Chapter 6: KNES 217 Anatomy - FALL 2022 PDF

KNES 217 Objectives: Identify on a chart or human selected musculoskeletal features List the planes and axes of motion of the motions around the elbow and radioulnar joints Organize and list the muscles that produce primary movements of the elbow and radioulnar joints  Most upper extremity mo...

KNES 217 Objectives: Identify on a chart or human selected musculoskeletal features List the planes and axes of motion of the motions around the elbow and radioulnar joints Organize and list the muscles that produce primary movements of the elbow and radioulnar joints  Most upper extremity movements involve the elbow & radioulnar joints  Usually grouped together due to close anatomical relationship  Elbow joint movements may be clearly distinguished from those of the radioulnar joints  Radioulnar joint movements may be distinguished from those of the wrist  Ulna is much larger proximally than radius  Radius is much larger distally than ulna  Scapula & humerus serve as proximal attachments for muscles that flex & extend the elbow  Ulna & radius serve as distal attachments for the same muscles  Distal end of medial humerus – medial epicondyle and trochlea Distal end of lateral humerus – lateral epicondyle and capitulum Ulna: -Coronoid process -Ulnar tuberosity (brachialis) Radius: -Head -Radial tuberosity (biceps) Anterior view  Ulna: -Trochlear Notch (concave notch that articulates with trochlea of humerus) Ulna: -Olecranon process (large proximal tip of ulna – makes it the “point” or “tip”) Medial view  Humerus: -Lateral epicondyle less prominent than medial epicondyle -Olecranon fossa – accepts the olecranon process of ulna Radius: -Radial head (disc-like structure) Lateral view -Radial head articulates with radial notch of ulna (proximal radioulnar joint) 4 Joints make up the elbow and forearm complex  Elbow: ▪ Humeroulnar ▪ Humeroradial  Forearm: ▪ Proximal radioulnar ▪ Distal radioulnar  Elbow motions (General)  Primarily involve movement between articular surfaces of humerus & ulna ▪ Specifically, humeral trochlea fitting into ulna trochlear notch  Radial head has a relatively small amount of contact with capitulum of humerus  As elbow reaches full extension, olecranon process is received by olecranon fossa ▪ Increased joint stability when fully extended  Humeroulnar Articulation:  Articulation between concave trochlear notch (ulna) around the convex trochlea of the humerus  Hinge joint (1 degree of freedom) ▪ Flexion and extension  Carrying Angle:  Angle formed by the long axis of the humerus and ulna ▪ Normal carrying angle ▪ 10-15 degrees in women ▪ 5-10 degrees in men  Cubitus valgus ▪ Increased carrying angle ▪ Baseball pitchers  Adaptation to repeated valgus loading during throwing  Cubitus varus ▪ Decreased carrying angle   Humeroradial Joint:  Articulation between cuplike fovea of radial head and capitulum of humerus ▪ Pivot joint ▪ Flexion ▪ Extension Key: Little contact between radius and humerus  As elbow flexes 20 degrees or more, its bony stability is unlocked, allowing for more side-to-side laxity  Stability in flexion is more dependent on the radial collateral ligament (lateral) & the ulnar collateral ligament (medial)  Ulnar collateral ligament is critical in providing medial support to prevent elbow from abducting when stressed in physical activity  Many contact sports & throwing activities place stress on medial aspect of joint, resulting in injury  particularly crucial to high-velocity sporting activities requiring optimal medial elbow stability like baseball pitching  Injury often requires surgery ▪ “Tommy John procedure”: UCL surgical reconstruction using a tendon graft, such as palmaris longus tendon 6-15 2012 ESPN the Magazine: 14,232 regular season days MLB pitchers recovering from Tommy John Surgery have spent on the DL in past 5 years. $193,503,317 spent on their salaries.  