Fracture in the arm-1

Fracture in the arm-1

1. bone

   • Anatomy Arm Bone
   • bone structure
   • ossification
     • Intrmembranous
     • Endochondral
   • Types of Bone Cells
     • Have receptors for the parathyroid hormone and found where active bone is being formed. “ osteoblasts”
     • Present where bony resorption is required. “osteoclasts”
     • Play a role in deposition of calcium. “Osteocytes”
     • In low O2 tension they may change into chondrogenic cells. “Osteoprogenitor cells”

2. Muscles of the arm

   • Anterior Compartment
     • Biceps Brachii
       • Action : Both heads Supination of the flexed forearm Flexion of the elbow joint - The short head is a weak flexor of the shoulder joint- The long head prevents the upward dislocation of the shoulder joint Nerve supply : Musculocutaneous nerve .
     • Coracobrachialis
       • Action : Flexion and adduction of the arm . Nerve supply : Musculocutaneous Nerve
     • Brachilis
       • Action : Flexion of the elbow Nerve supply : Musculocutaneous nerve Radial nerve supplies a small lateral part
   • posterior Compartment
     • Triceps Brachii
       • Action : Powerful extensor of the elbow joint Its main function is to keep the elbow extended when one is pushing an object Nerve supply : Each head receives a separate branch from the radial nerve

3. muscles of the back

   • superficial layer
     • Trapezius
       • Action : Elevates the arm with levator scapulae Rotates the scapula superiorly with serratus anterior Retracts scapula with rhomboids Nerve supply : Motor : spinal accessory (XI)
     • Latissmus Dorsi
       • Action : Adducts , extends and rotates the arm medially Pulls trunk upwards when arm is above the head ( climbing muscle ) Nerve supply : Thoracodorsal nerve ( C7 , 8 )
     • Levator scapular
       • Action : Elevates the scapula Nerve supply : Dorsal scapular nerve (C5)
     • Rhomboideus
       • Action : Retracts , elevates and rotates the scapula inferiorly Nerve supply : Dorsal scapular nerve C5

4. Arteries of Arm

   • Axillary artery
     • continuation of subclavian.a, b/w outer border of 1st rib and lower border of teres major, crossed by p.minor and divided into 3 parts.
   • Brachial artery

5. Fractures

   • A break in the structural continuity of the bone tissue.
   • Mechanism
     • -By a single traumatic event -Repetitive stress in a short period of time (stress fracture) - Abnormal weakening of the bone (Osteoporosis, pathological fracture).
   • Clinical Picture
     • Pain Loss of function Deformity Swelling Hematoma Echymosis wound
   • Types Of Fractures
     • Open Fractures : When the bony fragments are exposed to external environment by means of a wound (through a skin wound)
     • Closed Fractures : The fracture fragments are not exposed to outside

6. nerve

   • ANTERIOR INNERVATION OF NERVES TO ARMS.
     • radial
       • Arises from brachial plexus in root of neck and under the cervix to behind the humerus forming circumflex BY PASSING THROUGH THE LOWER TRIANGULAR SPACE and then goes anteriorly into the lateral side of brachialis muscle (origin: arise from lower anterior half of humerus insertion: ulna tuberosity) and then continous into the forearms as superficial radial nerve to supply foramrs muscles like brachioradialis muscle and more…
       • Injury to the radial nerve
         • Wrist & Finger Drop (Crutch Palsy)
     • Axillary
       • PASSES INFRONT THE SUBSCAPULAR MUSCLE, TO THE QUADRITRIANGULAR SPACE INTO THE POSTERIOR SIDE OF HUMERUS WHERE IS MEETS IT COMPANION POSTERIOR CIRCUMFLEX HUMAERAL ARTERY AND SURROUNDS SURGICAL NECK OF HUMERUS. SO ANY FRACUTRE WILL NOT ONLY LEAD TO HEMORRHAGE BUT ALSO TO DAMAGE TO THIS NERVE THEREFORE DAMAGE TO DELTOID AND TERES MINOR MOVEMENTS. WHILE THE RADIAL NERVE WILL MOVE BACKWORD THROUGH THE LOWER  quadrangular SPACE.
     • MUSCLULOCUTANOUS
     • MEDIAN
       • IT IS ANTERIOR TO THE MEDIAL EPICONDYL OR IT SITS ON THE CORONOID FOSSA WHILE THE ULNER NERVE IS POSTERIOR TO MEDIAL EPICONDYL OR POSTRIOR TO CORONOID FOSSA. (IT WILL ENETR CORONOID FOSSA MOST MEDIALLY)
     • ULNAR
       • VERY DANGEROUS SITE CUZ ITS EXACTLY IN THE ELBOW JOINT. SO IF U HAD ANY FRATURE OF DISLOCATION OF ELBOW JOINT THEN U ULNAR NERVE IS MOST PRONE TO ANY SORT OF DAMAGE LIKE HEMORRHAGE.
   • nerve injury
     • Types of Nerve injury
       • NEURAPRAXIA
         • the axon remains intact, but there is myelin damage causing an interruption in conduction of the impulse down the nerve fiber.
         • Chronic mechanical pressure
       • AXONOTMESIS
         • Seen in closed fractures and dislocations Axonotmesis is the disruption of axons and myelin
         • The axons degenerate proximally and distally from the area of injury . Distal degeneration is known as Wallerian degeneration
       • NEUROTMESIS
         • Division of the nerve trunk Occurs in open wounds
         • A Neuroma is formed (regenerating fibers + Schwann cells + fibroblasts)
     • Management of Peripheral Nerve Injury
       • -Surgical exploration of the nerve may be undertaken if no functional improvement occurs over 3 months - In the absence of conduction, the injured segment should be resected and end-to-end primary anastomosis attempted.

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