Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Download appendicular skeleton
Document related concepts
Transcript
APPENDICULAR SKELETON • The appendicular skeleton is organized into girdles and limbs – Girdles • Pectoral • Pelvic – Limbs • Upper • Lower Girdles • Girdle – Belt, zone, encircling structure • Girdles attach bones of the upper and lower limbs to the axial skeleton Shared Limb Characteristics • Note that both upper and lower limbs share basic structural and functional characteristics – Proximal anchoring to axial skeleton – Distal elaboration for contact with environment Clinical • The appendicular skeleton is critical in mobility and manipulation • Disorders of the appendicular skeleton are generally more common and disabling than those of the axial skeleton – Hand PECTORAL GIRDLE AND UPPER LIMB Pectoral Girdle Background • The pectoral girdle is an incomplete ring consisting of four bones – Two clavicles – Two scapulae • The “ring” is completed anteriorly by the manubrium – Posterior “gap” allows mobility – scapuli have to move Cavical Structure • The clavicle (collar bone) has the general appearance of an italic letter – The curvatures increase the resilience of the clavicles • The clavicle is palpable along its entire length Fracture • The clavicle is a moveable crane-like strut, which transmits shock from the upper limb to the axial skeleton – absorbs force from arms • As such, it is one of the most frequently fractured bones • In a fracture of the clavicle the distal end generally drops (due to weight of limb) while the proximal end rises Scapula Location • The scapula (shoulder blade) is a triangular-shaped bone on the posterolateral aspect of the thorax • It overlies ribs 2-7 Structure/Function • There are two principal structural/functional requirements of the scapulae • Things look the way they do b/c of what they do 1. Liberal amount of movement (gliding along the back of the ribs) • Smooth anterior surface 2. Ability to be acted upon by many muscles • Presence of several crests, angles, and protrusions- accomidate muscle attachment Superior angle Spine Lateral angle Acromion Subscapular fossa Inferior angle Supraspinous fossa Suprascapular notch Neck Coracoid process Glenoid fossa Infraspinous fossa Coracoid process Acromial angle Acromion Spine Medial border Inferior angle Upper Limb Background • The humerus is the bone of the arm • It is a classic long bone with distinct features at either end – Proximal end • Part spheroid, and part platform – Distal end • Flat, specialized for strong hinge-like articulation Anatomical neck vs surgical neck (where you are more likely to see a break) Condyle: the articular surface of a long bone Trochlea – pulley Capitulum – head Olecranon fossa – articulates with the ulna (olecranon) Greater tubercle Greater tubercle Lesser tubercle ateral picondyle Medial epicondyle Medial epicondyle Forearm Background • The forearm is formed by two parallel bones, the ulna and the radius – Ability to rotate hand with flexed elbow Ulna • The ulna is the longer, medial, stabilizing bone of the forearm • The large, proximal end of the ulna is specialized to articulate with the humerus • The distal end does not reach the wrist – No articulation Lateral epicondyle Radius • • The laterally-positioned radius is a more robust cylinder than the ulna – Application of force – actually stronger It has opposite emphases compared to the ulna – Allows for versatility of hand The styloid process of the radius should be inferior/distal to the styloid process of the ulna ANTERIOR VIEW POSTERIOR VIEW Olecranon Head of radius Posterior border of ulna Hand Background • The bones of the hand are classified into three regions 1. Carpus 2. Metacarpus 3. Phalanges Carpus • The wrist, or carpus, consists of eight carpal bones arranged in two rows of four • The scaphoid and the lunate are in contact with the radius – Note location of scaphoid Anatomical Snuff Box • The anatomical snuff box is the triangular depression on the posterolateral side of the wrist • Certain structures of clinical importance are located in the box – Radial artery • Pulse can be taken – Scaphoid bone and radial styloid process • Palpation