A P T  Radial collateral ligament provides lateral stability & is rarely injured  Annular ligament provides a sling effect around radial head for stability  Keeps it in contact with radial notch of ulna  Elbow ROM  Flexion and extension Normal ROM: 0 degrees of extension to 145-150º of flexion  Radioulnar joint  Pivot-type joint  Radial head rotates around at proximal ulna (radial notch)  Annular ligament maintains radial head in its joint 6-21  Radioulnar joint  Supinate 80 to 90 degrees from neutral  Pronate 70 to 90 degrees from neutral  Radioulnar joint  Joint between shafts of radius & ulna held tightly together between proximal & distal articulations by an interosseus membrane (syndesmosis) ▪ Substantial rotary motion between the bones  Flexion  movement of forearm to shoulder by bending the elbow to decrease its angle  Extension  movement of forearm away from shoulder by straightening the elbow to increase its angle  Pronation  internal rotary movement of radius on ulna that results in hand moving from palm-up to palm- down position  Supination  external rotary movement of radius on ulna that results in hand moving from palm-down to palm- up position  Lateral epicondylitis (Tennis elbow)  Common problem usually involving extensor carpi radialis muscle (or other extensor muscles) near its origin on lateral epicondyle ▪ These muscles have a small area for attchment ▪ Great force applied to the lateral epicondyle when muscles contract  Associated with gripping & lifting activities  Medial epicondylitis (Golfer’s elbow) Associated with medial wrist flexor & pronator group near their origin on medial epicondyle somewhat less common Both conditions involve muscles which cross elbow but act primarily on wrist & hand  Origin:  Long head: supraglenoid tubercle  Short head: coracoid process  Insertion:  Radial tuberosity  Action:  Elbow flexion  Supination of forearm  Flexion of shoulder (weak) ▪ Long head  Origin:  Distal half of anterior humerus  Insertion:  Coranoid process of ulna  Action:  Elbow flexion  Origin:  Lateral distal 2/3 supracondylar ridge of humerus  Insertion:  Lateral surface of styloid process of radius  Action:  Elbow flexion  Pronation from supination to neutral  Supination from pronation to neutral  Origin:  Long head: infraglenoid tubercle of scapula  Lateral head: proximal ½ of posterior humerus  Medial head: Distal 2/3 of posterior humerus  Insertion:  Olecranon process of ulna  Action:  Extension of elbow (ALL 3 heads)  Long head: ▪ Extension, Horizontal abduction, and adduction of shoulder  Origin:  Posterior surface of lateral condyle of humerus  Insertion:  Posterolateral aspect of proximal ulna  Action:  Elbow extension  Origin:  Distal medial condyloid ridge of humerus & medial proximal ulna  Insertion:  Middle 1/3 of lateral radius  Action:  Pronation of forearm  Origin:  Distal ¼ of anterior side of ulna  Insertion:  Distal ¼ of anterior side of radius  Action:  Pronation of forearm  Origin:  Lateral epicondyle of humerus; neighboring posterior part of ulna  Insertion:  Lateral surface of proximal radius  Action:  Supination of forearm Supinator: KEY: Radius rotates on ulna Origin: Lateral epicondyle of humerus; neighboring posterior part of ulna Insertion: Lateral surface of proximal radius Picture: Moving from a pronated to a SUPINATED position Pronator KEY: Radius rotates on ulna Teres: Origin: Distal medial humerus and medial proximal ulna Insertion: Middle 1/3 of lateral radius Picture: Moving from a supinated to a Pronated position Pronator KEY: Radius rotates on ulna Quadratus: Origin: Distal ¼ of anterior side of ulna Insertion: Distal ¼ of anterior side of radius Picture: Moving from a supinated to a Pronated position  Ex. Lift portion of the biceps curl  Agonists  Biceps brachii  Brachialis  Brachioradialis 6-46  EX. Up portion of the push-up  Agonists  Triceps brachii ▪ Anconeus  Agonists  Pronator teres  Pronator quadratus  Brachioradialis 6-48  Agonists  Biceps brachii  Supinator muscle  Brachioradiali s 6-49  Elbow flexors – located anteriorly  Biceps brachii  Brachialis  Brachioradialis  Elbow extensor – located posteriorly  Triceps brachii  Anconeus provides assistance 6-50  Anterior  Primarily flexion & pronation ▪ Biceps brachii ▪ Brachialis ▪ Brachioradialis ▪ Pronator teres ▪ Pronator quadratus 6-51  Posterior  Primarily extension & supination ▪ Triceps brachii ▪ Anconeus ▪ Supinator 6-52