wsa5 - LAB 5: BONES AND MUSCLES OF THE FOREARM AND HAND...

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Unformatted text preview: LAB 5: BONES AND MUSCLES OF THE FOREARM AND HAND BONE AND BONY LANDMARK IDENTIFICATION Bony Landmarks of the Humerus (Distal) •olecranon fossa •lateral epicondyle •coronoid fossa •capitulum •radial groove •trochlea •medial epicondyle •radial fossa Bony Landmarks of the Radius •head of radius •neck of radius •shaft of radius •radial tuberosity •styloid process •articular surface for carpal bones Bony Landmarks of the Ulna •olecranon •trochlear notch •coronoid process •radial notch of ulna •ulnar tuberosity •shaft of ulna •articular surface for carpal bones •styloid process of ulna Bones of the Hand •scaphoid •lunate •triquetrum •pisiform •trapezium •trapezoid •capitate •hamate •metacarpals •distal phalanges •middle phalanges •proximal phalanges **note that the thumb has only proximal and distal phalanges** 1. Which carpals articulate (connect) with the distal radius? ______________ 2. Which metacarpals articulate with the hamate? ______________ Tania 09-9-4 1:43 PM Comment: Scaphoid, lunate Tania 09-9-4 1:43 PM 3. Compare the range of motion when you abduct your wrist vs. wrist adduction. Is one movement more limited than the other? What do you think accounts for this difference? Comment: Metacarpal 4 & 5 4. Find/palpate the following landmarks: Comment: Adduction (ulnar deviation) range greater than abduction (radial deviation) – because radial styloid process extends further out than the ulnar styloid process o medial and lateral epicondyles of humerus Tania Lam 09-9-4 1:43 PM o styloid processes of the radius and ulna, and the olecranon. o pisiform 5. What bony landmarks make up the knuckles? _________________________________ Tania 09-9-4 1:43 PM Comment: Heads of metacarpals ELBOW AND RADIOULNAR JOINTS Humeroulnar Joint: the trochlear notch of the ulna with the trochlea of the humerus. Use the models to verify these statements: When the elbow is in full extension, the olecranon process of the ulna articulates with the olecranon fossa of the humerus. When the elbow is flexed, the coronoid process of the ulna articulates with the coronoid fossa of the humerus. Humeroradial Joint: the head of the radius with the capitulum of the humerus. Use the models to verify this: When the elbow is in full extension, there is no contact between the capitulum and the radial head. Proximal Radioulnar Joint: radial head with radial notch of ulna. Distal Radioulnar Joint: ulnar notch of radius with distal end of ulna (head of ulna). Movement of the forearm consists of supination (palm down to palm up) and pronation (palm up to palm down). Use the models and palpate on yourself to verify this: In supination, the radius and ulna lie parallel to each other. In pronation, the radius crosses over the ulna at the proximal (superior) radioulnar joint. Wrist Joint: distal end of the radius with the scaphoid and lunate; distal end of the ulna with the lunate and triquetrum. Carpal Joints (Intercarpal Joints): synovial joints between the carpal bones. Movements at these joints are limited, but they do contribute to positioning the hand for abduction, adduction, flexion, and extension. Carpometacarpal Joints (CMC Joints): There are 5 of these joints between the distal row of the carpal bones and the metacarpal bones. Movement at the first carpometacarpal joint (the thumb) is quite flexible, allowing extension, flexion, adduction, abduction, rotation, and circumduction, while movements at CMC II ­V are more limited. Metacarpophalangeal Joints (MCP Joints): These are the joints between the distal head of the metacarpals and the proximal phalanges. Interphalangeal Joints (IP Joints): These are hinge joints that allow mainly flexion and extension. 