GA1 Study Tips - Forelimb Anatomy (Summer 2024)

ALYSSA PELLIN HOW TO VET SCHOOL STUDY TIPS FOR ANATOMY AND VET SCHOOL IN GENERAL Summer 2024 GA1 Tutoring DIRECTIONAL TERMINOLOGY TUTOR: ALYSSA PELLIN Week 1 Regions Cervical = neck Thoracic = chest Lumbar = lower back Brachial = arm Antebrachial = forearm Cubital = elbow Carpal = “wrist” INTER CE R...

ALYSSA PELLIN HOW TO VET SCHOOL STUDY TIPS FOR ANATOMY AND VET SCHOOL IN GENERAL Summer 2024 GA1 Tutoring DIRECTIONAL TERMINOLOGY TUTOR: ALYSSA PELLIN Week 1 Regions Cervical = neck Thoracic = chest Lumbar = lower back Brachial = arm Antebrachial = forearm Cubital = elbow Carpal = “wrist” INTER CE RV IC BAR LUM AL THORACIC AC HI AL Prefixes “extra” - outside of “intra” - within/inside of “inter” - between “trans” - across INTRA TRANS CUBITAL BR terminology EXTRA ANTE-BRACHIAL CARPAL terminology Planes Transverse Divides cranial from caudal Like sliced bread Median/Sagittal Divides left from right Median = equal halves Sagittal = uneven halves Dorsal Divides dorsal from ventral terminology Directions Ventral vs dorsal Plantar/palmar Cranial vs caudal Rostral Lateral vs medial Axial vs abaxial Proximal vs distal CRANIAL ROSTRAL DORSAL ABAXIAL MEDIAL IAL MED VENTRAL PLANTAR LATERAL PALMAR AXIAL CAUDAL Recumbencies Right lateral recumbency Dorsal recumbency Ventral recumbency Left lateral recumbency GA1 Tutoring SMALL ANIMAL FORELIMB TUTOR: ALYSSA PELLIN INTROduction General Information 60% of the weight is carried in the forelimbs 2 muscles hold up the trunk/body on the forelimbs: Pectoral mm. Serratus ventralis m. Active Terminology Flexion of a joint = angle decreases Extension of a joint = angle increases Pronation: “pour out the soup” Medial rotation Supination: “bowl of soup” Lateral rotation ABduction ADDuction: “adding” Note Synergistic muscles: work together, to achieve the same action on the joint (on the same side of the joint) Antagonistic muscles: have opposite effects on the joint when they contract (on opposite sides of the joint) Shoulder Flexion Shoulder Extension INTROduction Wolf’s Law: bone in a healthy animal will adapt to the loads under which it is placed. Osteology Function of bones Protects internal organs Structural support of the body Storage of minerals (Ca2+ and P) and fat Hematopoiesis Works with muscles and joints to permit movement Types of Bones Flat bones (ex: Scapula) Long bones (ex: humerus) Diaphysis - contains a medullary cavity Epiphysis Physis (growth plate) at least 3 of these in each long bone Only present in young animals Short bones (ex: carpal bones) Sesamoids: found within tendons Irregular bones (ex: vertebrae) Joint flexion Joint extension Lateral view Scapula Scapula Medial view Humerus Radius Ulna Coracoid process Acromion Humerus cranial view caudal view Scapula Humerus Radius Ulna ulna & Radius MANUS Carpal bones Proximal carpals Intermedioradial carpal Ulnar carpal Accessory carpal Distal carpals (1-4) note: Carpal 4 articulates with MC4 and MC5 Metacarpals (1-5) MC1 = Pollux = dewclaw Phalanges Proximal phalanges (1-5) Middle phalanges (2-5) NOT present in the dewclaw Distal phalanges (1-5) Sesamoids Very small bones, embedded within tendons/muscles Alleviates tension Ulnar carpal bone Intermedioradial carpal bone Accessory carpal bone Proximal carpals Distal carpals MC1 Proximal phalanx 1 Metacarpals Distal phalanx 1 Sesamoids Proximal phalanges Accessory Carpal Middle phalanges Distal phalanges Joints Type of Joint Connection Amount of Movement Example Fibrous joint Strong connective tissue Limited to NONE Skull Cartilaginous joint Cartilage Limited Intervertebral discs Synovial joint Joint cavity FULL