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Unformatted text preview: www.brain101.info 1 THE UPPER EXTREMITY Pectoral and Scapular Regions The Arm The Extensor Forearm The Flexor Forearm Joints of the Upper Extremity The Hand Fractures and Entrapment Neuropathies MOTOR UNIT: A motor (GSE) neuron, plus all of the muscles that neuron innervates. Fine Motor Control: Lots of motor neurons going to relatively few muscles. Gross Motor Control: A few motor neurons going to lots of muscles. PECTORAL AND SCAPULAR REGIONS THE SCAPULA: Supraspinatus Fossa: Depression in the scapula, above the scapular spine. Infraspinatus Fossa: Depression in the scapula, below the scapular spine. TRAPEZIUS MUSCLE: It is innervated by the spinal accessory nerve. Hence with a cervical neck fracture, some people can still shrug their shoulders, even though they've lost upper-limb innervation, due to residual innervation from this nerve. TRIANGLE OF AUSCULTATION (N399a): On the medial back, it is an area of little muscle and hence a good place to listen to the lungs. Medial Border: Trapezius muscle Lateral Border: Teres Major, laterally and deep. Inferior Border (base): Latissimus Dorsi QUADRANGULAR SPACE (N401b): Just medial to the surgical neck of the humerus on the posterior side. Superior border: Teres Minor (posteriorly) Inferior border: Teres Major (anteriorly) Lateral border: Lateral head of the Triceps Medial border: Long head of the Triceps CONTENTS: These guys can be damaged with a fracture of the neck of the humerus. o Axillary Nerve o Posterior Circumflex Humeral Artery TRIANGULAR SPACE (N401a, N401b): Anterior aspect, medial to the neck of the humerus. Lateral border: Long head of the triceps. Upper border: Teres Minor Lower border: Teres Major CONTENTS: Circumflex Scapular Branch of the subscapular artery. www.brain101.info 2 TRIANGULAR INTERVAL (N401b): Between the two heads of the triceps muscle, inferior to the teres major. CONTENTS: Deep Brachial Artery and Radial Nerve , both of which continue along the radial groove of the humerus. SCAPULA : The shoulder blade. From top to bottom, order of the Scapular Muscles (N401): o Supraspinatus o Infraspinatus o Teres Minor o Teres Major WINGED SCAPULA : Both the Serratus Anterior and Rhomboids insert on the medial aspect of the scapula. If you lose this insertion, you can get winged scapula, where the scapula does not stay in place and is raised a bit from the posterior wall. Deltoid Muscle: It inserts on the Deltoid Tuberosity of the humerus and has multiple actions Anterior part flexes and medially rotates the arm. Posterior part extends and laterally rotates the arm. Lateral fibers abduct the arm....
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This note was uploaded on 01/30/2011 for the course BIO 210 taught by Professor S during the Spring '10 term at University of Toronto- Toronto.
- Spring '10