6. Which bones make up the distal IP joints (DIP joints)? ___________________________ 7. Which bones make up the proximal IP joints (PIP joints)? ________________________ Tania 09-9-4 1:43 PM Comment: Between middle and distal phalanges Tania 09-9-4 1:43 PM Comment: Between middle and proximal phalanges MUSCLES THAT ACT AT THE ELBOW Posterior Compartment – Triceps Group Origin •Triceps Brachii Insertion Action Long head: infra ­glenoid tubercle of scapula Lateral head: upper ½ of posterior humerus Olecranon process of ulna Medial head: lower ½ of posterior humerus Extends elbow (long head of triceps also helps extend arm at shoulder joint) Anterior Compartment – Brachial Group Origin Insertion Action •Brachialis Flexes elbow Lower half of humerus (anterior) Coronoid process of ulna and ulnar tuberosity •Brachioradialis lateral edge of distal humerus •Biceps Brachii Long head: supra ­ glenoid tubercle of scapula styloid process of radius Elbow flexion, esp at neutral supination/pronation (“beer ­drinking muscle”) Radial tuberosity Flexes elbow, supinates forearm (weak flexion of arm at shoulder) Short head: coracoid process of scapula MUSCLES OF THE FOREARM FLEXORS Superficial Layer Intermediate Layer Deep Layer •flexor carpi radialis •flexor digitorum superficialis •flexor pollicis longus •flexor carpi ulnaris •flexor digitorum profundus •pronator teres •pronator quadratus •palmaris longus MUSCLES OF THE FOREARM – EXTENSORS Superficial Lateral Group Superficial Posterior Group Deep Layer •extensor carpi radialis longus •extensor digitorum •supinator •extensor carpi radialis brevis •abductor pollicis longus •extensor carpi ulnaris •extensor digiti minimi •extensor pollicis brevis •extensor pollicis longus •extensor indicis MUSCLES OF THE HAND Hypothenars Intermediate Layer Deep Layer •abductor digiti minimi •abductor pollicis brevis •dorsal interossei •flexor digiti minimi brevis •flexor pollicis brevis •palmar interossei •opponens digiti minimi •opponens pollicis •adductor pollicis Tania Lam 09-9-4 1:43 PM Comment: flex elbow with forearm pronated Tania Lam 09-9-4 1:43 PM Comment: Tania Lam 09-9-4 1:43 PM Comment: medial epicondyle of the humerus 8. How would you isolate contraction of the brachialis from biceps brachii? 9. a) The forearm flexor muscles are located on the anterior / posterior side of the forearm. b) Many of these muscles originate from the same bony landmark (the ‘common flexor origin’) – identify this landmark: _____________________________________________ 10. a) The forearm extensor muscles are located on the anterior / posterior side of the forearm. b) Many of these muscles originate from the same bony landmark (the ‘common extensor origin’) – identify this landmark: _____________________________________________ 11. Which of these muscles flex the wrist? 12. Which of these muscles extend the wrist? 13. a) Which of these muscles abduct the wrist? b) What is another way to describe wrist abduction? 14. a) Which of these muscles adduct the wrist? b) What is another way to describe wrist adduction? 15. Which of these muscles pronate the forearm? 16. Which of these muscles supinate the forearm? 17. a) Which muscles allow you to make a fist? b) Use anatomical terminology to describe this movement. c) How would you distinguish between the actions of the 2 finger flexor muscles? d) Which muscle is responsible for thumb flexion? 