movement Shoulder Accessory Synovial Structures Ligaments - bands of connective tissue Can be intra/extra-capsular Note: different from a tendon (origin and insertion of a muscle) Menisci - fibrocartilage located within synovial cavities Allows for the bones to fit together better Synovial Joint Anatomy Layers of the articular capsule Synovial membrane: highly vascular, innervated Produces synovial fluid Fibrous layer: structural support Joint cavity - contains synovial fluid Lubrication and nutrition of articular cartilage # of Articulating Bones Simple - joint between 2 bones Compond jointbetween 3+ bones Fit Congruent - fit well Incongruent - don’t fit well Probably has menisci joint types - SHAPE (A) Plane joint (C) Pivot joint (E) Ellipsoidal joint ex: canine carpus. (B) Hinge joint (D) Condylar joint (F) Saddle joint ex: canine DIP joint (G) Spheroidal joint (aka ball and socket) ex: canine hip joint Other synovial Structures Bursa Fluid-filled pouch, protects a tendon as it passes over bone Tendon Sheath Fluid-filled sleeve, facilitates gliding between a retinaculum and bone forelimb joints Shoulder = “Glenohumeral” joint Type: ball and socket Direction of movement: all Elbow = “humeroradioulnar” or “cubital” joint Type: hinge Direction of movement: flexion/extension Very stable, due to collateral ligaments Carpal joints Antebrachiocarpal (aka radiocarpal) Greatest range of motion Separate synovial cavity Middle carpal + Carpometacarpal their synovial cavities communicate Manus --> only allow flexion/extension Metacarpophalangeal Proximal Interphalangeal (PIP) Distal Interphalangael (DIP) note: except the thumb/pollux --> only 1 interphalangeal joint Glenohumeral Joint Humeroradioulnar joint Metacarpophalangeal joint PIP DIP Other important structures Structure What it holds down Location Palmar Annular Ligament Flexor manica (SDF) Tendon of DDF MCP joint PDAL Tendon of SDF and DDF mid-Proximal Phalanges DDAL Tendon of DDF Middle phalanx Palmar Carpal Ligament On the palmar surface of the Carpal joints Palmar Annular Ligament Carpal Canal Borders Dorsal border: Palmar carpal ligament Lateral border: Accessory carpal bone Palmar border: Flexor retinaculum Proximal Digital Annular Ligament Flexor Retinaculum Function: prevents bowing of tendons during contraction Distal Digital Annular Ligament EXTRinsic muscles Definition: originate from head/neck/trunk, insert on the forelimb Concepts If the limb is weight-bearing, the body will move around the limb with muscle contraction If the limb is not weight-bearing, the limb will move with muscle contraction Aponeurosis: flat sheet-like tendon, allows for a broader muscle attachment INTRinsic muscles Definition: both originate AND insert on the forelimb Concepts Muscles on the same side of a joint will exert the same function on that joint A muscle must cross a joint in order to act on that joint Serratus ventralis Superficial pectoral muscles Descending part Transverse part Deep pectoral muscle Pectorals **sling muscle** **sling muscle** Shoulder Extensor Superficial, descending Superficial, transverse Deep Brachiocephalicus Mastoid part Not important for now Clavicular intersection divides it into: Cleidobrachialis Cleidocephalicus cervical part mastoid part Note: “cleido” prefix indicates clavicle EXTRinsic muscles Shoulder Extensor Cervical part Latissimus dorsi Cleidocephalicus Clavicular intersection Cleidobrachialis Shoulder Flexor Deep pectoral Traps rhomboids Rhomboideus cervicis Rhomboideus cervicis Rhomboideus capitis Thoracic trapezius Cervical trapezius Rhomboideus capitis Rhomboideus thoracis Rhomboideus thoracis Omotransversarius EXTRinsic muscles