a projection that fits into a ringlike ligament of another

• First bone rotates on its longitudinal axis relative to the other Types of Movement Flexion, Extension and Hyperextension

• Flexion

• Extension

• Hyperextension Flexion, Extension and Hyperextension Abduction and Adduction

• Abduction – Hyperabduction

• Adduction Elevation and Depression

• Elevation

• Depression Protraction and Retraction

• Protraction

• Retraction Circumduction Rotation • Medial rotation

• Lateral rotation Supination and Pronation • In the and foot

• Supination

• Pronation Movements of Head and Trunk

• Flexion, hyperextension and lateral flexion of vertebral column Rotation of Trunk and Head

• Right rotation of trunk; rotation of head Movements of Mandible

• Lateral excursion • Medial excursion • Protraction Movement of Hand and Digits

• Radial and ulnar flexion • Abduction of fingers and thumb • Opposition is movement of the thumb to approach or touch the fingertips • Reposition is movement back to the anatomical position Movements of the Foot

• Dorsiflexion is raising of the toes as when you swing the foot forward to take a step (heel strike) • Plantarflexion is extension of the foot so that the toes point downward as in standing on tiptoe • Inversion is a movement in which the soles are turned medially • Eversion is a turning of the soles to face laterally The Humeroscapular Joint • Most freely movable joint in the body – shallowness and looseness

• Supported by ligaments and tendons – 3 glenohumeral, coracohumeral, transverse humeral and biceps tendon The Humeroscapular Joint • Supported by rotator cuff musculature

• 4 Bursae associated with shoulder joint Stabilizers of the Shoulder Joint Tendons of Rotator Cuff Muscles Dissection of Shoulder Joint Elbow Joint The Elbow Joint • Single enclosing the humeroulnar and humeroradial joints Elbow Joint Hip Joint The Coaxal (hip) Joint

• Head of femur articulates with acetabulum Hip Joint Dissection of Hip Joint Knee Joint The Knee Joint • Most complex diarthrosis – Patellofemoral

– Tibiofemoral The Knee Joint • Joint capsule anteriorly consists of patella and extensions of quadriceps femoris tendon Knee Joint – Sagittal Section Knee Joint – Anterior and Posterior Views

• Anterior and lateral cruciate ligaments

• Medial and lateral collateral ligaments Knee Joint – Superior View

• Medial and lateral absorb shock and shape joint Dissection of Knee Joint Joint Disease Arthritis

• Arthritis is a broad term for pain and inflammation Arthritis

• Osteoarthritis results from years of joint wear Arthritis

• Rheumatoid arthritis is autoimmune attack on joint Rheumatoid Arthritis Summary • Joints Classification – bony – fibrous – cartilaginous • Synovial joints • Anatomy of Some Joints – Humeroscapular – Elbow – Coxal – Knee • Joint Disease

Top View