18. a) Which muscles allow you to open your hand? Tania Lam 09-9-4 1:43 PM Comment: Tania Lam 09-9-4 1:43 PM Comment: lateral epicondyle of the humerus Tania Lam 09-9-4 1:43 PM Comment: FCR, FCU, Palmaris longus, FDS Tania Lam 09-9-4 1:43 PM Comment: ECRL, ECRB, ECU, ED Tania Lam 09-9-4 1:43 PM Comment: FCR, ECRL, ECRB Tania Lam 09-9-4 1:43 PM Comment: Radial deviation Tania Lam 09-9-4 1:43 PM Comment: FCU, ECU Tania Lam 09-9-4 1:43 PM Comment: Ulnar deviation Tania Lam 09-9-4 1:43 PM Comment: pronator teres, pronator quadratus Tania Lam 09-9-4 1:43 PM Comment: supinator Tania Lam 09-9-4 1:43 PM Comment: FDS, FDP, flexor pollicis longus Tania Lam 09-9-4 1:43 PM Comment: flexion of the metacarpal ­phalangeal and distal and proximal inter ­phalangeal joints Tania Lam 09-9-4 1:43 PM Comment: flexor pollicis longus Tania Lam 09-9-4 1:43 PM Comment: extensor digitorum, extensor digiti minimi, extensor indicis, extensor pollicis brevis, extensor pollicis longus b) Use anatomical terminology to describe this movement. c) Differentiate between the actions of the 2 thumb extensor muscles. Which one is best suited to make a hitchhiker’s thumb? Tania Lam 09-9-4 1:43 PM Comment: extension of the metacarpal ­ phalangeal and distal and proximal inter ­phalangeal joints Tania Lam 09-9-4 1:43 PM 19. From which carpal bones do the hypothenar muscles originate? Comment: EPB extends thumb at MCP joint only; EPL can extend thumb at IP joint 20. To which bones do the hypothenar muscles attach? Thus, the hypothenar muscles are responsible for movements at which finger? Comment: EPL 21. From which carpal bones do most of the thenar muscles originate? Comment: pisiform, hamate 22. To which bones do the thenar muscles attach? Thus, the thenar muscles are responsible for movements at which finger? Comment: 5 proximal phalange and 5 metacarpal 23. Where do the interossei muscles originate and insert? Tania Lam 09-9-4 1:43 PM Tania Lam 09-9-4 1:43 PM Tania Lam 09-9-4 1:43 PM th th Tania Lam 09-9-4 1:43 PM th Comment: 5 finger Memory Tip: Tania Lam 09-9-4 1:43 PM The palmar interossei ADduct the fingers PAD. Comment: scaphoid, trapezium (adductor pollicis from cpaitate, trapezoid) The dorsal interossei ABduct the fingers DAB. ANATOMICAL SNUFFBOX The anatomical snuffbox describes a triangular depression formed on the posterior ­lateral side of the wrist that is most apparent when the thumb is extended. 24. With your thumb extended, palpate the floor of the anatomical snuffbox. Which carpal bones lie here? 25. Which tendons form the medial border of the anatomical snuffbox? 26. Which tendons form the lateral border? SURFACE ANATOMY Contract and palpate the following: o biceps brachii o triceps brachii o the thenar eminence o the hypothenar eminence o tendon of flexor carpi ulnaris o tendon of flexor carpi radialis o tendon of palmaris longus (Do you have it? How many people in the class do not have this muscle?) Tania Lam 09-9-4 1:43 PM st Comment: 1 proximal phalanx and metacarpal Tania Lam 09-9-4 1:43 PM Comment: thumb Tania Lam 09-9-4 1:43 PM Comment: from metacarpals Tania Lam 09-9-4 1:43 PM Comment: to corresponding phalanges Tania Lam 09-9-4 1:43 PM Comment: If you slightly flex your wrist, you should feel 3 tendons pop out (2 if you do not have palmaris longus). The most lateral tendon is that of flexor carpi radialis while the most medial one is flexor carpi ulnaris. If you have palmaris longus, you can really make it pop out if you slightly flex and th oppose your thumb to your 5 digit. Tania Lam 09-9-4 1:43 PM Comment: scaphoid and trapezium Tania Lam 09-9-4 1:43 PM Comment: extensor pollicis longus Tania Lam 09-9-4 1:43 PM Comment: abductor pollicis longus, extensor pollicis brevis Tania Lam 09-9-4 1:43 PM Comment: flex elbow (preferably against resistance) to expose muscle Tania Lam 09-9-4 1:43 PM Comment: extend elbow (preferably against [1] ... resistance) to expose muscle Tania Lam 09-9-4 1:43 PM Comment: bulk below the thumb Tania Lam 09-9-4 1:43 PM th Comment: fleshy bulk below the 5 finger Tania Lam 09-9-4 1:43 PM Comment: If you slightly flex your wrist, you [2] ... should feel 3 tendons pop out (2 if you do not have palmaris longus). The most lateral tendon is that of flexor carpi radialis while the most medial one is flexor carpi ulnaris. If you have palmaris longus, you can really make it pop out if you slightly flex and th oppose your thumb to your 5 digit. ...
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