for fracture Metacarpus • The metacarpus is composed of five metacarpal bones • The metacarpus forms the skeleton of the palm of the hand • The thumb is the first metacarpal Phalanges • Each digit has three phalanges – Thumb has only two • The size of the phalanges decreases from proximal to distal • The tips of the distal phalanges are flattened and expanded – Accommodate nails So long top part here comes the thumb PELVIC GIRDLE AND LOWER LIMB Pelvic Girdle Background • The pelvic girdle has protective and supportive functions for the abdomen, pelvis, and the lower limbs – Core of the core? Bony Structure • The pelvic girdle is formed by three bones – Right and left hip bones • These are also known coxal bones, os coxae, pelvic bones, or hip bones – Sacrum Hip Bones Background • Each hip bone arises from the fusion of three bones after puberty 1. Ilium 2. Ischium 3. Pubis • Note that all three bones contribute to the acetabulum – where head of femur articulates Ilium • The illium has two general parts 1. Thick, weight-bearing medial portion 2. Thin, wing-like portion (ala) • Multiple surface features for muscular attachment Ischium • The ischium forms the posteroinferior part of the hip bone • Ischial tuberosity – What you sit on – Attachment of hamstrings Pubis • The pubis forms the anteromedial part of the hip bone • The bodies of the pubis articulate at the pubic symphysis • The rami project laterally – Site of attachment of penis and clitoris Iliac crest (tuberosity) Pubic symphysis Anterior superior iliac spine Pubic tubercle Posterior superior iliac spine Supracristal plane high points of iliac crests - level of L4/L5 IV disc Ischial tuberosity Your dimples show location of PSIS -(level S2) Lower Limb Thigh Background • The femur is the bone of the thigh – It is the longest and heaviest in the body • It is identical in concept to the humerus, but with more exaggerated ends – Trochanters vs. tubercles – Two large condyles vs. smaller single condyle Patella • The patella—a sesamoid bone—is embedded in the quadriceps tendon – Sesamoid bones grow in tendons • The patella serves to increase leverage in the extending knee – Lengthens lever arm Leg Background • Like the forearm, the anatomical leg features two bones – Tibia and fibula • In the leg, mobility is sacrificed for weight-bearing stability – Tibia is 2nd biggest bone • Both tibia and fibula contribute to the ankle – Malleoli Tibia • The tibia is dominant both proximally and distally – Compare to forearm • It has a triangular shape in cross-section – Medial surface represents the “shin” • Proximally, the medial and lateral condyles form a tibial plateau Fibula • The fibula is positioned posterolaterally to the tibia • It has no weight-bearing function nor does it articulate with the femur – Role in ankle stability • It provides multiple points of muscle attachment Fibula – ulna Tibia – radius Foot Background • The bones of the foot may be classified in two different ways 1. Anatomically 2. Functionally Anatomical Classification • In this classification the bones of the foot are organized by form 1. Phalanges – like a miltary phalanx – all lined up in a row! 2. Metatarsus 3. Tarsus Functional Classification • In this classification the bones of the foot are organized by functional regions 1. Forefoot 2. Midfoot 3. Hindfoot Tarsus • There are seven tarsal bones organized into proximal and distal rows • Only the talus articulates with the leg bones – Receives the weight of the body via the tibia • The term tarsus is synonymous with ankle, however, the ankle is generally considered to include the malleoli • Talus – aticulates with the Tib-fib • Cuneiforms – medial – intermedial – lateral Metatarsus and Phalanges • • • The metatarsals are numbered 1-5 starting on the medial side Metatarsal 1 is the shortest and thickest Each digit has three phalanges – Hallux has only two Toe flexion/extension Anatomical division Foot eversion/inversion Calcaneal tuberosity Greater trochanter Patella Medial epicondyle Lateral epicondyle Lateral epicondyle Gerdy tubercle Head of fibula Tibial tuberosity Tibial tuberosity Anterior border of tibia Lateral malleolus Medial malleolus Lateral malleolus
