RAD125 Anatomy Humerus & Forearm PDF

The Humerus and Forearm Anatomy, Physiology & Pathology RAD125 Kim Martin [email protected] With thanks to: Dr Laura McLaughlin Upper limb From the shoulder to the fingers Consists of 30 Bones Humerus, ulna, radius (n=3) Carpal bones (n=8) Metacarpal (n=5)...

The Humerus and Forearm Anatomy, Physiology & Pathology RAD125 Kim Martin [email protected] With thanks to: Dr Laura McLaughlin Upper limb From the shoulder to the fingers Consists of 30 Bones Humerus, ulna, radius (n=3) Carpal bones (n=8) Metacarpal (n=5) Phalanges (n=14) Overview Terminology Bones Articulations Tendons/muscles Blood supply Nerve supply Pathology Learning Outcomes After listening to this lecture, you should be more aware of: The position of the radius, ulna and humerus in relation to the appendicular skeleton How to describe the anatomy of the radius, ulna and humerus How to outline normal and abnormal variants How to describe normal and abnormal pathology and relate it to the mechanism of injury. Terminology recap Palm facing down Lateral/radial Medial/ulnar Proximal Distal Supination Pronation Palm facing up Describing a bone Type/classification of bone e.g. long bone Position Articulations Main parts Surface markings/features of the main parts Ossification Additional points specific to the particular bone Know the diagrams Forearm Two long bones Radius – lateral 1. Scaphoid Ulna - medial 2. Lunate 3. Styloid process of radius 4. Styloid process of ulna 5. Head of ulna 6. Radius 7. Ulna 8. Tuberosity of radius 9. Neck of radius 10. Head of radius 11. Proximal radioulnar joint Radius Main parts – proximal Head – rounded with concave superior surface Neck – annular ligament Radial tuberosity – biceps brachii muscle Radius Shaft Anterior border Posterior border Interosseous border – interosseous membrane forms middle radio-ulnar joint Anterior surface – nutrient foramen Posterior surface Lateral surface  Radius Main parts – distal Ulnar notch – medial aspect, forms distal radio-ulnar joint Radial styloid process Distal surface – articulation with carpal bones Radius Articulations Head of radius Radial notch of ulna -proximal radio- ulnar joint Capitulum of humerus Distal radius Head of ulna to form distal radio- ulnar joint Scaphoid and lunate – wrist joint Ulna  Main parts – proximal ◦ Olecranon process – triceps tendon ◦ Coronoid process – anterior ◦ Ulnar tuberosity – anterior surface of coronoid – brachialis muscle ◦ Troclear notch – articulates with trochlea of humerus ◦ Radial notch – lateral aspect of coronoid process – articulates with head of radius Ulna Shaft Anterior border Posterior border Interosseous border – lateral aspect Anterior surface – nutrient foramen Medial surface Posterior surface Ulna Main parts – distal Head Ulnar styloid process Ulna Articulations Radial notch ulna – head of radius – proximal radio-ulnar joint Trochlear notch of ulna – trochlea of humerus Head of ulna – ulnar notch of radius – distal radio-ulnar joint Head of ulna – articular disc – no direct articulation with carpal bones Forearm Muscles Extrinsic muscles of the hand Trauma Galeazzi’s Fracture Fracture mid to distal one third radius Dislocation of distal radio-ulnar joint Trauma Monteggia’s Fracture Mechanism of injury – direct blow, hyperpronation injury Dislocation of radial head with fracture of proximal one third of ulna Trauma Find out more: Night stick fracture Chauffeur’s fracture Triangular fibro-cartilage injuries Distal radio-ulnar joint instability Greenstick fracture  The Humerus Longest and largest bone ↑ limb  Lateral AP Case courtesy of Weiling Tan, Radiopaedia.org, rID: 166765 The Proximal Humerus Proximal end has a rounded head which articulates with the glenoid cavity of scapula (glenohumeral joint) Distal to head is anatomical neck Greater tubercle is a lateral projection distal to anatomical neck Lesser tubercle projects anteriorly Intertubercular sulcus runs between tubercles Surgical neck lies distal to tubercles (common # site) The Proximal Humerus The Humerus: Shaft Cylindrical at proximal end Flattened and broad at distal end Lateral middle portion has V shaped deltoid tuberosity (attachment for tendons of deltoid muscle) The Distal Humerus Articulations Capitulum- rounded knob on lateral aspect articulates with HOR Radial fossa (ant) receives HOR when forearm flexed Trochlea – medial to capitulum, spool shaped surface articulates with ulna Coronoid fossa anterior depression receives coronoid process of ulna when forearm flexed Olecranon fossa – posterior depression receives olecranon of ulna when forearm straightened Medial and lateral epicondyles allow for tendons to attach The Humerus - Ossification Primary centre: shaft 8th week IU life Secondary centre: upper end-3 centres Head @ 6 months Greater tuberosity @1-2 yrs Lesser tuberosity @ 4-5 yrs Fuse @ 6 yrs Fuse with shaft 18-20 yrs Lower end capitulum @ 1 yr Medial epicondyle @ 4-6 yrs Trochlea @ 9-10 yrs Lateral epicondyle @12 yrs 3 fuse at puberty Fuse with shaft @14-16yrs Medial epicondyle fuses with shaft @ 20yrs The Humerus A lesser tuberosity Anterior B greater tuberosity C Intertubercular sulcus D deltoid tuberosity E lateral border F lateral supracondylar ridge G lateral epicondyle H radial fossa I capitulum J Trochlea K medial epicondyle L coronoid fossa M medial surpracondylar ridge N surgical neck O Anatomical neck P Head of humerus (HOH) The Humerus 1 HOH Posterior 2 anatomical neck 3 surgical neck 4medial border 5 medial surpracondylar ridge 6 Olecranon fossa 7 medial epicondyle 8 groove for ulnar nerve 9 trochlea 10 lateral epicondyle 11 lateral supracondyler ridge 12 spiral groove 13 greater tuberosity Nerve Supply Nerve Supply Nerve Supply Surgery Surgery Osteosarcoma Case courtesy of Karim Hussein, Radiopaedia.org, rID: 56021 Metastasis Case courtesy of Andrew Dixon, Radiopaedia.org, rID: 72791 References Gunn C. 2018. Bones and joints. 7th Ed. Philadelphia: Elsevier Ltd. http://www.szote.u-szeged.hu/Radiology/Anatomy/skeleton/elbow1.htm http://www.szote.u-szeged.hu/Radiology/Anatomy/skeleton/elbow2.htm Frank E. D., Long B. W., Smith B. J. (2007). Merrill’s Atlas of Radiographic Positioning Procedures, Volume 1. Eleventh Edition. Missouri: Mosby Elsevier. Wheeless Textbook of Orthopaedics http://www.wheelessonline.com/ortho/trauma_fractures_index Frank E. D., Long B. W., Smith B. J. (2007). Merrill’s Atlas of Radiographic Positioning Procedures, Volume 1. Eleventh Edition. Missouri: Mosby Elsevier. Learning Radiology http://www.learningradiology.com/ Tortora and Grabowski. Principles of anatomy and physiology. 11th ed. Weir and Abraham : Imaging atlas of human anatomy. 2006. Further resources http://uwmsk.org/RadAnat/Hand.html Self-Tests Self-Tests Self-Tests